Anyone who has even a little touch on issues of botany, had heard about such a delimitation of plants like flowering and cryptogamic.At the same time the latter have yet another name that reflects the essence of their way of reproduction - spore.What plants are called spore?Those for breeding and spread their seeds have chosen the most ancient in evolutionary terms the way - the formation of tiny, diverse forms of the structure - the dispute.
What plants are called spore?
To answer this question as fully as possible, start with a definition of the dispute (in Greek spora - "seed", "seed", "sowing").This fine structure is not larger than 1 micron (3.10 millimeter), varied in shape and color, which plays a role in all the seed spore, giving rise to the development of the embryo of the future plant.
Generate disputes - is not the prerogative of all kinds of currently existing plants.It is believed that this ability came to the representatives of all the flora from the distant past, when there were just beginning to appear the first land plants, in addition to water and life originated on land.
known that the oldest plants are algae, horsetails, club mosses and ferns.It is their historical roots in such periods as the Cretaceous, Silurian and Carboniferous.And they still are inhabitants of forests, plains, swamps, steppes and the polar region from different continents.
Such a long life for them was possible, in part, because they just relate to the spore.Therefore, the question of what is called the spore plants, we can give a definite answer.It ferns, mosses, club mosses, horsetails (from highest category), as well as algae and lichens from the category lower.
distinctive features
The main feature that distinguishes all spore plants include the following:
- With the formation of structures such as spores, these plants will never form a color (this is not biologically adapted).Therefore, all the myths about the lush fern on the night of Ivan Kupala - just a fairy tale.
- life cycle of these plants has its own characteristics.Spore plants have alternation of generations in the life cycle.So, gametophyte - sexual generation, formed by the confluence of the sperm (antheridium) and eggs (archegonium) - over time forms the adult plant, which produces spores.Because the spores germinate sporophyte - asexual generation, which forms a small controversy in special structures and gives rise to the new plant.Such a change in sexual and asexual generation accompanies spore plants throughout the period of their existence.
- for breeding they necessarily need water.That liquid sperm gets to archegonium in which the egg is hidden.Without water, the process of fertilization in spore impossible.This is another proof that it is the most ancient flora, whose life has always been closely linked to water.It was from there and have their origin in all plants.
These are the main features that distinguish the spore-plants from seed.Now consider the details of the main representatives of nadotdela.
Ferns Ferns - most commonly known as decorative purposes, and the historical understanding of ancient flora spore plants.Examples of plants known to all gardeners, nature lovers and solitude of the forest.Bracken, athyrium, strausnik - smart in terms of the plants that attract the splendor and rich green foliage.They are ubiquitous in forest areas in areas with a temperate climate and high humidity.
Anyone who loves pets Pot flowers, probably also at or seen others Nephrolepis - the most common room fern.In addition to the external beauty of these plants is quite undemanding and require only an abundant and continuous irrigation.Like all spore, they can not reproduce without water.
on fern leaves very visible sporangia with spores.They are located on the back of the fronds (leaves) and look like small round sacs brown or dark orange.They fine yellow powder sprinkled thickly disputes.After a maturation revealed sporangia and spores poured into the environment.
Total ferns there are more than 10,000 species, united in 300 genera.
Mosses
Very interesting and beautiful plants that form this litter, like a carpet - mosses.Spore plants that have a very small structures - stem, leaves, stem from the sporangium a box - it's all about them.Therefore, there are few who differ in appearance, except that the real experts on the mosses.
color of these plants are rich, lush green leaves are tough, small, wedge-shaped.Although there are other forms, depending on the species of moss.The main groups at the moment following:
- politrihovye;
- brievye;
- hypnum;
- sphagnum.
Total mosses there are about a hundred species, so this list includes only the most common, and have practical value.
interesting feature of these plants is that they resemble sporangia cups with caps of different shapes.When the spores mature, lid open, and the stalk, which is located at the top of sporangia, bends, and disputes poured out.
Algae Algae - spore plants, numbering today nearly a hundred species, united in 11 major departments.The main distinguishing feature of the flora - life in the aquatic environment at a very different depths.Their body represented thallus, it has no leaves and roots.The function of the latter in these plants operate semi-prehensile hooks, bearing the name of the rhizoids.
Algae are lower plants because of the lack of division of the body organs.They also multiply by spores.The main four sections of algae, which are the most widespread and useful in practical human activity, the following:
- Green.
- Brown.
- Red.
- Diatoms.
horsetail ferns With this group of spore-bearing plants are populated once the entire land, but gradually went on the formation of deposits of peat and coal.Today, horsetails represented by a small number of species - they are about thirty.
most common in Russia - horsetail.He looks like a low plant with stiff erect stem, divided into small segments interstices of which are located bunches of leaves, similar to the needle.Overall, therefore, horsetail resembles a small Christmas tree.
Separation body into small segments - a distinctive feature of all these species of flora.Propagated horsetail, other spore plants, using a generational change, that is, and asexually (spores), and sex (sperm and eggs).
moss
interesting group of marsh plants that are different from all other spore their appearance.They have beautiful, dotted with small leaves stems.Each of them seemed to spread along the ground.
There are about forty-five species of moss.Plant biology is no different from that of the already discussed earlier spore.They also have a life cycle shift sporophyte and gametophyte, depend on water, so only grow in swampy and very wet soils.Their sporangia are small dense elongated structure.After maturation of the dispute they burst, and disputes go outside.
Lichens
about 26 thousand species of these plants, united in 400 births, has modern biology.These plants are different from all the other features of the structure and way of life.The fact that they are the product of close mutually beneficial cooperation and partnership between the two kinds of living creatures - single-celled algae and fungi.
Such symbiosis has several advantages:
- tolerance to temperature fluctuations (lichens can survive under extreme Arctic);
- continuous exchange of nutrients (organic seaweed gives the fungus and the fungus it - minerals);
- adaptability to various soils.
why lichens are though lower spore plants, however, have undoubted advantages over higher in terms of lifestyle.
Phylogeny
It spore plants from the beginning of its existence the modern flora of our planet.For a number of theories that life originated in the ocean.There arose the first plants that were lower spore - algae.Gradually, they move to the land, they have formed leaves and roots to hold the soil.However breeding was still need water.
then algae gave rise to the ancient ferns, horsetails, mosses and moss that the process of dying in a few million years, a whole mineral deposits.If the ancestral forms of spore-bearing plants were wood structure, the current does not have any relation to the trees.
whole process described phylogeny of flora took about four hundred million years.Now, however, a general description of spore plants enables them to allocate nadotdel, has not lost a final communication with the ancestors (for reproduction still need water), but already formed and having new signs.
Applications in everyday life
Feature spore plants allows us to understand that they are not such a global practical importance, as the flowering.However, the scope of their use are numerous:
- Wood spore plants form mid selura and Carboniferous formed a huge coal deposits, which people use to this day.
- Young shoots of ferns can be eaten.
- Different parts of horsetail plants and ferns are used in medicine as an analgesic, diuretic, astringent, anti-inflammatory and other means.
- club mosses are very fine and soft texture of disputes that can be used as baby powder.
Thus, we have a full and detailed answer to the question of what is called the spore plants.
