Commonalties between pollen/stigma and host/pathogen interactions:: calcium accumulation during stigmatic penetration by Brassica oleracea pollen tubes
Commonalties between pollen/stigma and host/pathogen interactions:: calcium accumulation during stigmatic penetration by Brassica oleracea pollen tubes
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DOI：
10.1007/s004970050192
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发表时间：
1999-09-01
影响因子：
--
通讯作者：
Dickinson, HG
中科院分区：
文献类型：
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作者：
Elleman, CJ;Dickinson, HG
相似之处已经探讨了花粉管柱头渗透和真菌病原体感染表皮细胞的早期阶段。在一个惊人的相似的事件后，Hordeum .感染的Erysiphe graminis， x射线微量分析揭示了钙的积累在柱头表面在甘蓝授粉后。x射线成像强烈显示钙定位在花粉粒或花粉管与柱头乳头表面接触的点上。对这些部位的钙浓度没有明确的测量，但对照表明，钙浓度远远超过了细胞质中发现的水平。花粉/柱头界面的x射线微分析未能检测到硅的存在，硅是表皮细胞在应对病原挑战时经常积累的一种元素。苯丙素生物合成途径在真菌病原体感染后被许多植物宿主激活，并且与自花粉接触24 h后柱头中自荧光物质的积累强烈表明该途径在授粉后也被激活。然而，这种反应的时间表明，酚类产物不太可能参与对自花粉的排斥。从被子植物表皮细胞防御系统的当前观点，以及为什么这些机制不能识别和排斥不相容的花粉管的角度讨论了这些数据。
Parallels have been explored between the early stages of stigmatic penetration by pollen tubes and the infection of epidermal cells by fungal pathogens. In a striking resemblence to events following the infection of Hordeum sp. by Erysiphe graminis, X-ray microanalysis has revealed the accumulation of calcium at the stigmatic surface following pollinations in Brassica oleracea. Xray mapping strongly indicates the calcium to be localised at the points at which either the pollen grain or its tube makes contact with the surface of the stigmatic papilla. No definitive measures were: made of the concentration of calcium at these sites, but controls indicated the levels to be well in excess of those found in the cytosol. X-ray microanalysis at the pollen/stigma interface failed to detect the presence of silicon, an element frequently accumulated by epidermal cells in response to pathogenic challenge.The phenylpropanoid biosynthesis pathway is activated by many plant hosts following infection by fungal pathogens, and the accumulation of autofluorescent material in the stigma 24 h after contact with self pollen strongly indicates this pathway also to be activated after pollination. The timing of this response, however, suggests that phenolic products are unlikely to be involved in the rejection of self pollen. These data are discussed in the perspective of current views of defence systems present in angiosperm epidermal cells, and why these mechanisms fail to identify and reject incompatible pollen tubes.