1. What parts does a moss body consist of? Compare the structure of mosses and multicellular algae.
Moss is composed of leaves and stems, then its main organs and tissues.
Moss and multicellular algae have rhizoids, this is their main similarity.
2. How do mosses attach to the soil if they have no roots?
It is attached to the soil and other places where moss lives with the help of rhizoids, which resemble thin threads.
3. What is the important condition for the existence of mosses?
The main thing is that there is moisture and water; without water, moss cannot 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 gametophyte.
5. How is sphagnum different from cuckoo flax?
Cuckoo flax has green leaves, while sphagnum leaves are light green. Flax also has rhizoids and hairs, which are the roots by which cuckoo flax catches on to the soil and extracts water from the soil and nutrients. Kukushkin flax is hard, unlike sphagnum, and it is less water-absorbing.
6. Why is sphagnum also called peat moss? Tell us how peat is formed and how people use it?
Peat is formed from sphagnum. Sphagnum grows near swamps and when it dies, it sinks to the bottom of the swamp and eventually decays.
7. Due to this, cuckoo flax thickets well absorb and retain moisture; sphagnum?
This is due to the structure of mosses. Mocheetes 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 (for example, 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 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 medicinally. 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. Distinctive features of the classes.
Bryophytes are rather large, numbering about 20 thousand species, department of the plant kingdom. Bryophytes are representatives of higher, or shoot, plants. It is the most primitive type in the higher plant category.
Bryophytes have various adaptations to a terrestrial lifestyle, and at the same time, they retain 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 only grow in water. Mosses are autotrophic plants.
Unlike lower plants - algae and lichens - the body of most bryophytes is represented escapeconsisting of stem and leaves; only part of the moss-shaped body is represented by the thallus (thallus).
Bryophytes also differ from lower plants in numerous microscopic features, including the presence of peculiarly arranged gametangiev (genitals): male - antheridium and women - archegonia.
Another distinctive feature of bryophytes is the correct alternation in the normal cycle of plant development of two generations that are different in their morphology.
One of the generations 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 form of a multicellular sac, inside which male gametes are formed - sperm.
Archegonium has the form of a multicellular cone, in the expanded part of which - the abdomen of archegonia - a female gamete is formed, or egg... If antheridia and archegonia are located on the same gametophyte, then such plants are called monoecious... If antheridia are located on one plant (male), and archegonia on the other (female), then such species are called dioecious. There are also multi-house bryophytes, in which antheridia and archegonia can be located on the same and on different plants of the same species.
In the presence of droplet liquid water the sperm reaches the egg and fertilizes it.
From the zygote resulting from fertilization, a sporophyte grows, which is called sporogony and which may consist of a foot. Sporogonia initially develops in the abdomen of archegonia, which, expanding, turns into a cap. With the help of the foot, the sporogony sucks water from the gametophyte with mineral salts and organic substances.
Sporogony forms a spore sac in the capsule, or sporangium. The ripe capsule is opened, and the spores enter the external environment.
In the presence of favorable conditions, the spores germinate and give rise to a new gametophyte. In this case, a pre-growth, or a pro-toneme, is initially formed, which has the form of a multicellular filament, plate, spherical body, etc., and then it already grows gametophore- the actual thallus or leaf-stem gametophyte, bearing gametangia, in which spermatozoa and egg cells reappear, etc.
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, moss-different stand apart among higher plants.
This predominance in the development cycle of the sporophyte or gametophyte is reflected in the fact that in bryophytes we usually call the layered or unstable gametophyte, and in the rest of the 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: anthocerotic(Anthocerotae), liverworts (Herat) and mosses (Musci).
All three classes originated on Earth long 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 pitfalls (for example, fire-fighting fontinalis - Fontinalis antipyretica) or float freely on the surface or in the thickness.
Hygrophytes - Plants in excessively humid places (swamps, river banks and streams, etc.)
p.); tufts and rugs of hygrophytes, such as sphagnum, are usually soaked in milk 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 in moist muddy soil along the banks of the reservoir.
Mesophytes- plants that live in places (often shady) with medium moisture conditions (wet meadows, dark coniferous forests, etc.)
Role: Unobtrusive 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 the Earth, bryophytes, like other plants, are an irreplaceable component of the Earth's biosphere, of which man is an integral part.
In nature: · Are the pioneers of the settlement of uninhabited substrate. · Participate in the creation of special biocenoses, especially where the soil is almost completely covered (tundra).
|
In human activities: · May worsen the productivity of agricultural land, contributing to their waterlogging. § 18. Algae
|
Capable of tolerating 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 found in the primary plant groupings on the surface of rocks and stones, and they are often the pioneers of overgrowing depressions filled with water and exposed soils. Gradually dying off, pionerous species of bryophytes prepare a substrate for the settlement of other species of bryophytes or vascular plants.
