A new interpretation of the structure of the megaspore membrane in some gymnospermous ovules
A new interpretation of the structure of the megaspore membrane in some gymnospermous ovules
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对某些裸子植物胚珠大孢子膜结构的新解释
DOI：
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发表时间：
1966
期刊：
影响因子：
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通讯作者：
J. Pettitt
中科院分区：
文献类型：
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作者：
J. Pettitt
摘要
对裸子植物胚珠个体发育过程中绒毡层的光镜和电子显微镜观察表明，最终绒毡层退化并在胚囊和珠心之间形成一层厚厚的抗乙酰水解膜(绒被膜)。这个膜不被认为是大孢子膜的一部分，因为这个术语用于自由孢子形成的异源孢子植物。
在所研究的属的成熟胚珠中，真正的大孢子膜是一种薄的、不发生乙酰分解的膜，与周围的原叶细胞密切相关，位于较厚的绒毛膜内部。这种大孢子膜可能与发育早期存在的更精细的结构有关。
有强有力的证据表明，胚珠绒毡层中的事件在某种程度上与花粉囊的绒毡层中的事件平行。
SUMMARY
A light and electron microscope investigation of the tapetum during stages in the ontogeny of a variety of gymnospermous ovules reveals that eventually this tissue degenerates and forms a thick acetolysis-resistant membrane (the tapetal membrane) between the embryo sac and the nucellus. This membrane is not considered part of the megaspore membrane in the sense that that term is used in free-sporing heterosporous plants.
In the mature ovules of the genera investigated the true megaspore membrane is present as a thin, acetolysis-proof membrane closely associated with the peripheral prothallial cells and internal to the thicker tapetal membrane. This megaspore membrane can be related to a somewhat more elaborate structure that is present at the earlier stages of development.
There is strong evidence to suggest that the events in the tapetum of the ovule are to some extent paralleled in the tapetum of the pollen sac.