Seedless plants | Biology for Seniors II (2023)

classify seedless plants

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Figure 1. Seedless plants, such as these horsetails (Equisetum sp..), thrive in moist, shady environments under tree canopies where drought is rare. (Credit: Modification of Jerry Kirkhart's work)

An incredible variety of seedless plants populate the Earth's landscape. Mosses can grow on a tree trunk, and horsetails can flaunt their jointed stems and slender leaves on the forest floor. Today, seedless plants represent only a small fraction of the plants in our environment; However, three hundred million years ago, seedless plants dominated the landscape, growing in the vast swampy forests of the Carboniferous. Its decomposition created large deposits of coal that we mine today.

Current evolutionary thought holds that all plants, both green and terrestrial algae, are monophyletic; that is, they are descendants of a single common ancestor. The evolutionary transition from water to land imposed severe limitations on plants. They had to develop strategies to prevent dehydration, airborne reproductive cells, structural support, and to capture and filter sunlight. While seed plants developed adaptations that allowed them to colonize even the driest habitats on Earth, not all plants were completely independent of water. Most seedless plants still require a moist environment.

learning goals

  • Describe the time line of plant evolution and the influence of land plants on other living things.
  • Describe the common properties of green algae and land plants.
  • Identify the main characteristics of mosses
  • Distinguish between vascular and non-vascular plants.
  • Identify the main characteristics of seedless vascular plants

beginning of plant life

Kingdom Plantae is a large and diverse group of organisms. More than 300,000 species of plants have been catalogued. Of these, more than 260,000 are seed plants. Mosses, ferns, conifers, and flowering plants are all members of the plant kingdom. Most biologists also consider green algae to be plants, while others exclude all algae from the plant kingdom. The reason for this disagreement stems from the fact that only green algae, thecarophyte, share common traits with land plants (such as the use of chlorophyllamibmore carotene in the same proportion as plants). These properties are absent from other types of algae.

Algae and the evolutionary pathways of photosynthesis

Some scientists consider all algae to be plants, while others claim that only charophytes belong to the kingdom Plantae. These divergent opinions are related to the different evolutionary pathways for photosynthesis chosen in different species of algae. Although all algae are photosynthetic, meaning they contain some type of chloroplast, not all algae become photosynthetic in the same way.

The ancestors of green algae became photosynthetic about 1.65 billion years ago through endosymbiosis of a photosynthetic green bacterium. This lineage of algae evolved into charophytes and eventually modern mosses, ferns, gymnosperms, and angiosperms. Its evolutionary trajectory was relatively linear and monophyletic. In contrast, the other algae (red, brown, gold, Stramenopiles, etc.) became photosynthetic through secondary or even tertiary endosymbiotic events; that is, they enter into endosymbiosis with cells that already have endosymbiosis with a cyanobacterium. These photosynthetic stragglers resemble charophytes in terms of autotrophy, but they have not spread to the same extent as charophytes, nor have they colonized land.

Different opinions about whether all algae are plants arise when considering these evolutionary pathways. Scientists who follow only straight lines of evolution (i.e., monophyly) consider only charophytes to be plants. To biologists who cast a wide net on creatures that share a common trait (in this case, photosynthetic eukaryotes), all algae are plants.

yours isinteractive websiteto get a deeper insight into charophytes.

Plant adaptations to life on land

As organisms adapted to life on land, they had to deal with various challenges in the terrestrial environment. Water is called the "stuff of life." The interior of the cell is a watery soup: it is in this medium that most small molecules dissolve and diffuse, and where most of the chemical reactions of metabolism take place. Dehydration, or dryness, is a constant threat to an organism exposed to air. Even if parts of a plant are close to a water source, aerial structures are likely to dry out. Water also gives organisms buoyancy. On land, plants need to develop structural support in an environment that does not offer the same support as water. The organism is also subject to bombardment by mutagenic radiation because the air does not filter the ultraviolet rays of sunlight. Also, the male gametes have to catch up with the female gametes with new strategies, since swimming is no longer possible. Therefore, both gametes and zygotes must be protected from desiccation. Successful land plants have developed strategies to meet all of these challenges. Not all settings appeared at once. Some species have never strayed far from the aquatic environment, while others have conquered the driest environments on land.

To balance these survival challenges, life on land offers several benefits. First, sunlight is abundant. The water acts as a filter, changing the spectral quality of the light absorbed by the photosynthetic pigment chlorophyll. Second, carbon dioxide is more readily available in air than in water because it diffuses more easily into the air. Third, land plants evolved before land animals; Therefore, no predators threatened plant life until the mainland was colonized by animals. This situation changed when the animals came out of the water and fed on the abundant sources of nutrients from the established flora. Plants, in turn, have evolved strategies to thwart predators: from thorns and prickles to toxic chemicals.

Like the first land animals, the first land plants lived near an abundant source of water and developed strategies to survive drought. Such a strategy is called leniency. For example, many mosses can dry out to a brown, brittle mat, but once rain or flood water makes the water available, the mosses will absorb it and restore their green, healthy appearance. Another strategy is to colonize high humidity environments where droughts are rare. Considered a lineage of early plants, ferns thrive in cool, moist places, like the undergrowth of temperate forests. Later, plants moved away from humid or aquatic environments using desiccation resistance instead of tolerance. These plants, like cacti, minimize water loss enough to survive in extremely dry environments.

The most successful adaptation solution was the development of new structures that gave plants an advantage in colonizing new, arid environments. Four main adaptations are found in all land plants: alternation of generations, a sporangium in which spores are formed, a gametangium that produces haploid cells, and apical meristem tissue in roots and shoots. The development of a waxy cuticle and a lignin-laden cell wall also contributed to the success of land plants. These adaptations are conspicuous by their absence in the closely related green algae, another reason for the debate over their classification in the plant kingdom.

generational relief

The alternation of generations describes a life cycle in which an organism exhibits haploid and diploid multicellular stages (Figure 2).

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Figure 2. The alternation of generations between the 1n gametophyte and the 2n sporophyte is shown. (Image credit: Peter Coxhead)

plotrefers to a life cycle in which there is a dominant haploid stage, anddiplomaticrefers to a life cycle in which diploid is the dominant life stage. The man is diplomatic. Most plants exhibit alternation of generations, described asHaplodiplodontia:The haploid multicellular form, the so-called gametophyte, is followed in the developmental sequence by a diploid multicellular organism, the sporophyte. The gametophyte produces gametes (reproductive cells) through mitosis. This may be the most obvious phase of the plant's life cycle, as in mosses, or it may appear in a microscopic structure, such as a pollen granule, in higher plants (a common collective term for vascular plants). The sporophyte stage is hardly recognizable in lower plants (collective term for mosses, liverworts, and lichens). Majestic trees are the diplomatic phase in the life cycle of plants like redwoods and pines.

