Plutos, horsetails, ferns represent a group of the first terrestrial plants. Despite the fact that they arose more than 400 million years ago, these plants have become widespread in the modern period. The structure of club mosses, horsetails and ferns, the features of their vital activity and biological significance will be discussed in our article.
Growing plants on land
There is a theory that all living organisms, including plants, originated in the aquatic environment. The first of these were algae. Over time, environmental conditions have changed significantly, and algae have had to adapt to endure long periods of drought. As a result, they gave rise to the first land plants. Even in the school botany course, ferns, horsetails, club mosses (grade 6) are considered land-dwellers.
An extinct group of the first terrestrial plants are representatives of the department of rhinophytes. Their low shoots were devoid of leaves andbranched forked. And instead of roots, rhinophytes had rhizoids, with the help of which they attached to the substrate.
Plutos, horsetails, ferns - higher spore plants
Modern spore plants have a more complex and perfect structure. Club mosses, horsetails, ferns, like all representatives of this systematic group, are formed by real tissues. Thanks to their appearance, the emergence of plants on land became possible. Tissues form organs: root and shoot. This is their main difference from lower plants, which consist of non-specialized cells.
Reproduction of these organisms occurs with the help of cells of asexual reproduction - spores. Once in the soil, they germinate.
Life cycle concept
All higher spore plants have a complex life cycle. This is the period between two identical phases of development. It is he who ensures the continuity of life of a certain biological species. In the life cycle of spore plants, there is an alternation of generations - sexual and asexual. Sometimes they differ from each other in appearance.
The plant that produces spores is an asexual generation. It is predominant in mosses. An individual of the sexual generation grows from the spore - the gametophyte. The main difference between club mosses, horsetails and ferns lies in its predominance.
Let's consider each of the departments of higher spore plants in more detail.
Department of lycopsids
It's evergreenherbaceous plants that grow in damp places. In most cases, they are perennial. Club mosses have creeping stems that branch forked. Small leaves are attached to them in a spiral.
The root system is formed by additional roots extending directly from the stems. In the area of the tops of the shoots there are scales, which are modified leaves. They are the organs of asexual reproduction - sporangia.
Features of the structure of horsetails
Modern species of horsetail are also perennial herbaceous plants. Their characteristic feature is a clear division of the shoot into nodes, to which dentate leaves are attached. At the base, they grow together, forming a kind of vagina. The cells of the educational tissue are located in the nodes, due to which the intercalary growth of horsetails in height occurs. The underground organ of the horsetail is the rhizome, also divided into internodes. The function of photosynthesis in these plants is performed by a ribbed stem. It contains many cavities filled with water and oxygen.
Horsetail sporophyte is a green shoot that looks like a small young pine. And the gametophyte exists separately and looks like a green plate. One of the most common types of this department - field horsetail - has two types of shoots. The first is also called spring, it is not able to carry out photosynthesis and carries spore-bearing spikelets. Summer, green, - vegetative.
General characteristics of ferns
What is the difference between ferns and horsetails and club mosses? The answer is obvious. This department is the most numerous and diverse, and its modern representatives have a more complex structure compared to horsetails and club mosses. Among the 10,000 species currently growing, there are herbs, shrubs, and trees.
The group of isosporous ferns is represented by aquatic inhabitants - these are Salvinia floating and Marsilia four-leaved. They freely float on the surface of water bodies with a small current. In the tropics, the Azolla aquatic fern is common, which forms a symbiosis with cyanobacteria that can absorb atmospheric nitrogen.
Sporous ferns grow in moist and shady forests. Their typical representatives are the common bracken, the male boletus, the female boletus and other species.
It is about such plants that there is an amazing legend that a fern flower found on the night of Ivan Kupala will be endowed with an amazing gift - it will learn to understand the language of all living beings. However, from a biological point of view, this is impossible. Higher spore plants, including ferns, do not form flowers and fruits.
How a person uses horsetails, club mosses and ferns
Higher spore plants have long occupied their niche in nature and human life. Ferns are part of a large number of plant communities, used to create landscape decoration and as medicinal plants. But the mostthe important role of these plants in nature lies in the formation of a valuable mineral - coal.
In ancient times, all spores were giant trees. Dying away, their trunks, in conditions of lack of oxygen and high pressure of the layers of the earth, turned into coal.
How a person uses horsetails, club mosses and ferns can be easily imagined using medicine as an example. All of them are valuable medicinal plants. For example, horsetail has a hemostatic and diuretic effect. One of the representatives of the lycopsid department - common ram - is used as a means to combat alcoholism.
The spores of these plants have long been used to make fireworks. In the pharmaceutical industry, club mosses are also used to sprinkle pills and make baby powder.
The main value of higher spore plants is still in the formation of coal. This valuable mineral has long been an important source of energy, since its combustion releases a large amount of heat. The electric power industry of many countries is based on this raw material.
Thus, club mosses, horsetails, ferns are a group of higher spore plants, which is widely represented by fossil and ancient species. They are the first land-dwellers, which became possible due to the appearance of more progressive structural features: tissues and organs.
