Anyone who has even a little concerned questionsbotanists have heard of such a distinction between plants as flowering and non-flowering. At the same time, the latter have another name, reflecting the essence of their mode of reproduction, - spore ones. What plants are called spore plants? Those who chose to propagate and spread their seeds chose the most ancient evolutionary method — the formation of tiny structures of various forms — spores.
What plants are called spore plants?
To answer this question as completely as possible, let's start with the definition of the dispute itself (translated from the Greek spora - "seed", "seed", "sowing"). This is a small structure no larger than 1 micron (10-3 millimeter), diverse in shape and color, which plays the role of a seed in all spore, giving rise to the development of the embryo of the future plant.
Shaping controversy is not a prerogative of allspecies of plants currently existing. It is believed that this ability in general came to the representatives of the flora from the distant past, when the first land plants were just beginning to emerge, and life besides water originated on land.
It is known that the most ancient plants arealgae, horsetails, moss and ferns. It is their historical roots that go back to periods such as Cretaceous, Carboniferous, and Silurian. And it is they who today are residents of forests, plains, marshes, steppes and the polar region of different continents.
Such a long existence has become for thempossible, in part, because they belong to the dispute. Therefore, the question of what plants are called spore plants, we can give a definite answer. These are ferns, mosses, moss, horsetails (from the category of higher), as well as algae and lichens from the category of lower ones.
Distinctive features
The main features that distinguish all spore plants include the following:
- Due to the formation of structures such as disputes,these plants never form flowers (they are not biologically adapted to this). Therefore, all the myths about the flowering fern on the night of Ivan Kupala are just fairy tales.
- Жизненный цикл данных растений имеет свои features Spore plants are distinguished by alternating generations in the life cycle. Thus, the gametophyte — the sexual generation that forms when a sperm cell (antheridium) and an egg cell (arhegonium) merge — eventually forms an adult plant that produces spores. A sporophyte sprouts from a spore - asexual generation that forms small spores in special structures and gives rise to a new plant. Such a change of sexual and asexual generation accompanies spore plants throughout the entire period of their existence.
- For reproduction, they necessarily need water.It is through the fluid that the sperm reaches the archegonies in which the egg cell is hidden. Without water, the fertilization process in the spore is impossible. This is another proof that these are the most ancient representatives of the flora, whose life has always been closely associated with the aquatic environment. It is from there that all plants originate.
These are the main features that distinguish spore plants from seed. Now let's take a closer look at the main representatives of this department.
Ferns
Ferns are most commonly known asdecorative purposes, and in historically established ideas about the ancient flora of spore plants. Examples of plants are known to all amateur gardeners and lovers of nature and forest retreat. Orlyak, nomad, ostrich - chic in size plants that attract the pomp and richness of green foliage. They are ubiquitous in forest areas in areas with a temperate climate and high humidity.
One who loves home potted flowers,probably also has or has seen nephrolepis in others - the most common indoor fern. In addition to the external beauty of such plants are quite unpretentious and require only abundant and constant watering. Like all spore ones, they cannot reproduce without water.
On the leaves of ferns are very clearly visiblesporangia with spores. They are located on the back of the frond (leaf) and have the appearance of small rounded pouches of brown or dark orange color. Spores are thickly poured into them with fine yellow powder. After maturation, the sporangia opens, and spores are poured into the external environment.
There are more than 10 thousand species of ferns, united in 300 genera.
Mosses
Very interesting and beautiful plants that formreal forest flooring, like a carpet, is mosses. Spore plants that have very small structures — a stem, leaves, a stalk with a sporangium in the form of a box — it's all about them. Therefore, few of them are distinguished by their appearance, except that the real experts on mosses.
The color of these plants is saturated, juicy green, the leaves are stiff, small, wedge-shaped. Although there is another form, it depends on the type of moss. The main groups at the moment are as follows:
- polytric;
- briyevy;
- hypnosis;
- sphagnum.