Embryo protection is an important requirement for terrestrial plants. The vulnerable embryo must be protected from dehydration and other environmental hazards. In both seedless and seed-bearing plants, the female gametophyte provides protection and nutrients to the embryo as it develops into the new generation of sporophytes. This distinctive feature of land plants gave the group its alternate name.embryophytes.

sporangia in seedless plants

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Figure 3. In this photograph of the moss Sporangios bryum, spore-producing sacs called sporangia grow on the ends of long, slender stems. (Image credit: Javier Martin)

The sporophyte of seedless plants is diploid and results from the syngamy (fusion) of two gametes. The sporophyte bears the sporangia (singular, sporangium): organs that first appeared in land plants. The term "sporangium" literally means "spore in a container" as it is a reproductive sac that contains spores.sporocytes, or parent cells, produce haploid spores by meiosis, with the secondnorteChromosome number reduced to 1norte(Note that many plant sporophytes are polyploid: for example, durum wheat is tetraploid, bread wheat is hexaploid, and some ferns are 1000 ploid.) Subsequently, the spores are released from the sporangia and dispersed into the environment. Two different types of spores are produced in land plants, leading to segregation of the sexes at different points in the life cycle.Seedless plants without vesselsThey produce only one type of spores and are namedhomosporized🇧🇷 In these plants the gametophyte phase dominates. After germinating from a spore, the resulting gametophyte produces male and female gametangia, usually in the same individual. Unlike,heterosporadoPlants produce two morphologically distinct types of spores. The male spores are calledmicrosporic, due to its smaller size, and develop in the male gametophyte; the comparatively largestdustybecome the female gametophyte. Heterospory is seen in someSamenlose Gefäßpflanzenand in all seed plants.

When the haploid spore germinates in a hospitable environment, it produces a multicellular gametophyte through mitosis. The gametophyte supports the zygote formed by the fusion of gametes and the resulting young sporophyte (vegetative form). The cycle then starts all over again.

The spores of seedless plants are surrounded by thick cell walls that contain a tough polymer known assporopollenin🇧🇷 This complex substance is characterized by long chains of organic molecules related to fatty acids and carotenoids: hence the yellow color of most pollen. Sporopolenin is exceptionally resistant to chemical and biological degradation. In seed plants that use pollen to transfer male sperm to female ovule, sporopollenin resistance explains the existence of well-preserved pollen fossils. Sporopollenin was once considered an innovation of land plants; However, green algaeColeochaetesforms spores that contain sporopolenin.

Gametangium in seedless plants

gametangia(singular, gametangium) are structures found in multicellular haploid gametophytes. In the gametangium, gametes develop from progenitor cells by mitosis. The male gametangium (Antheridium) releases sperm. Many seedless plants produce sperm cells equipped with flagella that allow them to swim in a moist environment.archegon: the female gametangium. The embryo develops as a sporophyte within the archegonia. Gametangia are found in seedless plants, but are rarely found in seed plants.

meristemo apical

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Figure 4. The addition of new cells to a root occurs in the apical meristem. The subsequent increase in these cells causes the organ to grow and elongate. The cap protects the fragile apical meristem when the root tip is pushed through the soil by cell stretch.

Plant shoots and roots grow further through rapid cell division in a tissue called the apical meristem, which is a small patch of cells located at the top of the stem or root tip (Figure 4). The apical meristem consists of undifferentiated cells that continue to multiply throughout the life of the plant. Meristematic cells give rise to all the specialized tissues of the body. The elongation of shoots and roots gives the plant access to additional space and resources: light in the case of the shoots, and water and minerals in the case of the roots. A separate meristem called the lateral meristem produces cells that increase the diameter of tree trunks.

Additional adaptations of land plants.

As plants adapted to dry land and became independent of the constant presence of water in moist habitats, new organs and structures emerged. The first land plants grew no more than a few inches above the ground and competed for light on these low mats. By developing a bud and growing larger, the individual plants absorbed more light. Because air offers much less support than water, land plants built stiffer molecules in their stems (and later in the trunks of trees). For small plants like B. unicellular algae, a simple diffusion is enough to distribute water and nutrients throughout the organism. However, for plants to evolve into larger forms, the development of vascular tissue for the distribution of water and solutes was a prerequisite. The vasculature contains xylem and phloem tissues. The xylem carries water and minerals taken from the soil to the shoot, while the phloem carries the food obtained through photosynthesis throughout the plant. A root system developed to absorb water and minerals from the soil and to anchor the shoot higher and higher in the soil.

In land plants, a waxy, waterproof covering protects the cuticle, leaves, and stems from drying out. However, the cuticle also prevents the absorption of carbon dioxide, which is necessary for the synthesis of carbohydrates through photosynthesis. To overcome this, stomata, or pores, which open and close to regulate the movement of gases and water vapor, arose in plants as they moved from humid environments to drier habitats.

Water filters out ultraviolet B (UVB) light, which is harmful to all organisms, especially those that need to absorb light to survive. This filtering does not occur in land plants. This posed an additional challenge for the colonization of land, which was met by the development of biosynthetic pathways for the synthesis of protective flavonoids and other compounds: pigments that absorb ultraviolet wavelengths of light and protect the aerial parts of plants. of photodynamic damage.

Plants cannot avoid being eaten by animals. Instead, they synthesize a variety of toxic secondary metabolites: complex organic molecules such as alkaloids whose noxious odor and unpleasant taste deter animals. These toxic compounds can also cause serious illness and even death and deter predators. Humans have used many of these compounds as medicines, remedies, or spices for centuries. In contrast, when plants co-evolved with animals, the evolution of sweet and nutritive metabolites attracted animals to provide valuable assistance in the dispersal of pollen grains, fruits, or seeds. Plants have recruited animals to help them in this way for hundreds of millions of years.

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Evolution of land plants

No discussion of the evolution of land plants can be undertaken without a brief study of the time line of geological ages. The early era known as the Paleozoic is divided into six periods. It begins with the Cambrian, followed by the Ordovician, Silurian, Devonian, Carboniferous, and Permian. The main event that shaped the Ordovician, more than 500 million years ago, was the colonization of the land by the ancestors of modern land plants. Fossilized cells, cuticles, and spores of the earliest land plants have been dated to the Ordovician to early Paleozoic. The oldest known vascular plants have been identified in Devonian deposits. One of the richest sources of information is the Rhynie chert, a sedimentary rock deposit in Rhynie, Scotland (Figure 5) in which embedded fossils of some of the oldest vascular plants have been identified.

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Figure 5. This Rhynie chert contains fossilized vascular plant material. The area inside the circle contains underground bulbous stems called tubers and root-like structures called rhizoids. (B credit: Modified work by Peter Coxhead based on original image by "Smith609"/Wikimedia Commons; data to scale by Matt Russell)

Paleobotanists distinguish betweenextinctspecies, such as fossils, andexistingspecies that are still alive. The extinct vascular plants, classified as zosterophytes and trimerophytes, probably lacked leaves and true roots, and formed clumps of low vegetation similar in size to modern mosses, although some trimethophytes could reach a meter in height. the later genreCooksonia, which flourished during the Silurian, has been extensively studied using well-preserved examples. impressions ofCooksoniathey show slender branching stems ending in what appear to be sporangia. From the specimens recovered, it cannot be determined with certainty whetherCooksoniaThey had vascular tissue. Fossils indicate that at the end of the Devonian, ferns, horsetail, and seed plants populated the landscape and gave rise to trees and forests. This lush vegetation helped oxygenate the atmosphere, making it easier for air-breathing animals to colonize the mainland. Plants also established early symbiotic relationships with fungi, creating mycorrhizae: a relationship in which the fungal network of filaments increases the efficiency of the plant's root system and the plants provide the fungus with byproducts of photosynthesis.


