Learn why in flowering plants called double fertilization

Theme: “Why in flowering plants called double fertilization" studying in the sixth grade. However, not every person will be able to explain the details of this process.

Plants, like all living creatures, breed, using three main ways. The first is vegetative, that is, a new plant appears from any part of his “parent” - root, stem, leaf, even a single cell. The second one is called asexual because the plants emerge from spores and is similar to the parent. Multiply fungi and some algae. The most perfect is the fertilization of plants in the sexual way.

In the vegetable world this process occurs by fusion of gametes, which may be the same size (izogamiej), different size (heterogamy) and fundamentally different from each other (oogamy). We can say that fertilization is the process of Union of the male (sperm) and female (egg) gametes, resulting in the formation of a cell with a doubled set of chromosomes (zygote) from which a new plant.

Why in flowering plants called double fertilization? Here there is a special reproductive organs-flower. Its constituent parts are the stamens on filaments with an anther (contains the pollen), ovary, style, pistil (with stigma), the pollen tube reaches the embryo SAC, where the ovule. From school biology course, many people remember something about the pistil and stamen and may think: that's why in flowering plants called double fertilization. But it is not.

In the boot, as already stated, the pollen is formed, which consists of two cells-big vegetative and a smaller generative. When a boot is disclosed, these elements are distributed by the wind or insects. Hitting the pestle (directly on the stigma), the pollen cells germinate so that the vegetative part is getting the pollen tube, attached to the embryonic sack. Through it in the bag gets a generative cell, which in the course of its penetration is divided into two sperm cells. One of them reaches the egg, fuses with it, forming a zygote, and the second is connected with the secondary core. This process is the reason why in flowering plants called double fertilization.

Some modern plants successfully combine different methods of reproduction increases the survival of the species. And at a time when this process was in its infancy, this method of reproduction was very important evolutionary process. This is due to the fact that the body created through the merger of cells with different chromosome sets possessed a greater variability and adaptability to the environment. Modern physico-chemical studies have shown how sexual reproduction of plants are intrinsically complex. For example, it was found that the pollen and stigma of the pistil have different pH levels, excellent levels of isoelectric point of proteins, different enzyme and amino acid composition, which, however, optimizes the physiological processes while connecting these cells.