Algae development cycles are very diverse, differ in great flexibility and are predetermined by many environmental factors.
- The haplophase type is characterized by the absence of alternation of generations. All vegetative life of algae takes place in a haploid state, i.e. they are haplonts. Only the zygote is diploid, the germination of which is accompanied by reduction fission of the nucleus (zygotic reduction). The algae developing at the same time turn out to be haploid.
An example is many green (volvox, most chlorococcal, conjugates) and charoe algae.
- The diploid type differs in 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, there is a reduction division of the nucleus (gametic reduction). A zygote without nuclear division grows into a diploid thallus. These algae are diplants. This type of development is characteristic of many green algae with a siphon structure, all diatoms and some representatives of brown ones.
- 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 (spore reduction).
Spores develop into haploid organisms (gametophytes) that reproduce only sexually. A fertilized ovum - a zygote - grows into a diploid sporophyte, which carries the organs of asexual reproduction. Thus, these algae have an alternation of developmental forms (generations): diploid asexual sporophyte and haploid sexual gametophyte.
Both generations by appearance may not differ and occupy the same place in the development cycle (isomorphic alternation of generations) or differ sharply in morphological characteristics (heteromorphic generation change). Isomorphic alternation of generations is characteristic of a number of green (ulva, enteromorph, cladophore), brown and most red algae.
Mossesin comparison with other higher plants, they are most primitively organized.
In the Department of Mossy, a sexual generation is developed - the gametophyte, which is primarily an adult moss plant.
The asexual generation (sporophyte) is represented in mosses by sporogon (box on a leg), which develops on the gametophyte after fertilization.
In lower mosses, the body does not differentiate 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.
Moss development begins with a spore, i.e.
from a unicellular, microscopically haploid primordium.
Question:
After the spore hits a wet substrate, a thin, usually branched, green thread or plate of algae grows out of it. This small thread (plate) is called a protonema. After a while, buds appear on the protoneme, giving rise to an adult moss plant. In true mosses, the stem (caulidia) and leaves (phyllidia) are clearly distinguished from each other; the stem most often in the lower part is covered with hairs or rhizoids.
On the tops of the main stems or lateral branches, the genitals develop: antheridia♂ archegonia♀, in which the sex cells are formed. Sperm develop inside the antheridium, while the archegonium contains an egg cell. All stages of development of moss, from the spore to the stem with leaves and genitals, are combined into the concept of a sexual generation or gametophyte.
Fertilization of an egg by a sperm cell is carried out with the help of water droplets inside the archegonia in wet weather; after fertilization, a capsule with a sporangium grows on the gametophyte, in which spores form after reduction division.
The box sits on a thin leg. This is a moss sporogon or asexual generation (sporophyte). By the time the spores mature, the capsule opens with a lid at the top and the spores spill out.
Fern development cycle.
Sporophyte is the name of an adult leafy plant that forms significant thickets in temperate forests.
Sporophyte is the predominant generation of these plants. The next stage in the fern development cycle is the maturation of the organs of asexual reproduction. They are called sporangia. These structures appear as small brown bumps located on the underside of the leaves. From above they are additionally protected by membranous "covers". Fern sporangia are collected in groups called sori. At the end of summer, these structures darken.
The result of the development of spores is an outgrowth. This is an individual of the sexual generation, which is the next link in the fern development cycle.
Outwardly, it is a heart-shaped green plate. The germ develops on the soil, to which it attaches with the help of rhizoids. As the gametophyte develops, the organs of sexual reproduction are formed on its underside.
Sex cells of two types mature in them: eggs and sperm. Fertilization in ferns has its own characteristics. Firstly, male and female reproductive cells on the same germ 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, although ferns belong to the group of the first land plants, they have not lost their connection with the previous habitat. Further, a plant of an asexual generation develops from a fertilized egg, spores ripen on it, and the process is repeated.
Social buttons for Joomla
Do algae have roots?
Plant anatomy and morphology
Dictionary of botanical terms
Natural science. encyclopedic Dictionary
They have a simpler structure than the roots of higher plants ...