How organisms acquire traits that allow them to colonize new environments, and how the current ecosystem is formed, are fundamental questions of evolution. Paleobotany (the study of extinct plants) addresses these questions by analyzing fossilized specimens recovered from field studies and reconstructing the morphology of long-lost organisms. Paleobotanists trace the evolution of plants by tracking changes in plant morphology: clarifying the connection between extant plants and identifying common ancestors that share the same traits. This field attempts to find transitional species that fill in the gaps on the path to the evolution of modern organisms. Fossils form when organisms become trapped in sediments or environments where their forms are preserved. Paleobotanists collect fossil specimens in the field and place them in the context of the geologic sediments and other fossilized organisms that surround them. The activity requires great care to preserve the integrity of the delicate fossils and the rock strata in which they are found.

One of the most exciting recent developments in paleobotany is the use of analytical chemistry and molecular biology to study fossils. The maintenance of molecular structures requires an oxygen-free environment, since the oxidation and degradation of the material due to the activity of microorganisms depend on its presence. An example of the use of analytical chemistry and molecular biology is the identification of oleanan, a compound that deters pests. Until now, oleanan seemed to be reserved exclusively for flowering plants; However, it has now been recovered from Permian sediments, long before present dates for the appearance of the first flowering plants. Paleobotanists can also study fossil DNA, which can generate a wealth of information by analyzing and comparing the DNA sequences of extinct plants with those of living and related organisms. Through this analysis, evolutionary relationships for plant lineages can be constructed.

Some paleobotanists are skeptical about the conclusions drawn from the analysis of molecular fossils. For example, chemical materials of interest degrade rapidly when exposed to air during their initial isolation, as well as during subsequent handling. There is always a high risk of contamination of the samples with foreign material, mainly microorganisms. However, as technology becomes more sophisticated, analysis of fossilized plant DNA will provide valuable information about plant development and adaptation to a constantly changing environment.

The main divisions of land plants.

Green algae and land plants are grouped together in a subphylum called Streptophytina and are therefore called streptophytes. In another subdivision, land plants are divided into two large groups based on the absence or presence of vascular tissue, as detailed in Figure 6. Plants that lack vascular tissue made up of specialized cells for transporting water and nutrients are callednon vascular plants🇧🇷 Hepaticas, mosses and tomentosum are seedless, non-vascular plants that probably appeared early in the evolution of land plants. Vascular plants have evolved a network of cells that conduct water and solutes. The first vascular plants appeared in the late Ordovician and probably resembled lycophytes, which include mosses (not to be confused with mosses) and pterophytes (ferns, horsetails, and ferns). Lycophytes and pterophytes are called seedless vascular plants because they do not produce seeds. Seed plants or spermatophytes form the largest group of all extant plants and thus characterize the landscape. Seed plants include the nudibranchs, particularly the conifers (gymnosperms) which produce 'naked seeds', and the most successful of all plants, the flowering plants (angiosperms). Angiosperms house their seeds in chambers in the center of a flower; the chamber walls then transform into a fruit.

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Figure 6. This table shows the main divisions of green plants.

practical matter

Which of the following statements about business divisions is incorrect?

  1. Lycophytes and pterophytes are vascular plants without seeds.
  2. All vascular plants produce seeds.
  3. All nonvascular embryophytes are bryophytes.
  4. Seed plants include angiosperms and gymnosperms.

Show response

Green algae: precursors of land plants


Until recently, all photosynthetic eukaryotes were considered members of the kingdom Plantae. However, the brown, red, and gold algae were assigned to the kingdom Protista. Because in addition to its ability to capture light energy and fix CO2, lack many structural and biochemical features that distinguish plants from protists. The position of green algae is ambiguous. Green algae contain the same carotenoids and chlorophyllamiblike land plants, while other algae have other accessory pigments and types of chlorophyll molecules in addition to chlorophylla🇧🇷 Both green algae and land plants also store carbohydrates in the form of starch. Green algae cells divide along cell plates called phragmoplasts, and their cell walls are layered similar to embryophyte cell walls. Consequently, the closely related land plants and green algae are now part of a new monophyletic group called the Streptophyta.

The remaining green algae, which belong to a group called the Chlorophyta, include more than 7,000 different species that live in freshwater, brackish water, seawater, or snow patches. Some green algae even survive in soil as long as it is covered by a thin film of moisture in which to live. Periodic dry periods provide a selective advantage for algae that can survive water stress. You should already be familiar with some particular green algae.spirogyreand desmidos. Their cells contain chloroplasts, which come in a dizzying variety of shapes, and their cell walls contain cellulose, just like land plants. Some green algae are unicellular, such asChlorellamichlamydomonas, which increases the ambiguity of the classification of green algae since the plants are multicellular. Other algae likeulva(commonly called sea lettuce) form colonies (Figure 7).

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Figure 7. Chlorophyta includes (a)spirogyre, (b) desmídias, (c)chlamydomonas, mi (d)Ulva.Desmids echlamydomonasthey are unicellular,spirogyreforms chains of cellsulvaforms leaf-like colonies (Credit b: work modified by Derek Keats; Credit c: work modified by Dartmouth Electron Microscope Facility, Dartmouth College; Credit d: work modified by Holger Krisp; Scale bar data by Matt Russell )

Reproduction of green algae.

Green algae reproduce both asexually, by fragmentation or dispersal of spores, and sexually, producing gametes that fuse during fertilization. In a unicellular organism likechlamydomonas, there is no mitosis after fertilization. in the multicellular organismulva, a sporophyte grows by mitosis after fertilization. Both of themchlamydomonasmiulvaproduce flagellated gametes.


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Figure 8. A representative alga,Chara,It is a noxious weed in Florida where it clogs waterways. (Source: South Florida Information Access, US Geological Survey)

Green algae of the order Charales and Coleochetes (microscopic green algae that coat their spores with sporopolenin) are thought to be the closest living relatives of embryophytes. Charales dates back 420 million years. They live in a variety of freshwater habitats and range in size from a few millimeters to a meter in length. The representative species isChar(Figure 8), often called musk grass or skunk grass due to its unpleasant odor. Large cells form the thallus: the main stem of the algae. The branches emanating from the nodes are made up of smaller cells. The male and female reproductive structures are found in the nodules, and the spermatozoa have flagella. Unlike land plants, charales do not undergo alternation of generations in their life cycle. Charales exhibit a number of traits that are significant to their adaptation to life on Earth. They produce the compounds lignin and sporopolenin and form plasmodesmata, which connect the cytoplasm of neighboring cells. The egg and then the zygote form in a protected chamber in the mother plant.

New information from a recent and extensive analysis of green algae DNA sequences indicates that zygnematales are more closely related to embryophytes than to charales. Zygnematoles belong to the genus of the familyspirogyre.As DNA analysis techniques improve and new comparative genomics information emerges, the phylogenetic connections between species will change. Apparently, plant biologists have not yet solved the mystery of the origin of land plants.


