Ferns appeared on Earth many years ago. In ancient times it was possible to meet forests of tree ferns. To date, such large plants are very few. Ferns have become more decorative and indoor. They are beautiful and unpretentious, they can be used for landscape design. Plants are durable and interesting.
Fern Legends
Fern is an unusual plant. A great many beautiful legends are associated with his appearance. According to one of them, the plant came from the goddess of love - Venus, who once dropped her hair, from which the fern grew.
The most famous legend is the legend of fern bloom. It says that if you see a flower of a plant on the night of Ivan Kupala , the secret will open before a person how to find treasures. However, when studying it, it becomes clear that the legend cannot be embodied in reality, since the life cycle of a fern does not have a flowering stage.
Higher and lower plant groups
Plants are divided into higher and lower groups. They differ in their environment. Higher plants "came out" on land and spend their life cycle on earth. These plants include ferns. Earthly plants have a clear division into the root, stem and leaf.
However, it cannot be said unequivocally that ferns have completely moved away from the aquatic environment, since a free-living gametophyte is involved in their reproduction and sperm cells necessary for the fertilization process can exist only in the aquatic environment.
Appearance
Representatives of the fern detachment spread throughout the world. They have a different appearance of leaves, environmentally unpretentious, while more like moist soils.
Fern has a root system, stem and leaves. He has no seeds. On the inner side of the sheet, below, spores are located in sporangia sacs. The leaves of the fern are called "vayi", they are not like the leaves of other plants. They look as if several branches were laid in one plane and attached to the stem. Their color may vary from light green to dark green.
The fern, apart from the root system, consists of vayya, sorus and hinduia, where the sorus is a bunch of sporangia, and the industry is a sprout that resembles an umbrella that closes the sorus.
Life cycle of higher plants
Existing on Earth, each plant goes its own way. The life cycle of a fern is a movement from the origin of life to the full maturation of a plant that can give a new life. The cycle consists of two phases: asexual and sexual. These phases determine the sequence of generations, one occurs with the help of gametes - sexual, the second - with the help of spores - asexual.
When merged, gametes form a diploid zygote, which gives rise to a new generation, asexual. In the asexual generation, reproduction occurs through spores. Haploid spores give rise to sexual generation. One generation always prevails over the other and makes up most of the plant's life cycle.
Fern Life Cycle Stages
For the emergence of a new young sprout, several stages are necessary. The life cycle of a fern is the totality of all phases, from the birth of life to the phase of maturity, when the plant is already capable of giving rise to a new life. The cycle is closed.
The stages of the life cycle of ferns are arranged in the following sequence:
- Spore.
- Gametophyte (seedling).
- Ovum, sperm.
- Zygote.
- The embryo.
- Young plant.
When all the stages have been completed, the young plant, having developed and strengthened, will be able to repeat this cycle for the birth of the next generation.
Asexual and sexual stages in the process of reproduction
Fern is the result of an asexual generation. Consider the sequence of the fern life cycle.
In order to start a new life, in an adult plant, spore sacs should appear on the back of the leaf, in which spore maturation will take place. When the spores are ripe, the pouch will burst and spores will fall out of it. Under the influence of wind, they will spread in different directions and will sprout if they reach a favorable soil. This stage is very important, because without it the plant could not exist. As a result, a process will appear - a gametophyte - the sexual generation of fern. In its form, it looks like a heart. This heart has thin strings below - rhizoids, with which it is attached to the soil. The fern growth is bisexual; small sacs are located on it: in some, the eggs mature, in others, the sperm. Fertilization occurs with the help of water.
Since the seedlings are very small and have such a peculiar shape, this contributes to the slow runoff of rainwater and its retention below. Due to this, sperm can swim to the eggs and fertilize them. As a result, a new cell appears - the zygote, from which the sporophyte embryo is formed - the result of a new asexual generation. This embryo consists of a haustorium, which in its appearance resembles a stem growing into a seedling, and at first it consumes from it the substances necessary for its growth. After a while, the first leaf of the embryo appears, which serves as the beginning of the development of fern.
Thus, the asexual generation prevails in the life cycle of fern, which gives birth to a new large and long-lived plant, and the sexual generation is small and quickly dying. Moreover, it is necessary for fertilization.
Fern propagation at home
Ferns are interesting and original plants. Therefore, they are often bred at home. In order for the fern life cycle to go through completely and a new young plant is obtained, it is necessary to germinate the spore. A leaf of an adult fern, on which bags with spores appeared - brown tubercles, is cut off and placed in a paper bag. This bag is kept for one day in a warm place, shaking occasionally.
While the spores mature and fall out, prepare a mixture for planting. They take a steamed mixture of peat, greens, sand, crushed charcoal is also added there, all this is taken in equal proportions. The prepared mixture is laid out in shallow pots, pressed and moisturized.
Ripened and precipitated spores are removed from the bag and poured onto the prepared surface. For their germination create favorable conditions:
- Temperature: optimally 25 degrees Celsius.
- Maintain high humidity.
- Cover the pots with glass.
Water the pots from the spray gun. When a sprout appears, watering is given special attention, since the subsequent development of the plant is possible only in the presence of an aqueous medium in which the egg is fertilized.
As soon as the first leaves appear, remove the glass. Then they are given some time to adapt to the environment and dive into ditches. When the leaves begin to grow a little, they are first kept in cold greenhouses, and then planted in separate pots. Thus, new young plants are obtained, ready to grow and develop further.
Life Cycle Schematically
When propagating, the plant goes through several stages. For clarity and better memorization, a schematic accompaniment of this issue is recommended. Consider the existing fern life cycle, the scheme of which is presented below:
1. An adult plant that can give a new life.
2. Spores appear on fern leaves.
3. Bags with spores mature.
4. The bag bursts, spores fall out.
5. In favorable soil, the spore strengthens and sprouts.
6. A seedling forms, which is attached to the ground with the help of rhizoid filaments.
7. At the embryo there are female and male cells: archegonia and anteridia:
- Female genitals contain an egg.
- Male genitals contain sperm.
- Fertilization is possible only in a drop of rain.
- Sperm swim to the eggs and penetrate, fertilization occurs.
8. A fertilized egg, a zygote, appears. A sporophyte is formed from a zygote - a young leaf.
9. A new young plant begins to develop.
The diagram clearly shows the isolation of the life cycle.
Economic value
The role of fern-shaped in human life is not too great. Various forms of nephrolepis are common indoor ornamental plants. The waiyi of some scaravatus are widely used as a green component of floral arrangements. Trunks of tree ferns serve as building material in the tropics, and in Hawaii their starchy core is eaten.
Conclusion
So, we studied the life cycle of this plant. You have learned, for example, at what stage in the life cycle of ferns an embryo appears. These are hygrophilous plants; without water, their reproduction is impossible. They spread throughout the world, while for their life they choose places with high humidity.
In total there are about 10 thousand varieties of ferns. They are medicinal, decorative, indoor.
When a new young plant is born, a life cycle begins, which includes sexual and asexual generations. The sexual generation is a seedling, it is very small and does not live long, and the newly emerged young strong long-lived plant is an asexual generation. In the life cycle of fern, the sporophyte phase predominates.
Thus, the main generation of fern is asexual, while reproducing, bypassing the sexual generation, is impossible.