Geological encyclopedia
Great Soviet Encyclopedia
Big encyclopedic dictionary
Russian spelling dictionary
Spelling dictionary of the Russian language
Efremova's explanatory dictionary
Dictionary of foreign words of the Russian language
Reply left a guest
DIFFERENCES between mosses and ferns:
1. Mosses have no roots. Ferns have many adventitious roots that grow from the rhizome (modified shoot).
2. Leaves of mosses are microscopic, leaves of ferns - frond have a complex structure.
3. In mosses, the gametophyte is an adult leafy plant, in ferns, an outgrowth.
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 are in an evolutionary dead end (impossibility of reproduction without water).
7. The body of mosses can be represented by a thallus (no organs), as in the Liverwort.
8. In mosses, tissues are poorly differentiated, in ferns, tissues are specialized.
9. In mosses, spores are in a box on a leg, in ferns - on the back of the frond (on sporophyte).
10. The life cycle of mosses is inseparable from gametophyte and sporophyte.
In ferns, the sexual generation is a separate independent plant (germ).
11. Some mosses can lead to waterlogging of their habitat.
——————————————
SIMILARITIES: these are the divisions of HIGHER SPORAL plants.
Which algae have rhizoids
Very ancient plants.
They gravitate towards a humid habitat.
There is a protoneme stage in the life cycle, which indicates their common common ancestor.
Mosses and algae belong to the plant kingdom. Both classes were evolutionary steps 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
Mossesare representatives of higher spore plants, along with ferns, horsetails and lyre.
None of the representatives of this group blooms, does not produce fruits or seeds. They reproduce asexually, producing spores, or sexually, but the process of fertilization is possible only in the presence of a moist environment.
The most common representatives of mosses are cuckoo flax, sphagnum, hairy polytrix, brium, dikran and eriopus.
In external structure mosses, there is a difference between individuals of the sexual and asexual generation and individuals carrying male and female germ cells. Therefore, mosses are classified as dioecious plants.
Both females and males have a stem that is densely covered with leaves. The upper leaves are traditionally bright green due to the presence of chlorophyll, the lower ones are usually yellow-brown due to the destruction of the pigment in low light conditions. Moss has no roots. They are attached to the ground by rhizoids, multicellular hair-like processes. Rhizoids anchor the plant in the soil and participate 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 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.
The box with a lid is a sporangium, after the spores in it mature, it opens. If the spores get into a highly moist soil, they germinate in the form of a green thread, similar to filamentous algae. Such a "thread" grows, and from some of its cells individuals of the female and male sexual generations are formed. Despite the alternation of generations, the sexual generation predominates in the life cycle of mosses.
Mosses are considered the pioneers of terrestrial space, they are common in almost all natural areas land, as well as in shallow fresh water bodies.
Mosses regulate the water regime of soils, stimulating their waterlogging. Sphagnum moss is the main peat-forming plant and is also one of the oldest dressings for its bactericidal properties.
Seaweed
Seaweed- the very first and most 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 belonging of the plant.
The peculiarity of algae is the "binding" to the aquatic environment - to freshwater or salt reservoirs. But there are specimens that live in Antarctica in the snow, on the fur of sloths in South America, or enter into symbiosis with mushrooms, forming lichens.
Algae can reproduce sexually, asexually, or vegetatively using torn sections of the thallus.
In brown and red algae, assemblies of cells are observed that perform the same functions as tissues of higher plants.
Algae enrich the reservoir and the atmosphere with oxygen, produce a lot of organic matter and take a role in the formation of sedimentary rocks and soil. Algae is fed to pets, used as fertilizer, made confectionery, medicine, or used as a natural water purifier.
Conclusions TheDifference.ru
- Mosses are more complexly organized than algae.
- Algae appeared much earlier than mosses.
- Among the algae there is a large group of unicellular organisms, all mosses are multicellular organisms.
- Most algae live in an aquatic environment, most mosses live on land, but with a high percentage of moisture.
- The moss body is differentiated into organs, only in the most developed algae it is possible to observe the prototype of tissues.
- Moss has external differences between males, females, between sexual and asexual generations.
In algae, all individuals of the same species are the same.
- Mosses cannot reproduce vegetatively, but algae can.
Each 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. Lower organisms such as mosses, lichens, and algae cannot boast high level development, which means that their body is much simpler. For example, rhizoids perform the functions of roots. 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 function as a root. They are often colorless, short (their length may be limited to a few millimeters) and not very strong.
What are the differences between root and rhizoids?
- There are no conductive tissues in the rhizoids. Osmosis and water intake into the body is one of the most important functions of the plant roots. If there are no xylem and phloem in underground structures, they cannot be considered true roots.
- There is a big difference in the dimensions of the roots and rhizoids. While the former can reach tens of meters in length and meters in width, the rhizoids are small, sometimes even microscopic formations.