Bryophytes are the group of plants that are the closest extant relatives of the earliest land plants. The first mosses (liver plants) probably appeared in the Ordovician, about 450 million years ago. Due to a lack of lignin and other strong structures, mosses are unlikely to form fossils. Some spores protected by sporopolenin survived and are attributed to the first mosses. In the Silurian, on the other hand, vascular plants spread across the continents. This compelling fact is used as evidence that nonvascular plants must have preceded the Silurian period.

More than 25,000 species of mosses thrive in moist habitats, although some live in deserts. They form the main flora of inhospitable environments such as the tundra, where their small size and tolerance to drought offer distinct advantages. They generally lack lignin and lack true tracheids (xylem cells specialized for transporting water). Instead, water and nutrients circulate in specialized conducting cells. Although the term non-tracheophyte is more accurate, bryophytes are commonly known as non-vascular plants.

In a moss, all conspicuous vegetative organs, including the photosynthetic leaf-like structures, the thallus, the stem, and the rhizoid that anchors the plant to its substrate, belong to the haploid organism, or gametophyte. The sporophyte is barely perceptible. Gametes formed by bryophytes swim with a flagellum, like the gametes of some tracheophytes. The sporangium, the multicellular sexual reproductive structure, is present in mosses and absent in most algae. The bryophyte embryo also remains attached to the mother plant, which protects and nourishes it. This is a characteristic of terrestrial plants.

Bryophytes are divided into three phyla: liverworts or hepaticophytes, tomentosum or anthocerotophytes, and bryophytes or true bryophytes.


hepatic(Hepaticophyta) are considered the plants most closely related to the ancestor that migrated to earth. Liverworts have colonized all terrestrial habitats on Earth, diversifying into more than 7,000 extant species (Figure 9).

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Figure 9. This 1904 drawing shows the variety of forms of the Hepaticophyta.

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Figure 10. A liverwort,Lunularia cruciata, showing its flat and lobed stem. The organism in the photo is in the gametophyte stage.

Some gametophytes form lobed green structures, as seen in Figure 10. The shape resembles liver lobes and thus provides the origin of the name given to the tribe. Openings can be seen in the livers that allow the movement of gases. However, these are not stomata as they do not actively open or close. The plant absorbs water on its entire surface and has no cuticle to prevent dehydration.

Figure 11 shows the life cycle of a liverwort. The cycle begins with the release of haploid spores from the sporangium that has developed into the sporophyte. The spores, dispersed by wind or water, germinate on flattened stalks attached to the substrate by thin unicellular filaments. The male and female gametangia develop on separate individual plants. After release, the male gametes swim to the female gametangium (archegonium) with the help of their flagella and fertilization occurs. The zygote grows into a small sporophyte that is still attached to the original gametophyte. It will produce the next generation of spores through meiosis. Liver plants can also reproduce asexually by breaking branches or spreading leaf fragments called shoots. In this latter playback mode, theexasperated- small intact pieces of whole plants produced in a cup on the stem surface (see Figure 11) - are splashed out of the cup by raindrops. The shoots then land nearby and develop into gametophytes.

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Figure 11. The life cycle of a typical liverwort is shown. (Credit: Modification of work by Mariana Ruiz Villareal)


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Figure 12. Hornroot grows as a tall, slender sporophyte. (Credit: Modification of Jason Hollinger's work)

oanthocera(Anthocerotophyta) belong to the broad group of mosses. They have inhabited a variety of terrestrial habitats, although they are never far from a source of moisture. The short, bluish-green gametophyte is the dominant stage in the life cycle of a tomentosum. The narrow tubular sporophyte is the defining characteristic of the group. The sporophyte arises from the original gametophyte and continues to grow throughout the life of the plant (Figure 12).

Stomata occur on tomentosum and are abundant on the sporophyte. Photosynthetic thallus cells contain a single chloroplast. The meristematic cells at the base of the plant continue to divide and increase in height. Many tomentosum form symbiotic relationships with cyanobacteria, which sequester nitrogen from the environment.

The life cycle of tomentosum (Figure 13) follows the general pattern of alternation of generations. Gametophytes grow as flat stalks in the soil with embedded gametangia. The flagellated spermatozoa swim to the archegonia and fertilize the eggs. The zygote develops into a long, slender sporophyte that eventually splits open and releases spores. Thin cells called pseudoelaters surround the spores and help transport them further into the environment. Unlike the elaters found in horsetails, the pseudoelaters of the tomentosa are single-celled structures. The haploid spores germinate and give rise to the next generation of gametophytes.

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Figure 13. The alternation of generations in tomentosum is shown. (Credit: Modified work by "Smith609"/Wikimedia Commons based on original work by Mariana Ruiz Villareal)


More than 10,000 kinds ofElkthey were catalogued. Their habitats range from the tundra, where they are the primary vegetation, to the undergrowth of tropical forests. In the tundra, the flattened rhizoids of mosses allow them to adhere to a substrate without penetrating frozen ground. Mosses retard erosion, store soil moisture and nutrients, and provide shelter for small animals and food for larger herbivores such as musk oxen. Mosses are very sensitive to air pollution and are used to monitor air quality. They are also sensitive to copper salts, which is why these salts are a common ingredient in commercially available lawn moss removal compounds.

Mosses form tiny gametophytes, which are the dominant phase of the life cycle. The flat, green structures, similar to true leaves but lacking vascular tissue, are spirally connected to a central stem. Plants absorb water and nutrients directly through these leaf-like structures. Some mosses have small branches. Some primitive features of green algae, such as B. flagellated spermatozoa are still present in mosses that depend on water for reproduction. Other characteristics of mosses are clearly adaptations to the mainland. For example, stomata are present on sporophyte stems, and a primitive vasculature runs along the sporophyte stem. Furthermore, mosses are anchored in multiple cells in the subsoil, be it soil, rock, or tiles.rhizoid🇧🇷 These structures are precursors to roots. They originate from the base of the gametophyte but are not the main route for the absorption of water and minerals. The lack of a true root system explains why it's so easy to grow moss mats from a tree trunk. The moss life cycle follows the pattern of alternation of generations as shown in Figure 14.

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Figure 14. This figure shows the life cycle of mosses. (Credit: Modification of work by Mariana Ruiz Villareal)

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Figure 15. This photograph shows the long, thin stems, called bristles, attached to the moss capsules.Thamnobryum alopecurum🇧🇷 (Photo credit: Modified work by Hermann Schachner)

The best known structure is the haploid gametophyte, which germinates from a haploid spore and initially aprotonema– usually a tangle of unicellular filaments hugging the ground. Cells resembling an apical meristem actively divide, giving rise to a gametophore composed of a photosynthetic stalk and sheet-like structures. Rhizoids form at the base of the gametophore. The gametangia of both sexes develop on separate gametophores. The male organ (the antheridium) produces many sperm, while the archegonium (the female organ) forms a single ovum. During fertilization, sperm travel down the throat to the uterus and join with the egg in the archegonia. Protected by the archegonium, the zygote divides and grows into a sporophyte that still has its foot attached to the gametophyte.

the thin oneseta(plural, bristles), as seen in Figure 15, contain tubular cells that transfer nutrients from the base of the sporophyte (the foot) to the sporangium orhaircut.

