Gymnosperms are the basis of the flora of certain regions of the Earth. They are the lungs of our planet, supplying huge volumes of oxygen and reducing the concentration of carbon dioxide. The nutritional value of gymnosperms is the supply of food to birds and rodents.
General characteristics of seed
The first plants propagating by seeds appeared in the middle of the Devonian period. However, their superiority over the disputed appeared at a later time. Scientists attribute this event to climate change: a decrease in temperature and precipitation in the Mesozoic era. The variety and importance of gymnosperms and flowering plants have significant differences. Both of these departments of higher flora are similar in the presence of roots, shoots and generative organs.
Plants propagating by seeds have some superiority over spore ones. The main distinguishing features:
- A spore consists of a single cell, and a seed consists of many.
- Pollination is the process of transferring pollen grains to seed buds. Sometimes wind, insects or animals are required for this purpose.
- The seed consists of a germ, the required amount of nutrients and a shell that protects against external influences.
- There is no need for water for fertilization.
General characteristic of gymnosperms
The known importance of gymnosperms in nature is due to their structure. There are about 700 modern species of these plants. Their seed is on top of the flakes openly. All their protection is the peel. It was possible to reduce evaporation from the surface with the help of stomata that appeared.
Conifers have a height of 40 to 70 m, however, there are species that reach 100 m, including the mammoth tree. An increase in stem thickness is provided by cambium cells, which die off over time. This provides reliable protection against strong winds. The bark of coniferous trees has many tubules with resin, which flows through the damaged areas, healing them. Another meaning of gymnosperms in nature is the accumulation of carbon, which will then turn into deposits.
Gymnosperms
To better understand the importance of gymnosperms, it is worth considering their reproduction. We will do this using the example of a pine tree, the seeds of which appear when the tree reaches the age of 12 to 15 years. Cones are organs in which seed buds and pollen grains mature. They were formed as a result of a modification of the shoots, which became shorter, and the leaves turned into scales.
Pine refers to monoecious plants that have reproductive organs of both sexes. Female cones have a reddish tint and tight-fitting scales. Grow in the apex of the shoot. Each flake has 2 seminal primordia. Male cones form at the base of elongated shoots. Their color is yellow gray. Scales have 2 anthers each; pollen forms in them. Its grains have 2 shells, between which there are cavities filled with air. This feature allows pollen to move with the wind far from the place of growth.
Studying the importance of gymnosperms, one cannot miss the process of pollination:
- In spring, pollen with the wind falls on the ovules.
- The cone scales begin to close, completely covering the organ.
- A pollen tube sprouts from pollen grains.
- Fertilization will happen only after a year, when the eggs and endosperm (tissue with a supply of nutrients) appear inside the seed germ.
- A pollen tube is suitable for the egg, along which two sperm move (without flagella). One of them reaches the goal and fertilization occurs, and the second dies.
- Seed is formed from the seed germ.
Seeds
Seeds consist of a peel (formed from the membrane of an embryo), endosperm and embryo. They mature 3 years after the buds grow. The same tree contains them at different stages of development. Pine seed resembles a flower, but has an endosperm, which is formed from a seedling. It is quite resistant to the effects of harsh environmental conditions. It can sprout on rocky ledges and withstand severe frosts. These and many other details determine the importance of gymnosperms.
Ecology gymnosperms
What is the significance of gymnosperms can be imagined by learning how ancient they are. In the Paleozoic and Mesozoic eras, they dominated among the representatives of the flora. These were evergreen trees. Species common in the tropical zone have large dissected leaves (like palm trees). The green organs of plants in the northern latitudes are small (like needles or scales). This is due to low air humidity.
What biological significance does gymnosperms form whole forests? The taiga of temperate latitudes is the native home for many populations of living organisms. This is especially true for birds and mammals (carnivores, omnivores and herbivores). Forests provide them with food, protection, shelters, and breeding and rearing conditions for their young.
Minerals of Siberia are ancient gymnosperms of huge size. Now coniferous forest areas are rapidly declining for various reasons: deforestation, fires, clearing places for roads, cities and factories. Activities related to flooding of territories, drainage of swamps and mining are destructive for taiga.
The most important gymnosperms are the enrichment of air with oxygen and its purification from carbon dioxide. A person is very careless about this function of them, because the increased content of harmful impurities and soot in the atmosphere leads to clogging of stomata and the accumulation of substances in the leaf blade. Needles do not fall annually, so their lifespan is reduced due to this by several years. Deforestation is one of the biggest problems on the planet.
The importance of gymnosperms in human life
The economic use of conifers began long ago. In today's world, it is difficult to imagine many industries and everyday life without them. The use and importance of gymnosperms in different areas of life:
- Food. The corresponding croup is produced from the core of the cycad. The seeds of Siberian cedar are eaten .
- Construction. Wood is an excellent material for finishing and manufacturing structures.
- Fuel Dry wood is used for heating individual houses.
- The medicine. Essential oils, pine buds - the basis for medicines.
- Chemical. From gymnosperms produce turpentine, tar, var, essential oils.
- Aesthetic. Among coniferous trees there are decorative species. Great value gymnosperms in the creation of forest belts along fields and roads.
Next, we consider in more detail the importance of gymnosperms in human life. A report of each gender will be brief.
Pine and spruce
Pine is a typical representative of the temperate flora and subtropical mountains. It grows fast and loves light. Forms burs on sandy soils or mixed forests. Life expectancy up to 400 years. Pine wood is used in the manufacture of aircraft, railway cars, water transport, furniture. Rosin, turpentine and ship resin are produced from resin. Fresh shoots are the raw materials for the manufacture of medicines due to the high content of vitamin C. Medicine uses pollen grains as an alternative to the spores of the cows. Pine is a typical representative of conifers, therefore, the value of gymnosperms is often considered on its example.
Spruce grows in Europe, Western Siberia in the Carpathians. Life expectancy up to 300 years. There are clean spruce trees and mixed with other coniferous and deciduous species. Wood is an excellent building material, fuel. From it, cellulose is obtained - raw materials for paper production. The bark is rich in tannins. Turpentine, rosin, var, resin are made.
Fir and larch
The range of fir is quite wide. This tree tolerates shade and cold. Branches growing close to the ground easily give root. Can be found on the plain and mountainous terrain. Wood is an excellent material for construction, crafts, paper and cardboard. Essential oil is made from pine needles. Camphor and balms are made from young shoots. There are decorative views used in landscape design.
Larch is a typical plant of Eurasia and the North American continent. By winter, her needles fall off, which is not found in other gymnosperms. It is resistant to frost, but loves sunlight. It has a reddish wood that is resistant to dampness. It makes sleepers, supports in mines, paper products. She found application in the manufacture of ships.
Cedar and yew
Cedar grows in the Mediterranean Sea, the Western part of the Himalayas, Siberia. It has a wide crown and great height. Its strong wood is used to create ships.
Yew is a widespread species. There are no pure yew forests. It is typical of mountainous and warm places. Only this representative of conifers has no tar. Wood color is yellow-red. It is widely used as raw material for turning, carpentry and construction work. Furniture is made from it, houses are built. The value of wood is in its resistance to putrefactive processes.
Cypress and juniper
Cypress grows in the temperate climate of Eurasia and North America. It is found in gardens in the Crimea and the Caucasus. The crown has the shape of a pyramid or spreading. Soft and light ornamental material. Furniture is also made of wood.
Juniper grows in all climatic zones of the northern hemisphere. In its pure form forms a bright forest. It is represented by low trees and bushes. Widespread material for crafts and construction. Sanibol is a poisonous essential oil found in shoots. It is used for medical purposes.