Every plant has three main parts: roots, stem and leaves. They are interconnected and ensure the normal growth and development of the body. But this applies only to evolutionarily more progressive plants. Such lower organisms as mosses, lichens and algae cannot boast of a high level of development, which means that their body is much simpler. For example, the functions of their roots are performed by rhizoids. What are rhizoids in algae, mosses and other primitively developed organisms? What is their evolutionary significance?

What are rhizoids? Definition

Rhizoids are thread-like parts that represent one or more cells and perform the functions of a root. Often they are colorless, short (their length can be limited to a few millimeters) and not very strong.

What are the differences between roots and rhizoids?

1. Rhizoids do not contain conductive tissues. Osmosis and the flow of water into the body is one of the main functions of the roots of the plant. If underground structures lack xylem and phloem, they cannot be considered true roots.
2. There is a big difference in the dimensions of the roots and rhizoids. If the former can reach tens of meters in length and a meter in width, then rhizoids are small, sometimes even microscopic formations.
3. The root is a collection of a huge number of cells and tissues. Rhizoids, in turn, can be formed by several or even one cell, depending on the functions.

However, one similarity can be seen immediately: both the root and the rhizoids perform the function of anchoring - holding the plant body in the soil. But even here one can make a reservation that the root copes with this function much more efficiently than rhizoids.

And yet rhizoids are a kind of precursor of true roots. These formations in the process of evolution gave rise to a new type, therefore they are of great importance in terms of the development of the fauna, and also attract the interest of botanists. That's what rhizoids are in biology.

Functions of rhizoids

The significance of these structures in biology is not limited to a large role in the evolutionary process. Rhizoids also perform some functions related to supporting the growth and development of mosses, lichens, and algae. Among them:

1. Retention of the main part of the plant in the soil or at the bottom of the reservoir, if we are talking about algae.
2. Gas exchange and soil loosening.
3. Avoiding excess water, too large drops of moisture.
4. Water absorption.

These are the most common functions that rhizoids of algae and mosses can perform.

Types of rhizoids

Not all subterranean moss and algae structures are alike. Even among such simple formations, specialization is observed depending on the functions and structure. What are rhizoids and what are they in nature?

Rhizoids can be smooth (simple) and reed. The first are the usual underground structures that serve to attach, stabilize the plant and keep it immobile.

Reed rhizoids differ in that their diameter is slightly smaller, the walls are thinner and wavy. Inside, such formations have outgrowths resembling papillae or tongues, from where their name came from. The function of such rhizoids is the supply of water by the capillary method, which is facilitated by such an unusual shape.

Also, when studying the "felt" of rhizoids, one can find intermediate variants of these structures, which have absorbed the features of both smooth and reed analogues. That's what rhizoids are in terms of the variety of structures.

What organisms have rhizoids?

Previously, mosses and algae belonged to lower plants, since their structure was evolutionarily less developed than that of spore and seed plants. In all representatives of the lichen kingdom, rhizoids are also observed, since this organism is a symbiotic relationship between algae and fungi. By the way, some representatives of fungi also form rhizoids.

Not all mosses possess these underground structures. For example, sphagnum, which lives in wetlands, absorbs water with the entire surface of the body, respectively, in this case, the formation of rhizoids is not necessary. The situation is the same for all sphagnum mosses.

What is the difference between rhizoids and rhizoids?

We learned what rhizoids are and what role they played in the evolutionary process for the entire biological world. However, there are intermediate underground structures that stand between the rhizoids and the rhizome on the evolutionary ladder. We are talking about rhizomoids - another type of root structures of more developed organisms than mosses or algae.

