Pectin secretion and distribution in the anther during pollen development in Lilium
Pectin secretion and distribution in the anther during pollen development in Lilium
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DOI：
10.1007/s004250000469
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发表时间：
2001-05-01
期刊：
影响因子：
4.3
通讯作者：
Clément, C
中科院分区：
文献类型：
--
作者：
Aouali, N;Laporte, P;Clément, C
利用单克隆抗体JIM 5和JIM 7对百合花粉发育过程中的3个花药室中的果胶进行了免疫定位和定量分析。花粉囊壁和药室中的果胶水平在减数分裂后增加，在小孢子早期达到最高，在花粉个体发育的其余阶段下降。在小孢子/花粉粒中，果胶在小孢子阶段以低水平检测到，但在花粉成熟过程中积累显着。在小孢子液泡化早期，绒毡层细胞质和液泡中都检测到酯化果胶抗原决定簇。在药室中，相同的表位同时位于质膜的起伏处和药室液中。在小孢子液泡化结束时，酯化果胶表位存在于花粉囊的脂质中，并在花粉有丝分裂时释放到室中。未酯化的果胶抗原决定簇在年轻的小孢子的细胞质中几乎检测不到，但丰富的primexine矩阵中的室。在花粉成熟过程中，未酯化和酯化果胶标记积累在营养细胞的细胞质中，同时淀粉降解。在成熟花粉粒中，未酯化的果胶表位位于近端内壁，而酯化的果胶表位沉积在远端内壁。这些数据表明，在早期小孢子发育，绒毡层分泌果胶，这是转移到primexine矩阵通过室液。此外，果胶被证明是百合成熟籽粒中花粉碳水化合物储备的重要组成部分。
Using the monoclonal antibodies JIM 5 and 7, pectin was immunolocalized and quantitatively assayed in three anther compartments of Lilium hybrida during pollen development. Pectin levels in both the anther wall and the loculus increased following meiosis, were maximal during the early microspore stages and declined during the remainder of pollen ontogenesis. In the microspores/pollen grains, pectin was detectable at low levels during the microspore stages but accumulated significantly during pollen maturation. During early microspore vacuolation, esterified pectin epitopes were detected both in the tapetum cytoplasm and vacuoles. In the anther loculus, the same epitopes were located simultaneously in undulations of the plasma membrane and in the locular fluid. At the end of microspore vacuolation, esterified pectin epitopes were present within the lipids of the pollenkitt, and released in the loculus at pollen mitosis. Unesterified pectin epitopes were hardly detectable in the cytoplasm of the young microspore but were as abundant in the primexine matrix as in the loculus. During pollen maturation, both unesterified and esterified pectin labelling accumulated in the cytoplasm of the vegetative cell, concurrently with starch degradation. In the mature pollen grain, unesterified pectin epitopes were located in the proximal intine whereas esterified pectin epitopes were deposited in the distal intine. These data suggest that during early microspore development, the tapetum secretes pectin, which is transferred to the primexine matrix via the locular fluid. Further, pectin is demonstrated to constitute a significant component of the pollen carbohydrate reserves in the mature grain of Lilium.