What are the conditions required for pollen germination to grow pollen tubes

Mature pollen grains are transmitted to the stigma and, after mutual recognition, rejects the more distant alien and xenogeneous pollen grains and accepts the same pollen grains, or rejects their own (homogeneous or homogeneous) pollen grains and accepts the same genotype of pollen grains. After the pollen grains with affinity accepted by the stigma absorb water and expand, the inner wall protrudes outward through the germination hole on the outer wall, forming a pollen tube and germinating. It takes a certain amount of time from pollen grains to stigma to germination.

The length of this period varies from plant to plant. For example, rice, sugarcane, sorghum, etc., germinate almost immediately after pollination; Corn, rubber grass, etc. take about 5 minutes; Cotton takes 1 to 4 hours.

The enzymes and various metabolites stored in pollen grains are important factors for pollen germination. For example, the cutinase enzymes present in pollen grains and pollen tubes degrade the cuticle present on the surface of most plant stigmas, allowing pollen grains to absorb the water necessary for germination from stigma tissues and opening channels for the growth of pollen tubes. Metabolites stored in pollen grains.

It provides a material basis for the initial growth of pollen tubes. In addition, the secretions on the surface of the wet stigma provide an essential substrate for pollen germination, especially the changes in phenolic substances in it, which can promote or inhibit pollen germination. Although there is no exudation overflow from the dry stigma, the hydrophilic protein film on its surface has the effect of assisting in adhesion of pollen or hydrating pollen, so that pollen can obtain the necessary water for germination.

In the stigma and columella tissue, the ubiquitous boron has the ability to increase oxygen absorption and promote the absorption and metabolism of sugar, which is conducive to the synthesis of pectin, thus promoting the germination of pollen and the growth of pollen tubes.

1.The vegetative cells in mature pollen store a large amount of starch, fat, protein, various enzymes, vitamins, plant hormone pigments, and inorganic salts, which are the material conditions for pollen germination and pollen tube growth.

2.The stigma is where the pollen tubes germinate.

There is a hydrophilic protein film on the surface of the mastoid cells, which has the effect of binding pollen and hydrating pollen to provide conditions for pollen germination.

At the same time, the stigma has the function of recognizing pollen, only the wall protein on its surface and the protein recognition reaction of the stigma surface membrane through the pollen, that is, the affinity pollen grain, can immediately absorb water from the stigma, restore the enzyme activity and start various physiological functions, under the action of the enzyme, the inner wall of the pollen protrudes from the germination hole outward, and the pollen tube germinates.

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a certain temperature, sucrose and boric acid.

After pollination is completed, the pollen begins to germinate and grow pollen tubes under the action of mucus on the stigma, so the pollen germinates and grows the stigma of the pistil

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