Rhizomoids are the precursor of the rhizomes of ferns and club mosses. They are formed by the interweaving of several rhizoids at once so closely, as if it were one continuous structure. However, they are not true roots for the same reason as the rhizoids of mosses, algae and lichens. Now it is clear what rhizoids are and how they differ from rhizoids.

what are rhizoids what functions do they perform and got the best answer

Answer from
Rhizoids (from the Greek rhíza - root and éidos - view), filamentous formations of one or more cells arranged in a row, in mosses, lichens, some algae and fungi (for example, in Rhizopus), which serve to attach to the substrate and absorb from it water and nutrients. In appearance, R. resemble root hairs. Marchantia mosses have special so-called reed mosses, which consist of dead cells through which water moves like a wick.

Rhizoid - an organ that replaces the root in those lower organized plants (Ploevtsy) that do not have true roots. Morphologically, it most closely resembles root hairs, from which in the simplest cases (in hepatic mosses, fern growths) it differs almost only in the presence of a septum at the base, and, therefore, it is a strongly elongated cell that serves to absorb nutrients from the soil. More perfectly educated, deciduous moss rhizomes represent a complex system of ramifications, and the diameter of the branches is constantly decreasing, so that in general such a rhizome quite resembles a real root, only in a small form. R. differ from root hairs in that they are sensitive to light and gravity, which makes them closer to real roots.

Answer from Elena Novichenko[guru]
Rhizoids are thin threads with which mosses, lichens, algae and fungi attach to the surface and receive moisture and nutrients. At their core, rhizoids are prototypes of the roots that plants have. As a matter of fact, the word rhizoids itself means “root-shaped” in translation. In the process of the development of life on Earth, first mosses, algae, fungi and lichens appeared, which had rhizoids instead of roots, and then higher plants, in which rhizoids developed into full-fledged roots.
The function of rhizoids, like roots, is to attach to the surface and obtain nutrients and water from it.

Answer from ***Tatyana***[newbie]
Rhizoids are filamentous formations of one or more cells arranged in a row, in mosses, lichens, some algae and fungi, which serve to attach to the substrate and absorb water and nutrients from it.

Answer from Yokubik[newbie]
Rhizoids (from Greek rhiza - root and eidos - view), filamentous formations of one or more cells arranged in a row, in mosses, lichens, some algae and fungi (for example, in Rhizopus), which serve to attach to the substrate and absorb from it water and nutrients. In appearance, R. resemble root hairs. Marchantia mosses have special so-called reed mosses, which consist of dead cells through which water moves like a wick.
These are filamentous formations in mosses, fern-like growths, lichens, some algae and fungi that act as a root.
Rhizoid - an organ that replaces the root in those lower organized plants (Ploevtsy) that do not have true roots. Morphologically, it most closely resembles root hairs, from which in the simplest cases (in hepatic mosses, fern growths) it differs almost only in the presence of a septum at the base, and, therefore, it is a strongly elongated cell that serves to absorb nutrients from the soil. More perfectly educated, deciduous moss rhizomes represent a complex system of ramifications, and the diameter of the branches is constantly decreasing, so that in general such a rhizome quite resembles a real root, only in a small form. R. differ from root hairs in that they are sensitive to light and gravity, which makes them closer to real roots.

1. What parts does the moss body consist of? Compare the structure of mosses and multicellular algae.
Moss consists of leaves and stems, then its main organs and tissues.
Mosses and multicellular algae have rhizoids, this is their main similarity.

2. How do mosses attach themselves to the soil if they don't have roots?

To the soil and other places where moss lives, it is attached with the help of rhizoids, which resemble thin threads.

3. What is an important condition for the existence of mosses?

The main thing is that there is moisture and water, without water the moss will not be able to multiply.

4. What is the structure of the cuckoo flax plant? Where does he live?

Kukushkin flax lives in coniferous forests and swamps. Its structure: stem, leaves. Cuckoo flax is called a gametophyte.

5. How is sphagnum different from cuckoo flax?

Cuckoo flax has green leaves, while sphagnum has light green leaves. Flax also has rhizoids and hairs, which are the roots with which the cuckoo flax hooks into the soil, extracting water from the soil and nutrients. Kukushkin flax is hard, unlike sphagnum, and it is less moisture-intensive.