A structure calledperistomioenhances spore reproduction after the capsule tip has fallen into the dispersal. The concentric tissue around the mouth of the capsule consists of close-fitting triangular units, a bit like "teeth"; These open and close depending on the humidity and regularly release spores.

practical matter

Which of the following statements about the life cycle of moss is incorrect?

  1. The mature gametophyte is haploid.
  2. The sporophyte produces haploid spores.
  3. Calyptra shoots form a mature gametophyte.
  4. The zygote lodges in the uterus.

Show response

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vascular plants ortracheophyte, are the dominant and most conspicuous group of terrestrial plants. More than 260,000 species of tracheophytes represent more than 90% of the terrestrial vegetation. Several evolutionary innovations explain its success and ability to spread to all habitats.

Bryophytes may have made a successful transition from an aquatic habitat to land, but they still depend on water to reproduce, absorbing moisture and nutrients through the gametophyte surface. The lack of roots to absorb water and minerals from the soil, as well as the lack of reinforced conducting cells, limits bryophytes to small sizes. Although they can survive in reasonably dry conditions, they cannot reproduce and expand their habitat without water. Vascular plants, on the other hand, can reach enormous heights and thus successfully compete for light. Photosynthetic organs develop into leaves, and tubular cells or vascular tissues transport water, minerals, and fixed carbon throughout the organism.

In seedless vascular plants, the dominant stage of the life cycle is the diploid sporophyte. The gametophyte is now a discrete but still independent organism. Throughout the evolution of plants there is an apparent reversal of roles in the dominant phase of the life cycle. Seedless vascular plants still rely on water during fertilization because sperm must swim through a layer of moisture to reach the egg. This reproductive stage explains why ferns and their relatives are more common in humid environments.

Vascular tissues: xylem and phloem

The first fossils showing the presence of vascular tissue date from the Silurian period, about 430 million years ago. The simplest arrangement of conductor cells shows a pattern of xylem in the center surrounded by phloem.XilemaIt is the tissue responsible for the storage and transport of water and nutrients over long distances, as well as for the transfer of water-soluble growth factors from the organs of synthesis to the target organs. The tissue is made up of conducting cells known as tracheids and a supporting filler tissue called parenchyma. The conducting cells of the xylem pick up the connection.ligninon its walls and are therefore called lignified. Lignin itself is a complex polymer that is impermeable to water and provides mechanical strength to vascular tissue. With their rigid cell walls, the xylem cells support the plant and allow it to reach impressive heights. Tall plants have a selective advantage, as they can reach unfiltered sunlight and further disperse their spores or seeds, expanding their range. By growing larger than other plants, tall trees shade shorter plants and limit competition for valuable water and nutrients in the soil.

Bastit is the second type of vascular tissue; it transports sugars, proteins, and other solutes throughout the plant. Phloem cells are divided into sieve elements (conductor cells) and cells that carry the sieve elements. Together, the xylem and phloem tissues form the vasculature of plants.

Seedless plants | Biology for Seniors II (16)

Figure 16. Diagrams of xylem and phloem tissues

(Video) Seedless Plants

Roots: support for the plant

The roots are not well preserved in the fossil record. However, it seems that the roots appeared later in evolution than the vascular tissues. The development of an extensive network of roots represented a great innovation in vascular plants. Fine rhizoids attached the bryophytes to the substrate, but these rather fragile filaments did not provide the plant with a strong anchorage; They also did not absorb significant amounts of water and nutrients. Rather, the roots, with their extensive system of vascular tissue, transfer water and minerals from the soil to the rest of the plant. The extensive root network, which penetrates deep into the soil to reach water sources, further stabilizes the trees and acts as a ballast or anchor. Most roots form a symbiotic relationship with fungi, forming mycorrhizae that benefit the plant by greatly increasing the surface area for absorbing water, minerals, and nutrients from the soil.

Leaves, sporophylls and strobila

A third innovation introduces seedless vascular plants. Along with the prominence of the sporophyte and the development of vascular tissue, the appearance of true leaves enhanced their photosynthetic efficiency. With their increased surface area, the leaves capture more sunlight and use more chloroplasts to capture and convert light energy into chemical energy, which is then used to convert atmospheric carbon dioxide into carbohydrates. Carbohydrates are exported to the rest of the plant by directing cells in the phloem tissue.

The existence of two types of morphology suggests that the leaves of different groups of plants evolved independently. The first type of leaf is theMicrofilo, or "little leaf", which can be dated to 350 million years at the end of the Silurian. A microphyll is small and has a simple vasculature. A single unbranchedsah- a bundle of vascular tissue made up of xylem and phloem - runs down the center of the leaf. Microphylls may come from flattened lateral branches or from sporangia that have lost their ability to reproduce. Microphylls are present in mosses and probably predate development.megaphileor "big leaves", which are larger leaves with a pattern of branching veins. Megaphiles probably appeared independently several times throughout evolution. Its complex networks of veins suggest that multiple branches may have joined to form a flattened organ, with the spaces between the branches filled with photosynthetic tissue.

In addition to photosynthesis, leaves play another role in plant life. Pine cones, mature fern leaves, and flowers are allsporophile– Leaves structurally modified to support sporangia.EstrobiliThey are cone-shaped structures that contain sporangia. They are prominent in conifers and are commonly known as pine cones.

Ferns and other seedless vascular plants

By the end of the Devonian period, plants had developed vascular tissues, well-defined leaves, and root systems. With these benefits, the plants increased in height and size. During the Carboniferous period, swamp forests of mosses and horsetail (some specimens reaching more than 30 m (100 ft) in height) covered most of the country. From these forests arose the extensive coal deposits that gave the Carboniferous its name. In seedless vascular plants, the sporophyte has become the dominant phase of the life cycle.

Seedless vascular plants still require water for fertilization and most prefer a moist environment. Modern seedless tracheophytes include mosses, horsetails, ferns, and ferns.

Filo Lycopodiophyta: Clubmoss

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Figure 17. At the Moss Club asLycopodium clavatum, the sporangia are arranged in groups called strobili. (Credit: Cory Zanker)

oElk, the tribeLycopodiophyta, are the first group of seedless vascular plants. They dominated the Carboniferous landscape, growing into tall trees and forming large swamp forests. Modern club mosses are small perennial plants composed of a stem (which can branch) and microphylls (Figure 17). The phylum Lycopodiophyta consists of about 1,200 species, including the prickly pear (isoetais), die moose (Lykopodien) and spiny mosses (Elfzehn), neither of which are true mosses or bryophytes.

Lycophytes follow the pattern of alternation of generations observed in bryophytes, except that the sporophyte is the main stage of the life cycle. Gametophytes do not depend on the sporophyte for nutrients. Some gametophytes develop underground and form mycorrhizal associations with fungi. In clubmoss, the sporophyte gives rise to sporophylls, which are organized into strobila, conical structures that give the class its name. Lycophytes can be homosporous or heterosporous.

