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怎么说呢，这个系列就是把自己的homework拿出来晒一晒，也就是图一乐丢人现眼一下，因为本人能力和知识范围有限，难免会有错误，请谅解一下，也就是仅供参考。引文都有标注，如果有侵权的可以联系我。欢迎各位大佬多交流，提问题、指错误。要是能关注一波那就更好了！ 

The Processes Of Pollination And Double Fertilization In Arabidopsis

1 Pollination

Pollination in angiosperms is the process of transferring pollen grains from the anther of the stamen, the male organ of the flower, to the stigma of the pistil, the female organ of the flower.

Arabidopsis thaliana (L.) Heynh.is Angiospermae phyla,Dicotyledoneae, Cruciferae.Annual herbs,Usually self-pollinated, flowering pollinated, in rare cases rely on insect or wind cross-pollinated.

2 Fertilization

Fertilization in Arabidopsis is the process of both sexual gametes fuse with each other within the flowers,this process has been divided into three phases.

2.1 Pollen grain germinates

   After pollen grain landing on the stigma, lipids and proteins from the pollen coat flow out onto the stigma and mingle with materials from papillar cells to form the “foot,” a structure that attaches the pollen grain firmly to the tip of the papillar cell. During this process, the lipids in the foot are thought to reorganize, creating a capillary system through which water and ions can flow from the stigma to the pollen grain.After hydration, the volume and metabolism of the pollen grain increases, the internal material of the vegetative cells increases, and the intracellular pressure increases, forcing the intine wall of the pollen grain to highlight toward the germ pore, forming a pollen tube.

2.2 Pollen tubes grow

  Following germination, the pollen tube begins to grow though the nutrient-rich extracellular matrix of the transmitting tissue that connects the stigma, style, and ovary.Then,the pollen tube reaches the embryo sac through the micropyle after crossing the septum to the ovary.Finally, Pollen tube penetrates the egg sac, and enters one of the synergid cells through the filiform apparatus. Pollen tube ceases to grow, and the tip bursts to release the two sperm cells.

2.3 Fertilization

  The fertilization can be divided into three stages in Arabidopsis. First, the pollen tube bursts within a few seconds of entering the synergid,the sperm and contents were injected into the embryo sac. Second, the two sperm cells remain stationary at a boundary region between the egg cell and the central cell for approximately 7 min. Third, one sperm fuse with egg cells to form a zygote,it will develop into embryos in the future.the other fuses with the central cell to form primary endosperm cell,it will develop into endosperm in the future,completing double fertilization.

Reference：

[1] 谭永耀,拟南芥自然居群的传粉机制与交配系统,【D】,武汉大学,2004,undefined

[2] Lincoln Taiz, Eduardo Zeiger, Ian M. Møller, and Angus Murphy Plant Physiology and Development, Sixth Edition [M] published by Sinauer Associates.2015

[3] 马炜良主编，马炜良、王幼芳、李宏庆 编著. 植物学 第2版[M]. 北京：高等教育出版社, 2015.08