6. Why is sphagnum also called peat moss? Tell us how peat is formed and how a person uses it?

Peat is formed from sphagnum. Sphagnum grows near swamps and when it dies, it settles to the bottom of the swamp and eventually rots.

7. Due to which thickets of cuckoo flax absorb and retain moisture well; sphagnum?

This is due to the structure of mosses. Mochime has hollow cells that are filled with air without moisture. If the moss is in humid conditions, then the water displaces the air, thus filling the space of these cells. These cells are dead and have a dense shell (so, when we take dry sphagnum, it is even very dense and rough). Therefore, due to the strength of these cells, moss can retain moisture for quite a long time.

8. What is the role of mosses in nature; human life?

Mosses are involved in the creation of special biocenoses. In nature, mosses absorb water. Sphagnum mosses are used as fuel or used in medicine. Mosses are also used in perfumery.

9. Prepare a report on how people used sphagnum moss in the past.

Used in beekeeping to collect excess moisture in the hive and in floriculture.

General characteristics of the department Bryophytes. Primitive structure, physiological processes, distribution of bryophytes. Distinguishing features of the classes.

Bryophytes, are quite large, numbering about 20 thousand species, division of the plant kingdom. Bryophytes are representatives of higher, or shoot, plants. This is the most primitive type in the category of higher plants.

Bryophytes have various adaptations to a terrestrial way of life, and at the same time, they have retained the features of aquatic plants.

In most cases, bryophytes are poorly adapted to living in dry places; they grow in an environment with high humidity - swamps, forests, damp meadows, where they often form a continuous cover. There are species that grow only in water. Mosses are autotrophic plants.

Unlike lower plants- algae and lichens - the body of most bryophytes is represented escape consisting of a stem and leaves; only in a part of the moss-shaped body is represented by a thallus (thallus).

Bryophytes also differ from lower plants in numerous microscopic features, including the presence of peculiarly arranged gametangia(genital organs): male - antheridium and women's archegonia.

Another distinguishing feature of bryophytes is the correct alternation in the normal cycle of plant development of two generations that are different in their morphology.

One generation is called gametophyte(a plant that produces sex elements - gametes), another - sporophyte(a plant that produces elements of asexual reproduction - spores).

The antheridium formed on the thallus or leaf-stem gametophyte has the appearance of a multicellular sac, inside which male gametes are formed - spermatozoa.

Archegonium has the appearance of a multicellular cone, in the expanded part of which - the abdomen of the archegonium - a female gamete is formed, or egg. If antheridia and archegonia are located on the same gametophyte, then such plants are called monoecious. If on one plant (male) antheridia are located, and on the other (female) - archegonia, then such species are called dioecious. There are also many-housed bryophytes, in which antheridia and archegonia can be located on the same and on different plants of the same species.

In the presence of drip liquid water the sperm reaches the egg and fertilizes it.

From the zygote resulting from fertilization, a sporophyte grows, which in bryophytes is called sporogony and which may consist of a foot. Sporogony initially develops in the abdomen of the archegonium, which, growing, turns into a cap. With the help of the foot, sporogony sucks water from the gametophyte with mineral salts and organic substances.

In the box of sporogony, a spore sac is formed, or sporangium. The ripe box is opened, and the spores enter the external environment.

Under favorable conditions, the spores germinate and give rise to a new gametophyte. In this case, a pregrowth, or protonema, is initially formed, which has the form of a multicellular thread, plate, spherical body, etc., and then grows gametophore- actually thallus or leaf-stemmed gametophyte, bearing gametangia, in which spermatozoa and eggs reappear, etc.

e. Thus, there is an alternation of generations in the life cycle of bryophytes.

Difference from higher plants: Differing in a number of features from lower plants, bryophytes stand apart among higher plants as well.