Phylum Monilophyta: Class Equisetopsida (Cola de Caballo)

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Figure 18. Horsetails thrive in a swamp. (Credit: Myriam Feldman)

Horsetails, ferns, and tree ferns belong to the phylum Monilophyta, withhorse tailplaced in the class Equisetopsida. the only genderEquisetumIt is the survivor of a large group of plants known as the Arthrophyta, which gave rise to large trees and entire swampy forests in the Carboniferous. Plants are generally found in wet, swampy environments (Figure 18).

The horsetail stem is characterized by the presence of joints or nodes, hence the name Arthrophyta (Arthritis– = „Junta“; –salida= "plant"). Leaves and branches spiral out of evenly spaced joints. The needle-shaped leaves do not contribute much to photosynthesis, most of which takes place on the green stem (Figure 19).

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Figure 19. The slender leaves arising from the joints are conspicuous on the horsetail plant. Horsetails were once used as scrubbers, earning them the nickname cleaning brushes. (Credit: Myriam Feldman)

Silica accumulates in epidermal cells and contributes to the stiffness of horsetail plants. Underground stems, known as rhizomes, anchor plants to the soil. Modern horsetails are homosporous and produce bisexual gametophytes.

Phylo Monilophyta: Class Psilotopsids

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Figure 20. The butter fernpsiloto noIt has striking green stems with bud-like sporangia. (Image credit: Forest and Kim Starr)

While most ferns form large leaves and branching roots, they are fernsbeat ferns, class Psilotopsida, without roots or leaves, probably lost by reduction. Photosynthesis takes place on their green stems, and small yellow bumps containing the sporangia form at the tip of the branch stem. Ferns were considered one of the first pterophytes. However, recent comparative DNA analysis suggests that this clade may have lost vascular tissue and roots during evolution and is more closely related to ferns.

Filo Monilophyta: Klasse Psilotopsida (Samambaias)

with its big leavesdo somethingthey are the most easily recognizable seedless vascular plants. They are considered the most advanced seedless vascular plants and have characteristics commonly seen in seed plants. More than 20,000 species of ferns live in environments ranging from the tropics to temperate forests.

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Figure 21. Some specimens of this small species of tree fern can grow very large. (Credit: Adrian Pingstone)

Although some species survive in dry environments, most ferns are restricted to moist, shady locations. Ferns appeared in the fossil record during the Devonian period and spread during the Carboniferous.

The predominant stage in a fern's life cycle is the sporophyte, consisting of large compound leaves called fronds. The fronds do double duty; They are photosynthetic organs that also carry reproductive organs. The stem may be buried underground as a rhizome, from which adventitious roots grow to absorb water and nutrients from the soil; or they can grow above the ground like a stem in ferns (Figure 21).CoincidentallyOrgans are those that grow in unusual places, like roots growing from side to side of a trunk.

The tip of a developing fern leaf wraps around a cane or fiddle head (Figure 22). Fiddleheads unfurl as the foliage develops.

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Figure 22. The croziers or violin heads are the tips of fern leaves. (Credit a: Factory mod by Cory Zanker; Credit b: Factory mod by Myriam Feldman)

The life cycle of a fern is shown in Figure 23.

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Figure 23. This fern life cycle shows alternation of generations with a dominant sporophyte stage. (Fern Credit: Modified work by Cory Zanker; Gametophyte Credit: Modified work by "Vlmastra"/Wikimedia Commons)

(Video) Seedless, Vascular Plants

practical matter

Which of the following statements about the life cycle of ferns is incorrect?

  1. The sporangia produce haploid spores.
  2. The sporophyte grows from a gametophyte.
  3. The sporophyte is diploid and the gametophyte is haploid.
  4. The sporangia are formed in the lower part of the gametophyte.

Show response

To see an animation of the life cycle of a fern and test your knowledge, go towebsite.

Seedless plants | Biology for Seniors II (24)

Figure 24. Sori appear as small bumps on the underside of a fern leaf. (Credit: Myriam Feldman)

Most ferns produce the same type of spores and are therefore homosporous. The diploid sporophyte is the most obvious stage of the life cycle. On the underside of its mature leaves, the sori (singular, sorus) form small clusters in which the sporangia develop (Figure 24).

Within the sera, the spores are produced by meiosis and released into the air. Those that land on a suitable substrate germinate and form a heart-shaped gametophyte attached to the soil by thin filamentous rhizoids (Figure 25).

The discrete gametophyte harbors both sexual gametangia. Flagellated sperm released from the antheridium swim across a moist surface to the archegonia, where the ovum is fertilized. The newly formed zygote becomes a sporophyte, which arises from the gametophyte and grows through mitosis into the next generation sporophyte.

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Figure 25. Here you can see a young sporophyte (pictured above) and a heart-shaped gametophyte (pictured below). (Credit: "Vlmastra" factory mod/Wikimedia Commons)


Looking at the flower beds and well-defined fountains on the grounds of Europe's royal palaces and historic residences, it's clear that the creators of the gardens knew more than just art and design. They were also familiar with the biology of the plants they selected. Landscaping also has strong roots in American tradition. An excellent example of early American classic design is Monticello: the private estate of Thomas Jefferson. Among his many interests, Jefferson retained a strong passion for botany. Landscape design can include a small private space such as a back garden; public gathering places like Central Park in New York City; or a plan of the entire city, such as Pierre L'Enfant's design for Washington, DC.

A landscape architect designs traditional public spaces, such as botanical gardens, parks, college campuses, gardens, and larger communities, as well as natural areas and private gardens. The restoration of natural areas affected by human intervention, such as wetlands, also requires the expertise of a landscaper.

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Figure 26. This landscape border on a college campus was designed by students in the college's Department of Horticulture and Landscaping. (Credit: Myriam Feldman)

With such a variety of skills required, a landscape architect's education includes a strong background in botany, soil science, plant pathology, entomology, and horticulture. Architecture courses and design software are also required to complete the course. Successful landscaping relies on a thorough understanding of plant growth requirements, such as light and shade, humidity levels, compatibility of different species, and susceptibility to pathogens and pests. Mosses and ferns thrive in a shady area where springs provide moisture; Cacti, on the other hand, would not do well in this environment. Future growth of individual plants must be considered to avoid displacement and competition for light and nutrients. The appearance of the room over time is also important. Shapes, colors and biology must be balanced for a well-maintained and sustainable green space. Art, architecture, and biology merge into a beautifully designed and executed landscape.

The importance of seedless vascular plants

Mosses and liverworts are often the first macroscopic organisms to colonize an area, both in primary succession, where bare soil is colonized first by living organisms, and in secondary succession, where the soil remains intact after a disaster, decimating many species. existing. Its spores are carried by the wind, birds or insects. Once established, mosses and liverworts provide food and shelter for other species. In a harsh environment like the tundra, where the ground is frozen, bryophytes grow well because they have no roots and can dry out quickly and rehydrate when water becomes available again. Mosses are the base of the food chain in the tundra biome. Many species, from small insects to musk oxen and reindeer, depend on mosses for food. Predators, in turn, feed on herbivores, which are the main consumers. Some reports suggest that mosses make the soil more conducive to colonization by other plants. By establishing symbiotic relationships with nitrogen-fixing cyanobacteria, mosses replenish the soil with nitrogen.