In total, there are about a hundred moss species, so the list includes only the most common and of practical importance.
An interesting feature of these plants isthat their sporangia resemble mugs with caps of various shapes. When the spores mature, the cap opens, and the stalk, at the top of which the sporangium is located, bends, and the spores spill out.
Seaweed
Algae - spore plants counting onToday, about a hundred species, united in 11 main divisions. The main distinguishing feature of these representatives of the flora is life in the aquatic environment at the most diverse depths. Their body is represented by thallus, it has no leaves and roots. The function of the latter in these plants is performed by translucent, tenacious hooks, called rhizoids.
Algae belong to the lower plantsdue to the lack of division of the body into organs. They also multiply disputes. The four main divisions of algae, which are most widespread and applicable in human practice, are the following:
- Green.
- Brown.
- The Reds.
- Diatoms.
Horsetails
Вместе с папоротниками эта группа споровых plants once inhabited the entire land, but gradually went to the formation of deposits of peat and coal. Today, horsetails are represented by a small number of species - there are about thirty of them.
The most common in Russia is horsetail.It has the appearance of a low plant with a rigid, erect stem, divided into small segments by interstices, from which bundles of leaves resembling needles emerge. Therefore, in general, horsetail resembles a small Christmas tree.
Dividing the body into small segments isdistinctive feature of all these representatives of flora. Horsetail breeds, like other spore plants, by means of a change of generations, that is, asexually (by spores), and sexual (by spermatozoa and ova).
Moons
An interesting group of marsh plants, which differ from all other spore plants in their appearance. They have beautiful stalks dotted with small leaves. Each of them as if spread along the ground.
In total, there are about forty-five types of moss.The biology of the plant is no different from that in the previously discussed spore ones. They also have in the life cycle a change of sporophyte and gametophyte, they depend on water, therefore they grow only on swampy and very wet soils. Their sporangia are small, dense, elongated structures. After the spores mature, they burst, and the spores come out.
Lichens
Approximately 26 thousand species of these plants,united in 400 genera, includes modern biology. These plants are different from all other features of the structure and lifestyle. The fact is that they are a product of close mutually beneficial cooperation, partnership between two types of living beings - unicellular algae and fungi.
This symbiosis has several advantages:
- tolerance to temperature fluctuations (lichens are able to survive in the conditions of the extreme polar region);
- constant exchange of nutrients (the alga gives away the fungus organic, and the fungus gives it minerals);
- adaptability to different soils.
Therefore, lichens are, albeit lower spore plants, but they have undoubted advantages over higher ones in terms of lifestyle.
Phylogenesis
It is from spore plants that began itsexistence is the modern flora of our planet. According to a number of theories, life originated in the ocean. In the same place, the first plants, which were the lowest spore ones, appeared - the algae. Gradually, they moved to the land, they formed leaves and roots to hold in the soil. However, water was still needed for reproduction.
Then the algae gave rise to the ancient ferns,horsetails, mosses and morass, which in the process of dying for several million years, formed the entire deposits of minerals. If the ancestral forms of spore plants had a woody structure, then modern ones have nothing to do with trees.
Весь процесс филогенеза описываемых representatives of the flora took about four hundred million years. However, now the general characteristic of spore plants allows them to be distinguished in a super-department that has not yet lost its final connection with the ancestors (water is still needed for reproduction), but already formed and having new features.
Application areas in everyday life
The characteristic of spore plants allows to understand that they have not such global practical value as flowering ones. However, the spheres of their use are numerous:
- The woody forms of the spore plants of the middle of Selur and the Carboniferous period formed huge deposits of coal, which man still uses.
- Young shoots of ferns can be eaten.
- Different parts of the plants of the horsetail and fern are used in medicine as painkillers, diuretics, astringents, anti-inflammatory and other means.
- Moons have very small and soft-textured spores that can be used as baby powder.
Thus, we received a complete and detailed answer to the question of which plants are called spore plants.