This predominance in the cycle of development of the sporophyte or gametophyte is reflected in the fact that in bryophytes we usually call the thallus or stemmed gametophyte, and in other higher plants the leafy sporophyte.

Bryophytes also differ from most other higher plants in the absence of roots and in some microscopic features.

Bryophytes can be divided into three classes: anthocerotes(Anthocerotae), liverworts (Neraticae) And mosses (Musci).

All three classes originated on Earth a very long time ago, about 300 million years ago, and since then have developed independently of one another, and therefore, along with common features indicating their origin from a common ancestor, these classes also have a number of specific features inherent only to them.

In general, among bryophytes (as well as among other higher plants), several ecological groups can be distinguished in relation to water:

hydrophytes live in water; they are attached by rhizoids to the trunks or branches of drowned trees or to underwater stones (for example, fire-fighting fontinalis - Fontinalis antipyretica) or float freely on the surface or in the thickness.

Hygrophytes- plants of excessively humid places (swamps, banks of rivers and streams, etc.);

P.); turfs and mats of hygrophytes, such as sphagnum, are usually saturated with pods for most of the year. Some plants can behave both as hydrophytes and as hygrophytes: for example, floating ricciocarp (Ricciocarpus iiatans) can float on the surface of the water or live on wet, muddy soil along the banks of a reservoir.

Mesophytes- plants living in places (often shady) with average moisture conditions (wet meadows, dark coniferous forests, etc.).

Role: Inconspicuous and unattractive at first glance, moss-shaped ones play a large and important role in life and nature. Capturing the energy of the Sun, releasing oxygen, participating in the circulation of matter and energy on Earth, bryophytes, like other plants, are an indispensable component of the Earth's biosphere, of which man is an integral part.

Able to tolerate extreme temperature fluctuations, excessive moisture or severe droughts, adapted to life on poor substrates, bryophytes form communities in places where higher vascular plants are oppressed or cannot exist at all.

Bryophytes are usually part of the primary plant groups on the surface of rocks and stones, they are often pioneers in the overgrowth of depressions filled with water and exposed soils. Gradually dying off, the pioneer species of bryophytes prepare the substrate for the settlement of other species of bryophytes or vascular plants.

Algae development cycles are very diverse, differ in great plasticity and are predetermined by many environmental factors.

1. The haplophase type is characterized by the absence of alternation of generations. The entire vegetative life of algae passes in a haploid state, i.e. they are haplonts. Only the zygote is diploid, the germination of which is accompanied by a reduction division of the nucleus (zygotic reduction). The algae that develop in this case are haploid.

   Examples are many green (volvox, most chlorococcal, conjugates) and char algae.

2. The diplophase type is distinguished by the fact that the entire vegetative life of algae is carried out in a diploid state, and the haploid phase is represented only by gametes.

   Before their formation, a reduction division of the nucleus occurs (gametic reduction). The zygote without nuclear division grows into a diploid thallus. These algae are diplonts. This type of development is typical for many green algae with a siphon structure, all diatoms and some representatives of brown algae.

3. The diplohaplophase type is characterized by the fact that in the cells of diploid thalli (sporophytes) of many algae, the reduction division of the nucleus precedes the formation of zoo- or aplanospores (sporic reduction).

   Spores develop into haploid organisms (gametophytes) that reproduce only sexually. A fertilized egg - a zygote - germinates into a diploid sporophyte, carrying organs of asexual reproduction. Thus, in these algae there is an alternation of developmental forms (generations): a diploid asexual sporophyte and a haploid sexual gametophyte.

   Both generations may not differ in appearance and occupy the same place in the development cycle (isomorphic change of generations) or sharply differ in morphological features (heteromorphic change of generations). An isomorphic change in generations is characteristic of a number of green (ulva, enteromorph, cladophora), brown and most red algae.

mosses in comparison with other higher plants, they are most primitively organized.