In the late 19th century, scientists noticed that lichens and mosses were becoming rarer in urban and suburban areas. Because mosses do not have a root system to absorb water and nutrients, nor a cuticle layer to protect them from drying out, contaminants from rainwater easily penetrate their tissues. They absorb moisture and nutrients through all their exposed surfaces. Therefore, dissolved pollutants in rainwater easily penetrate plant tissues and affect mosses more than other plants. The disappearance of mosses can be seen as a bioindicator of the level of environmental contamination.

Ferns contribute to the environment by promoting rock erosion, accelerating topsoil formation, and slowing erosion by spreading rhizomes into the soil. The aquatic ferns of the genusazollathey harbor nitrogen-fixing cyanobacteria and return this important nutrient to aquatic habitats.

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Figure 27.Sphagnum acutifoliumIt is dry peat and can be used as fuel. (Image credit: Ken Goulding)

Historically, seedless plants have played an important role in human life, being used as tools, fuel, and medicine. Driedtorfmoos,Esfagno, is widely used as a fuel in some parts of Europe and is considered a renewable resource.EsfagnoThe bogs (Figure 27) are cultivated with bramble and blueberry bushes. The ability toEsfagnoto retain moisture, moss is a common soil conditioner. Florists use blocks ofEsfagnoto maintain humidity in floral arrangements.

The attractive fronds of ferns make them a popular ornamental plant. Because they thrive in low light, they are suitable as houseplants. More importantly, fiddleheads are a traditional Native American spring food in the Pacific Northwest and are popular as a garnish in French cuisine. liquorice fern,Polypodium glicirriza,It is part of the diet of the coastal tribes of the Pacific Northwest, partly due to the sweetness of its rhizomes. It has a slight licorice flavor and serves as a sweetener. The rhizome is also listed in the Native American Pharmacopoeia for its medicinal properties and is used as a sore throat remedy.

yours iswebsiteto learn how to identify fern species by their fiddle heads.

However, by far the greatest impact on human life comes from their extinct ancestors. The tall mosses, horsetails, and tree ferns that flourished in Carboniferous swamp forests gave rise to vast coal deposits around the world. Coal was an abundant source of energy during the Industrial Revolution, which had tremendous consequences for human society, including rapid technological advances and the growth of large cities, as well as environmental degradation. Coal remains a primary source of energy and also a major contributor to global warming.

In short: seedless plants

Land plants acquired characteristics that allowed them to colonize land and survive out of water. All terrestrial plants share the following characteristics: alternation of generations, the haploid plant being called a gametophyte and the diploid plant a sporophyte; Embryo protection, haploid spore formation in a sporangium, gamete formation in a gametangium, and an apical meristem. Vascular tissue, roots, leaves, cuticles, and a tough outer layer that protects spores helped plants adapt to dry land. Land plants appeared about 500 million years ago in the Ordovician.

Based on DNA and structural analysis, green algae share more properties with land plants than other algae. Charales produce sporopolenin and lignin precursors, fragmentplasts, and have flagellated spermatozoa. They do not show alternation of generations.

Seedless avascular plants are small and the gametophyte is the dominant stage of the life cycle. Without a vascular system or roots, they absorb water and nutrients on all their exposed surfaces. The three main groups, known collectively as bryophytes, include liverworts, tomentoses, and mosses. Liverworts are the most primitive plants and are closely related to the earliest land plants. Poisonous mushrooms have developed stomata and have a single chloroplast per cell. Mosses have simple conductive cells and are connected to the substrate by rhizoids. They colonize hostile habitats and can regain moisture after drying out. The moss sporangium is a complex structure that allows the release of spores far from the parent plant.

Vascular systems are made up of xylem tissue, which transports water and minerals, and phloem tissue, which transports sugars and proteins. As the vascular system evolved, leaves arose, which functioned as large photosynthetic organs, and roots arose to access soil water. The small, uncomplicated leaves are microphyllous. Leaves with large veins are megaphyllous. Modified leaves that have sporangia are sporophylls. Some sporophylls are arranged in conical structures called strobila.

Seedless vascular plants include mosses, which are the most primitive; ferns that have lost leaves and roots through reductive evolution; and horsetails and ferns. Ferns are the most advanced group of seedless vascular plants. They are characterized by large leaves called fronds and small sporangia-containing structures called sori found on the underside of the fronds.

Mosses play an essential role in the balance of ecosystems; They are pioneer species that colonize bare or devastated environments and allow succession. They contribute to the enrichment of the soil and provide shelter and nutrients for animals in hostile environments. Mosses and ferns can be used for fuel and have culinary, medicinal and ornamental uses.

(Video) Seedless, Non-vascular Plants

check your understanding

Please answer the following questions to determine your understanding of the topics discussed in the previous section. this little quizNocounts towards your class grade and can be replayed an unlimited number of times.

Use this quiz to check your understanding and decide if you want to (1) continue studying the previous section or (2) move on to the next section.


What is the most common seedless plant? ›

Ferns. Ferns are the most common seedless vascular plants (Figure below). They usually have large divided leaves called fronds. In most ferns, fronds develop from a curled-up formation called a fiddlehead (Figure below).

What are some seedless plants? ›

Modern-day seedless vascular plants include club mosses, horsetails, ferns, and whisk ferns.

What are the disadvantages of seedless plants? ›

Remember that sexual reproduction of seedless plants lacks genetic diversity, produces less variation in offspring, and causes the organism to become less adaptable to particular environmental changes. As a result, entire communities will be unable to adapt to the harsh climate.

What are 2 seedless vascular plants? ›

The seedless vascular plants include club mosses, which are the most primitive; whisk ferns, which lost leaves and roots by reductive evolution; and horsetails and ferns.

What are 5 seedless fruits? ›

Name of seedless fruit:
  • Orange.
  • Fig.
  • Bananas.
  • Pineapple.
  • Grapes.

What does a seedless plant look like? ›

Such seedless plants include ferns, mosses, horsetails and liverworts. These plants have stems, roots, and leaves like other plants, but since they do not produce flowers, they have no seeds.

What is the most diverse seedless plant? ›

Ferns are considered the most advanced seedless vascular plants and display characteristics commonly observed in seed plants. Ferns form large leaves and branching roots.

What is the largest group of seedless plants? ›

The largest group of living seedless vascular plants—and probably the most familiar—are the ferns with about 12,000 species, over two‐thirds of which are tropical. Ferns are an ancient group.

Are seedless good for you? ›

Benefits of Seedless Grapes

If you've been to the supermarket recently, chances are you've only noticed seedless grapes. Because they're easier and more enjoyable to eat, many consumers prefer them over seeded options. Seedless grapes are also highly nutritious, containing phytonutrients, antioxidants, and vitamins.

Do seedless plants need water? ›

Seedless vascular plants reproduce through unicellular, haploid spores instead of seeds; the lightweight spores allow for easy dispersion in the wind. Seedless vascular plants require water for sperm motility during reproduction and, thus, are often found in moist environments.

What is another name for seedless plant? ›

Ferns, horsetails, and all the bryophytes are seedless plants. See more at bryophyte.

What are plants without seeds called? ›

Some plants don't produce flowers and seeds. Plants such as ferns and mosses are called nonflowering plants and produce spores instead of seeds. There is also another group called the Fungi, that include mushrooms, and these also reproduce by spores.

