Early events occurring at the surface of the female organ are critical for plant reproduction, especially in species with a dry stigma. After landing on the stigmatic papilla cells, the pollen hydrates and germinates a tube, which penetrates the cell wall and grows towards the ovules to convey the male gametes to the embryo sac. In self-incompatible species within the Brassicaceae, these processes are blocked when the stigma encounters an incompatible pollen. Based on the generation of self-incompatible Arabidopsis lines and by setting up a live imaging system, we showed that control of pollen hydration has a central role in pollen selectivity. The faster the pollen pumps water from the papilla during an initial period of 10 min, the faster it germinates. Furthermore, we found that the self-incompatibility barriers act to block the proper hydration of incompatible pollen and, when hydration is promoted by high humidity, an additional control prevents pollen tube penetration into the stigmatic wall. In papilla cells, actin bundles focalize at the contact site with the compatible pollen but not with the incompatible pollen, raising the possibility that stigmatic cells react to the mechanical pressure applied by the invading growing tube.

中文翻译：

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自交不亲和拟南芥花粉感知后早期事件的活细胞成像。


雌性器官表面发生的早期事件对于植物繁殖至关重要，特别是对于柱头干燥的物种。落在柱头乳头细胞上后，花粉水合并萌发一根管子，该管子穿透细胞壁并向胚珠生长，将雄配子输送到胚囊。在十字花科的自交不亲和物种中，当柱头遇到不亲和的花粉时，这些过程就会被阻止。基于自交不亲和拟南芥品系的产生并通过建立实时成像系统，我们表明花粉水合的控制在花粉选择性中起着核心作用。在最初的 10 分钟内，花粉从乳头中吸水的速度越快，发芽的速度就越快。此外，我们发现自交不亲和屏障会阻碍不相容花粉的适当水合作用，并且当高湿度促进水合作用时，额外的控制可防止花粉管渗透到柱头壁中。在乳头细胞中，肌动蛋白束集中在与相容花粉的接触部位，但不与不相容花粉接触，这增加了柱头细胞对入侵生长管施加的机械压力做出反应的可能性。