- 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 their functions.
However, one similarity can be seen right away: both the root and the rhizoids perform the function of anchoring - keeping the plant's body in the soil. But even here we can make a reservation that the root copes with this function much more efficiently than rhizoids.
And yet, rhizoids are a kind of precursor to 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 fauna, and also attract the interest of botanists. This is what rhizoids are in biology.
Functions of rhizoids
The significance of these structures in biology is not limited to their 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:
- Retention of the main part of the plant in the soil or at the bottom of the reservoir, when it comes to algae.
- Gas exchange and soil loosening.
- Avoid the ingress of excess water, too large drops of moisture.
- Water absorption.
These are the most general functionsthat can carry the rhizoids of algae and mosses.
Types of rhizoids
Not all underground structures of mosses and algae are alike. Even among such simple formations, specialization is observed depending on the function and structure. What are rhizoids and what are they in nature?
Rhizoids can be smooth (simple) and ligulate. The former are ordinary underground structures that serve to attach, stabilize the plant and keep it still.
Reed rhizoids differ in that their diameter is slightly smaller, the walls are thinner and wavy. Inside such formations, there are outgrowths that resemble papillae or tongues, which is where their name comes from. The function of such rhizoids is the flow of water by the capillary method, which is facilitated by such an unusual shape.
Also, when studying "felt" from rhizoids, one can find intermediate variants of these structures, which have incorporated the features of both smooth and reed analogs. This is what rhizoids are in terms of the variety of structures.
In what organisms can rhizoids be found?
Previously, mosses and algae belonged to the lower plants, since their structure was evolutionarily less developed than that of spore and seed plants. All representatives of the lichen kingdom also have rhizoids, since this organism is a symbiotic relationship between algae and fungi. By the way, some representatives of fungi also form rhizoids.
Not all mosses have these underground structures. For example, sphagnum, which lives in wetlands, absorbs water over the entire surface of the body, respectively, in this case, the formation of rhizoids is not necessary. The same situation is with all sphagnum mosses.
What is the difference between rhizoids and rhizomoids?
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 advanced organisms than mosses or algae.
Rhizomoids are the precursor of ferns and lyre rhizomes. They are formed by the interlacing 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 rhizomoids.
what are rhizoids what functions do they perform and got the best answer
Answer from
Rhizoids (from the Greek rhíza - root and éidos - species), 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 water and nutrients. In appearance, R. resemble root hairs. Marshall mosses have special, so-called reed, R., consisting of dead cells, along which water moves, as if along a wick.
The rhizoid is an organ that replaces the root in those lower-organized plants (stratus) that do not have real roots. Morphologically, it is most reminiscent of root hairs, from which in the simplest cases (liver mosses, fern sprouts) it differs almost only by the presence of a septum at the base, and, therefore, is a highly elongated cell that serves to absorb nutrients from the soil. More completely educated, leaf mosses are a complex system of branching, and the diameter of the branches is constantly decreasing, so that in general, such R. is quite reminiscent of a real root, only in a small form. They also 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 filaments with which mosses, lichens, algae and fungi attach to the surface and receive moisture and nutrients. In essence, rhizoids are the prototypes of the roots that plants have. Strictly speaking, the very word rhizoids means in translation "tapered". In the process of development of life on Earth, mosses, algae, fungi and lichens first appeared, which had rhizoids instead of roots, and then higher plants, in which rhizoids developed into full-fledged roots.
The functions of rhizoids, like roots, are to attach to a surface and receive 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 the Greek rhiza - root and eidos - species), filamentous formations of one or more cells arranged in a row, in mosses, lichens, some algae and fungi (for example, in Rhizopus), serving to attach to the substrate and absorb from water and nutrients. In appearance, R. resemble root hairs. Marshall moss has special, so-called reed, R., consisting of dead cells, along which water moves, as if along a wick.
These are filamentous formations in mosses, fern sprouts, lichens, some algae and fungi that perform the function of a root.
The rhizoid is an organ that replaces the root in those lower-organized plants (stratus) that do not have real roots. Morphologically, it is most reminiscent of root hairs, from which in the simplest cases (liver mosses, fern sprouts) it differs almost only by the presence of a septum at the base, and, therefore, is a highly elongated cell that serves to absorb nutrients from the soil. More completely educated, leaf mosses are a complex system of branching, and the diameter of the branches is constantly decreasing, so that in general, such R. is quite reminiscent of a real root, only in a small form. They also differ from root hairs in that they are sensitive to light and gravity, which makes them closer to real roots.