In the Bryophytes department, the sexual generation is developed - the gametophyte, which is primarily an adult moss plant.

The asexual generation (sporophyte) is represented in mosses by a sporogon (box on a stalk), which develops on the gametophyte after fertilization.

In lower mosses, there is no differentiation of the body into vegetative organs, and it is a flat leaf-shaped plate - thallus, lying on the soil or other substrate, attached to it by thin rhizoids.

The development of moss begins with a spore, i.e.

from a single-celled, microscopically haploid primordium.

Question:

After the spore hits a moist substrate, a thin, usually branched, green thread or plate of algae grows out of it. This small thread (plate) is called a protonema. After some time, buds appear on the protonema, giving rise to an adult moss plant. In real mosses, the stem (caulidia) and leaves (phyllidia) are clearly distinct from each other; the stem is most often covered with hairs or rhizoids in the lower part.

At the tops of the main stems or lateral branches, reproductive organs develop: antheridia ♂ archegonia ♀, in which germ cells are formed. Inside the antheridium, spermatozoa develop, while the archegonium contains the egg. All stages of moss development, starting with the spore and ending with the stem with leaves and genitals, are combined into the concept of the sexual generation or gametophyte.

Fertilization of an ovum by a spermatozoon is accomplished with the help of water droplets inside the archegonium in wet weather; after fertilization, a sporangium pod grows on the gametophyte, in which spores are formed after reduction division.

The box sits on a thin leg. This is the moss sporogon or asexual generation (sporophyte). By the time the spores ripen, the box opens at the top with a lid and the spores spill out.

Fern development cycle.

Sporophyte is the name of an adult leafy plant that forms significant thickets in temperate forests.

The sporophyte is the predominant generation of these plants. The next stage of the fern development cycle is the maturation of the organs of asexual reproduction. They are called sporangia. These structures look like small brown bumps located on the underside of the leaves. From above, they are additionally protected by membranous "spreaders". Fern sporangia are grouped into groups called sori. At the end of summer, these structures darken.

The result of the development of spores is a germ. This is the individual of the sexual generation, which is the next link in the fern development cycle.

Outwardly, it is a heart-shaped green plate. The growth develops on the soil, to which it is attached with the help of rhizoids. As the gametophyte develops, organs of sexual reproduction form on its underside.

Two types of sex cells mature in them: eggs and spermatozoa. Fertilization in ferns has its own characteristics. Firstly, male and female germ cells on the same growth mature at different times. Therefore, the fusion of gametes is possible only between different plants. This type of fertilization is called cross fertilization. The second feature of this process in ferns is the mandatory presence of water. The fact is that the germ cells of spore plants cannot move independently.

Therefore, the sperm can only get to the egg with the help of water. Thus, ferns, although they belong to the group of the first terrestrial plants, have not lost touch with their former habitat. Further, a plant of asexual generation develops from a fertilized egg, spores ripen on it, and the process is repeated.

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Differences between mosses and ferns:
1. Mosses do not have roots. Ferns have many adventitious roots growing from the rhizome (modified shoot).
2. Moss leaves are microscopic, fern leaves - fronds have a complex structure.

3. In mosses, the gametophyte is an adult leaf-stem plant, in ferns - a growth.
4. Mosses are haploid, ferns are diploid.
5. In mosses, photosynthesis is slow. Mosses can photosynthesize under snow. If the temperature of the cold season is close to 0, then the mosses remain evergreen.
6. Mosses - at an evolutionary dead end (the impossibility of reproduction without water).
7. The body of mosses can be represented by a thallus (no organs), as in the liverworts.

8. In mosses, tissues are poorly differentiated, in ferns, tissues are specialized.
9. In mosses, spores are in a box on a stalk, in ferns - on the back of the frond (on the sporophyte).
10. The life cycle of mosses runs inextricably from the gametophyte and sporophyte.

