请输入您要查询的英文单词:

 

单词 pollen tube
释义

pollen tube

noun Botany
A hollow tube which develops from a pollen grain when deposited on the stigma of a flower. It penetrates the style and conveys the male gametes to the ovule.Guidance of the pollen tube down the style involves mechanical, chemical and physical cues that are not yet fully understood....
  • In pre-zygotic mechanisms, the pollen tube may grow as far as the ovule but not penetrate it, or penetration may be achieved without fertilization.
  • The grain is empty because the body cell and prothallial nuclei have moved out along the pollen tube towards the archegonia.
随便看

 

英语词典包含243303条英英释义在线翻译词条,基本涵盖了全部常用单词的英英翻译及用法,是英语学习的有利工具。

 

Copyright © 2004-2022 Newdu.com All Rights Reserved
更新时间:2025/2/23 23:58:17