The most amazing and beautiful part of modern flowering plants is a flower. Different plants have different flowers: some have large and fragrant flowers, others have small and unattractive flowers. But all the flowers on our planet perform the same function - reproduction. For this function in any flowering plant, two organs are responsible, which contains each flower - pistil, stamen. Each plant has its own peculiarities in the location of these reproduction organs.
Flowers grow on shoots. Very evolution has optimized the process of reproductivity, and often the shoot throws off several branches, in each of which a separate flower is formed. This form of flowers is called the inflorescence.
Inflorescences are complex and simple. Simple collections of flowers collect all the flowers on the main axis of the shoot. Inflorescences complex characterized by the fact that on the main axis are not individual flowers, but small branched inflorescences that reflect the structure of the flower. The scheme of a typical inflorescence is given below:
Large flowers usually grow one by one. In the inflorescence, smaller flowers are collected. Collected together, they give inflorescence structural and colorful, saturating the air around yourself with the aroma of nectar. This wonderful smell attracts insects that tend to the flower and in passing the pollen from one flower to another.
In the inflorescence, too, more seeds and fruits are produced than in single flowers. Thus, the probability of a greater spread of a particular plant species on earth is achieved. This is the biological significance of the formation of inflorescences.
Some inflorescences in the process of evolution began to look like one huge single flower. So bloom sunflower, chamomile, cornflower, viburnum, dahlia and many other famous plants. Insects and animals that collect nectar, pay attention to such large and bright flowers. Therefore, pollinating animals can pollinate several inflorescences at once.
The structure of the flower
The flower scheme presented below gives an idea of the typical structure of this organ. Flowers of various plants are located on the peduncle. This is the last nodule on the stem of the plant. The place on which, as on a palm, the flower itself is blossoming, is called the flower-root. This organ is the frame on which the structure of the flower is based. The pedicel is surrounded by the perianth, which protects the pistil and stamen and attracts insects to this flower.
Some perianth form a corolla. This is the name of the set of internal petals of the flower, which have a bright, contrasting color. The corolla serves to visually attract insects that collect pollen.
The scheme of a typical flowering plant is shown below.
2- stamina thread;
All this complex design is provided for the performance of reproductive function. The main organs responsible for the appearance of the fetus are the stamen and pestle. For an example and comparison of these parts of the flower, let's consider how they are arranged in a tulip and cherry.
The structure of the stamen and pestle
Cherry and tulip are absolutely different plants, they can not be confused even by a child. Nevertheless, the stamen and pestle of these representatives of the flora have much in common. Both species belong to the kingdom of angiosperms. Pistil tulip does not have a column, and the stigma sits right on top of the ovary. The stigma is never smooth. Usually it is rough, branched, sometimes even gluey. Such difficulties in the structure of the stigma are due to the fact that he needs to collect as much as possible and leave the pollen for fertilization. Sometimes the stigma is located high on the column - at a higher altitude it is much better to catch the pollen.
The pistil and staminate, the scheme of which is presented below, reflect the typical structure of the reproductive organs of the angiospermous plant.
The ovary is called the expanded, lower part of the pistil. In it there are female ovules of the plant - the ovules. In this part of the pistil, rudiments of future seeds and fruits ripen. Cherry has one ovule, and the tulip has several dozen. Therefore, all the fruits of the cherry are single-seeded, and the tulip simultaneously develops and ripens many seeds.
And in the tulip, and in the cherry, the kinds of stamens are the same. They consist of a thin thread and a large anther. Inside the anther there is a large accumulation of pollen, in which each speck of dust is a separate male germ cell. The cherry blossom has many stamens, and the tulip has only six of them. The transfer of pollen from the anther to the stigma is called pollination. After the pollen has settled on the stigma, fertilization takes place - the male sex cells merge with the female, giving birth to a new fetus.
As can be seen from the description, both the stamen and the pestle are equally important for fertilization. It is in the pestle that the fetus is born, therefore this plant organ is the female part of the flower. Stamens, in turn, are called the male part of the flower.
Male and female flowers
In the examples of cherries and tulips considered above, a stamen and pestle were contained in each flower of this plant. Such representatives of the plant world are called bisexual. But in some plants in flowers there are either stamens or one pistils. Such representatives of our flora are called same-sex. Among the same-sex plants - cucumbers, mulberry, poplar, sea buckthorn. Each individual specimen of the same-sex form has either male or female flowers.
Designation of male and female plants
In botany, pistil (female) flowers are designated as the astrological symbol of Venus. And the male (staminate) marks the sign of Mars.
Monoecious and dioecious
Stamen and pistillate flowers are often located on the same plant. Thus, this tree or bush is capable of self-pollination and reproduction without outside help. Plants, which are inherent in this quality, are called monoecious. Typical monoecious plants are cucumbers, pumpkin, hazel. In other representatives of the plant world, stamens and pistils are found on different plant copies. This feature allowed botanists to distinguish these specimens in the class of dioecious plants. Widespread such dioecious species, as willow, nettle, poplar, aspen.
Urban residents of the central strip of our country is well acquainted with poplar - a typical dioecious plant. In spring poplars scatter pollen, and in early summer, female specimens of this species drop white fluff. Known to all white clouds are parachutes, with the help of which poplar spreads its seeds. Thin lace threads of fluff allow the seed to stay in the air and fly away from the parent tree for a considerable distance. The same method of spreading their own fetuses is inherent in dandelions.
Stamens and pistils are the most important components of any flowering plant. Understanding the principles of plant propagation in nature is important in many areas of our daily life. For example, the above described method of breeding poplars leads to numerous allergic diseases. Planting only the male individuals of this plant can reduce the number of sick leaves in urban enterprises and improve the health of the inhabitants of this locality.