The most amazing and beautiful part of modern flowering plants is a flower. Different plants have different flowers: in some they are large and fragrant, in others - small and inconspicuous. But all the flowers on our planet perform the same function - reproduction. For this function in any flowering plant are responsible two organs that each flower contains - a pistil, stamen. Each plant has its own characteristics of the location of these organs of reproduction.
Flowers grow on shoots. Very evolution has optimized the process of reproduction, and often the shoot throws away several branches, in each of which a separate flower is formed. This form of flower formation is called inflorescence.
Inflorescences are complex and simple. Simple sets of flowers collect all the flowers on the main axis of the shoot. The inflorescences are complex, characterized by the fact that the main axis does not have separate flowers, but small branched inflorescences that reflect the structure of the flower. A typical inflorescence pattern is shown below:
Large flowers usually grow alone. In the inflorescences are going smaller flowers. Taken together, they give the inflorescence structural and colorful, saturating the air around them with the scent of nectar. This wonderful smell attracts insects that tend to flower and in passing carry pollen from one flower to another.
In the inflorescence also produces more seeds and fruits than in single flowers. This achieves the likelihood of greater spread of a particular plant species on earth. This is the biological significance of the formation of inflorescences.
Some inflorescences in the process of evolution began to look like a single 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, animal pollinators can pollinate several inflorescences at once.
The scheme of the flower presented below gives an idea of the typical structure of this organ. The flowers of various plants are located on the stem. This is the name of the last nodule on the stem of the plant. The place where, like on a palm, the flower itself blooms, is called a receptacle. This body is the framework on which the structure of the flower is based. A perianth that surrounds the pistil and stamen and attracts insects to this flower.
Some perianths form a corolla. This is the name of the combination of the inner petals of a flower, which have a bright, contrasting color. The corolla serves to visually attract insects that collect pollen.
A schematic of a typical flowering plant is presented below.
2 - tychinochnaya thread;
All this complex construction is provided to perform the reproductive function. The main organs responsible for the emergence of the fetus are stamen and pistil. For an example and comparison of these parts of a flower, let’s look at how they are arranged for a tulip and a cherry.
The structure of the stamen and pistil
Cherry and tulip are completely different plants; even a child will not confuse them. However, the stamen and pistil of these representatives of the flora have much in common. Both species belong to the kingdom of angiosperms. The pestle of the tulip has no column, and the stigma sits directly on the top of the ovary. The stigma is never smooth. Usually it is rough, branchy, sometimes even sticky. Such difficulties in the structure of the stigma 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 a column - at a higher height it is much better to catch pollen.
The pistil and stamen, the diagram of which is presented below, reflect the typical structure of the reproductive organs of an angiosperm plant.
The ovary is called the dilated, lower part of the pistil. In it are the female ovules of the plant - ovules. In this part of the pistil, the beginnings of future seeds and fruits ripen. Cherry has one ovule, and the tulip has several dozen. Therefore, all fruits of a cherry are single-seed, while a tulip develops and ripens many seeds at the same time.
Both tulip and cherry have the same types of stamens. 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 plant pollen from the anthers on the stigma is called pollination. After the pollen has settled on the stigma, fertilization occurs - the male sex cells merge with the female, giving birth to a new fetus.
As can be seen from the description, both stamen and pistil are equally important for fertilization. It is in the pistil that the fetus is born, therefore this plant organ is the female part of the flower. The stamens, in turn, are called the male part of the flower.
Male and female flowers
In the above examples of cherries and tulips, the stamen and pistil were contained in each flower of this plant. Such representatives of the flora are called obsepolymi. But some plants in the flowers are either stamens, or some pistils. Such representatives of our flora are called same-sex. Among same-sex plants - cucumbers, mulberries, poplars, sea buckthorn. Each individual instance of the same-sex species has either male or female flowers.
Designation of male and female plants
In botany, pistillate (feminine) flowers are used to designate the astrological symbol of Venus. A male (staminate) mark the sign of Mars.
Monoecious and dioecious
Staminate and pistillate flowers are often located on the same plant. Thus, a given tree or shrub is capable of self-pollination and reproduction without assistance. Plants that have this quality are called monoecious. Typical monoecious plants - cucumbers, pumpkin, hazel. Other members of the plant world have stamens and pistils on different plant specimens. This feature allowed botanists to allocate these specimens to the class of dioecious plants. Such dioecious species as willow, nettle, poplar, aspen are widespread.
The urban residents of the middle zone of our country are familiar with the poplar - a typical dioecious plant. In the spring of poplar, pollen is scattered, and in early summer, female specimens of this species drop white down. The white clouds known to all are parachutes with which the poplar spreads its seeds. Thin lace threads of fluff allow the seed to better stay in the air and fly away from the parent tree for a considerable distance. The same method of distribution of their own fruits 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 method of breeding poplars described above leads to numerous allergic diseases. Planting only males of this plant can significantly reduce the number of sick-lists in urban enterprises and improve the health of the inhabitants of this locality.