In ferns, the sexual generation is a separate independent plant (growth).
11. Some mosses can lead to waterlogging of their habitat.

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SIMILARITIES: these are the departments of HIGHER SPORING plants.

Which algae have rhizoids

Very ancient plants.
They gravitate towards humid environments.
There is a protonema stage in the life cycle, which indicates their common common ancestor.

Mosses and algae belong to the Plant Kingdom. Both classes were evolutionary stages that Flora had to go through in order to surprise a person with a giant sequoia, a blooming orchid, or a ruddy apple hovering over Newton.

mosses

mosses are representatives of higher spore plants, along with ferns, horsetails and club mosses.

None of the representatives of this group blooms, does not produce fruits or seeds. They reproduce asexually, producing spores, or sexually, but the fertilization process is possible only in the presence of a moist environment.

The most common representatives of mosses are cuckoo flax, sphagnum, polytrix hairy, brium, dikran and eriopus.

In the external structure of mosses, there is a difference between individuals of the sexual and asexual generation and individuals bearing male and female sex cells. Therefore, mosses are classified as dioecious plants.

Both female and male individuals have a stem, which is densely covered with leaves. The upper leaves are traditionally bright green in color due to the presence of chlorophyll, the lower ones are usually yellow-brown due to the destruction of the pigment in low light conditions. Mosses have no roots. They are attached to the ground by rhizoids, multicellular hair-like processes. Rhizoids anchor the plant in the soil and are involved in the absorption of nutrients by the moss.

Which algae have rhizoids

But the same nutrients can enter the plant through other organs.

On the tops of some mosses, you can see long thin processes, on top of which a box with a lid is held. These are individuals of the asexual generation that have developed from a fertilized egg. Over time, they lose their green color and the ability to photosynthesize, so they feed on the individual of the sexual generation.

A box with a lid - sporangium, after the spores in it mature, opens. If the spores get into a highly moistened soil, then they germinate in the form of a green thread, similar to filamentous algae. Such a "thread" grows, and individuals of the female and male sexual generation are formed from some of its cells. Despite the alternation of generations, the sexual generation predominates in the life cycle of mosses.

Mosses are considered the pioneers of the terrestrial space; they are common in almost all natural areas of the land, as well as in the shallow waters of fresh water bodies.

Mosses regulate the water regime of soils, stimulating their waterlogging. Sphagnum moss is the main plant that forms peat, and is also one of the oldest dressing materials due to its bactericidal properties.

Seaweed

Seaweed- the very first and ancient representatives of the plant kingdom. There are about 50 thousand species of these organisms. Among them there are unicellular, multicellular and colonial species.

In the cells of all algae there are plastids of green, brown, red color, which determines the taxonomic affiliation of the plant.

A feature of algae is "binding" to the aquatic environment - to freshwater or salty reservoirs. But there are specimens that live in Antarctica on the snow, on the wool of sloths in South America, or enter into symbiosis with fungi, forming lichens.

Algae can reproduce sexually, asexually, or vegetatively using broken portions of the thallus.

In brown and red algae, collections of cells are observed that perform the same functions as the tissues of higher plants.

Algae enrich the reservoir and atmosphere with oxygen, produce a lot of organic matter and play a role in the formation of sedimentary rocks and soil. Algae are fed to pets, used as fertilizer, confectionery, medicine, or used as a natural water purifier.

Conclusions TheDifference.ru

1. Mosses are more complexly organized than algae.
2. Algae appeared much earlier than mosses.
3. Among the algae there is a large group of unicellular, all mosses are multicellular organisms.
4. Most algae live in the aquatic environment, most mosses live on land, but with a high percentage of humidity.
5. The body of moss is differentiated into organs; only in the most developed algae can one observe the prototype of tissues.
6. Mosses have external differences between males, females, between sexual and asexual generations.

   In algae, all individuals of the same species are the same.

7. Mosses cannot reproduce vegetatively, but algae can.