Pollen-tube growth and fertilization mode in Gymnostoma (Casuarinaceae): their characteristics and evolution
Pollen-tube growth and fertilization mode in Gymnostoma (Casuarinaceae): their characteristics and evolution
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DOI：
10.1007/s10265-004-0148-4
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发表时间：
2004-03
影响因子：
2.8
通讯作者：
A. Sogo;T. Jaffré;H. Tobe
中科院分区：
文献类型：
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作者：
A. Sogo;T. Jaffré;H. Tobe
在木麻黄科衍生属的几个物种中，已知一种独特的受精模式称为“合偶制”，即花粉管通过合偶带而不是微孔。在本文中，我们报告了异构体间膜瘤(G。泊松属)，科中最原始的属。我们还发现花粉管在大约3个月的时间里从柱头不连续地生长到胚珠。授粉时，胚珠尚未在子房内形成，需要很长时间才能发育。花粉管呈锯齿状，在花柱的上部有分支，它们的生长在那里被阻止，直到子房进一步发育。对相关文献的研究进一步揭示了与木麻黄科密切相关的桦木科、核桃科和壳斗科的花粉管生长不连续与授粉和受精之间的间隔时间较长有关，并发现了配子交配现象。这一特征可能在Fagales进化的早期就产生了。
A unique mode of fertilization called “chalazogamy”, whereby the pollen tube passes through the chalaza instead of the micropyle, is known in several species of derived genera in Casuarinaceae. In this paper we report the occurrence of chalazogamy inGymnostoma(G. poissonianum), the most primitive genus in the family. We also show that the pollen tube grows discontinuously from the stigma to ovules in about 3 months. At the time of pollination, the ovules have not yet formed in the ovary, and require a long time to develop. The pollen tube(s) lie in a zigzag line and are branched in the upper region of the style, and their growth is arrested there until the ovary develops further. Studies of the relevant literature further revealed discontinuous pollen-tube growth in relation to a prolonged period between pollination and fertilization, as well as chalazogamy, in Betulaceae, Juglandaceae and/or Fagaceae that are closely related to Casuarinaceae. This feature may have derived early in the evolution of Fagales.