Pollen grain germination

the pollen particles transmitted to the head of the female column through pollination, and the process of creating pollen tubes through the germination holes, in interaction with the column head. Mature pollen grains are transmitted to the column head, after mutual identification, repelling distant heterogeneity and heterogeneity pollen grains, accepting the same pollen grains, or repelling their own (same strain or the same flower) pollen grains, accepting the same different
gene
type of pollen particles. The affinity pollen grain accepted by the column head, after absorbing water expansion, the inner wall protrudes outward through the germination hole on the outer wall, forming a pollen tube, which can germinate. It takes a certain amount of time to pass from pollen grains to the head of the column to germination. The length of this time varies from plant to plant. For example, rice, sugar cane, sorghum, etc., sprouted almost immediately after pollination;enzymes stored in pollen grains and various metabolic substances are important factors in pollen germination. For example, the presence of cuticle enzymes in pollen grains and pollen tubes degrades the cuticle layers present on the surface of most plant column heads, allowing pollen grains to absorb the moisture necessary for germination from the column head
or tissue
and opening the way for pollen tubes to grow. A metabolic substance stored in pollen grains. It provides a material basis for the initial growth of pollen tubes. In addition, the secretion on the surface of the wet column head provides the necessary substation for pollen germination, especially the change of phenolic substances, which can promote or inhibit the germination of pollen. Although there is no secretion spillage of the dry column head, but its surface hydro-hydro-friendly
protein
film, there is auxiliary adhesive pollen or hydration pollen, so that pollen to obtain the necessary moisture for germination. In the column head and flower column tissue, the common boron, which increases the absorption of oxygen and promotes the absorption and metabolism of sugar, is good for the synthesis of cysts, and thus promotes the germination of pollen and the growth of pollen tubes.flower grain in artificial
culture
base or column head germination, in a certain area, the number of pollen grains, its germination rate is high, pollen tube growth is also good, for example, apple pollen,
per milliliter When the
contains 40×10
3
grains, the germination rate is 13%, and when it contains 280×10
3
grains, the germination rate jumps to 74%. This phenomenon is called the collective effect of pollen and is related to pollen growth factors, a substance secreted by pollen particles themselves that is effective for pollen germination.