Which plant is considered the most advanced seedless vascular plant and why? ›

Ferns are the most advanced seedless vascular plants. Ferns have large leaves and branching roots. Ferns have developed stomata that allow them to conserve water.

What are 5 examples of vascular plants? ›

Vascular plants include the clubmosses, horsetails, ferns, gymnosperms (including conifers), and angiosperms (flowering plants). Scientific names for the group include Tracheophyta, Tracheobionta and Equisetopsida sensu lato.

Where can seedless plants be found? ›

With their large fronds, ferns are the most readily recognizable seedless vascular plants (Figure 14.2. 8). About 12,000 species of ferns live in environments ranging from tropics to temperate forests. Although some species survive in dry environments, most ferns are restricted to moist and shaded places.

What is an advantage of being a seedless plant? ›

Seedless plants have historically played a role in human life through uses as tools, fuel, and medicine. Dried peat moss, Sphagnum, is commonly used as fuel in some parts of Europe and is considered a renewable resource.

Where do seedless plants grow? ›

Most seedless plants live in damp and shady habitats. Certain types of mosses, called PEAT MOSSES, grow in vast expanses of wetlands in the northern parts of the world. Bryophytes do not have true roots. They have hairy, rootlike growths called rhizoids that anchor the plants to the soil, but do not draw up water.

What are the two types of seedless plant How are they different? ›

The two groups of seedless plants are nonvascular plants and seedless vascular plants. Mosses, liverworts, and hornworts do not have vascular tissue to transport water and nutrients. Each cell of the plant must get water from the environment or from a nearby cell.

Which plant produces seedless fruit? ›

DefH9-iaaM gene is expressed in the ovules and placenta but also in the tissues derived from them, allowing the synthesis of auxin also in later stages of fruit growth. This continuous supply of auxin produces seedless fruits that are equal or bigger in size compared to pollinated fruits.

Do seedless plants make their own food? ›

Plants (kingdom Plantae) are autotrophs; they make their own organic nutrients. The term “organic” refers to compounds that contain carbon. Organic nutrients such as sugars are made by photosynthesis.

Is banana a seedless plant? ›

As we know Banana is a seedless fruit. Banana is produced through pathogenesis.

What is the life cycle of seedless plants? ›

In vascular plants, the sporophyte generation is dominant. In seedless vascular plants such as ferns, the sporophyte releases spores from the undersides of leaves. The spores develop into tiny, separate gametophytes, from which the next generation of sporophyte plants grows.

What are the two disadvantages of seedless plants during reproduction? ›

ii Propagation of seedless plants is made possible. Two disadvantages: i No genetic variations so less adaptability to the environment. ii The disease of plants gets transferred to the offsprings.

Are grapes good for seniors? ›

Eating grapes may slow or help prevent the onset of age-related macular degeneration (AMD), a debilitating condition affecting millions of elderly people worldwide, say researchers. The antioxidant actions of grapes are believed to be responsible for these protective effects.

What is the disadvantage of seedless fruit? ›

Disadvantages. A disadvantage of most seedless crops is a significant reduction in the genetic diversity of the species. Because the plants are genetically identical clones, a pest or disease that affects one individual is likely capable of affecting each of its clones.

Are cucumbers good for you? ›

It's high in beneficial nutrients, as well as certain plant compounds and antioxidants that may help treat and even prevent some conditions. Also, cucumbers are low in calories and contain a good amount of water and soluble fiber, making them ideal for promoting hydration and aiding in weight loss.

Which four plants can be grown without seeds? ›

Potatoes, roses, and jasmine plants can grow without seeds. Q.

Do seedless plants produce oxygen? ›

Like all plants, seedless plants are producers, providing food for primary consumers and omnivores. Through photosynthesis, they reduce carbon dioxide in the atmosphere, and release oxygen into the atmosphere.

Are seedless plants natural? ›

Seedless plants are not common, but they do exist naturally or can be manipulated by plant breeders without using genetic engineering techniques. No current seedless plants are genetically modified organisms (GMOs).

What are the 2 seeds plants? ›

The two major types of seed plants are the gymnosperms (seeds in cones) and angiosperms(seeds in ovaries of flowers). Figure below shows how the seeds of gymnosperms and angiosperms differ. Do you see the main difference between the two seeds?

Is there any plant grow without seed? ›

Not every plant grows from a seed. Some plants, like ferns and mosses, grow from spores. Other plants use asexual vegetative reproduction and grow new plants from rhizomes or tubers.

What plant has no seeds but flowers? ›

Non-flowering plants include mosses, liverworts, hornworts, lycophytes and ferns and reproduce by spores. Some non-flowering plants, called gymnosperms or conifers, still produce seeds.

Which plant is the most advanced plant? ›

So, the correct answer is 'Angiosperm'

Do seedless vascular plants produce fruit? ›

Seedless vascular plants reproduce via spores but, unlike non-vascular plants (hornworts, mosses, and liverworts) have a vascular system with xylem and phloem, which transport water and nutrients (Figure 7.1. 1). They do not produce flowers, fruits, or seeds.

How many seedless vascular plants are there? ›

There are four types of seedless vascular plants: club mosses, whisk ferns, true ferns, and horsetails. The life cycle of a seedless vascular plant begins when haploid spores are produced by the sori and released into the atmosphere. They germinate into a gametophyte called the prothallus.

Is Avocado a vascular plant? ›

The vascular bundles serve an important purpose: They are the internal "plumbing" within the tree and connect the fruit to the rest of the tree (yes, avocados are a fruit). Arpaia explained that there are a few different reasons why some avocados develop more prominent vascular bundles, the first being simple genetics.

What are the simplest vascular plants? ›

The Pteridophytes are the most primitive vascular plants, having a simple reproductive system lacking flowers and seed. Pteridophytes evolved a system of xylem and phloem to transport fluids and thus achieved greater heights than was possible for their avascular ancestors.

Is tomato a vascular plant? ›

The tomato plant contains 2 types of vascular bundle. The large bundles of the stem form a network by joining above each node in combinations of 2 at a time.

What is the most common type of seedless nonvascular plant? ›

Seedless nonvascular plants are small, having the gametophyte as the dominant stage of the lifecycle. Without a vascular system and roots, they absorb water and nutrients on all their exposed surfaces. Collectively known as bryophytes, the three main groups include the liverworts, the hornworts, and the mosses.

What are the four major groups of seedless plants? ›

There are four types of seedless vascular plants: club mosses, whisk ferns, true ferns, and horsetails. The life cycle of a seedless vascular plant begins when haploid spores are produced by the sori and released into the atmosphere. They germinate into a gametophyte called the prothallus.

What do seedless plants grow from? ›

In seedless vascular plants, such as ferns and horsetails, the plants reproduce using haploid, unicellular spores instead of seeds. The spores are very lightweight (unlike many seeds), which allows for their easy dispersion in the wind and for the plants to spread to new habitats.

What are the 3 types of seedless vascular plants and which is the most common? ›

The seedless vascular plants include club mosses, which are the most primitive; whisk ferns, which lost leaves and roots by reductive evolution; horsetails, and ferns.


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