Shakya Rashmi, Bhatla Satish Chander
Department of Botany, Miranda House, University of Delhi, North Campus, Delhi, 110007, India.
Sex Plant Reprod. 2010 Jun;23(2):163-72. doi: 10.1007/s00497-009-0125-0. Epub 2009 Dec 15.
Spatial distribution and compositional analyses of the lipidic constituents in pollen and stigma of sunflower (Helianthus annuus L. cv. Morden) were conducted using ultrastructural, histochemical, and biochemical analysis. Detection of secretions at the base of stigmatic papillae and neutral lipid accumulations on the surface of stigmatic papillae and between adjacent pseudopapillae demonstrates the semidry nature of stigma surface in sunflower. Pollen coat is richer in lipids (8%) than stigma (2.2%) on fresh weight basis. Nile Red-fluorescing neutral lipids are preferentially localized in the pollen coat. Neutral esters and triacylglycerols (TAGs) are the major lipidic constituents in pollen grains and stigma, respectively. Lignoceric acid (24:0) and cis-11-eicosenoic acid (20:1) are specifically expressed only in the pollen coat. Similar long-chain fatty acids have earlier been demonstrated to play a significant role during the initial signaling mechanism leading to hydration of pollen grains on the stigma surface. Lipase (EC 3.1.1.3) activity is expressed both in pollen grains and stigma. Stigma exhibits a better expression of acyl-ester hydrolase (EC 3.1.1.1) activity than that of observed in both the pollen fractions. Expression of two acyl-ester hydrolases (41 and 38 kDa) has been found to be specific to pollen coat. Specific expression of lignoceric acid (24:0) in pollen coat and localization of lipase in pollen and stigma have been discussed to assign possible roles that they might play during pollen-stigma interaction.
利用超微结构、组织化学和生化分析方法，对向日葵（Helianthus annuus L. cv. Morden）花粉和柱头中的脂质成分进行了空间分布和成分分析。在柱头乳突基部检测到分泌物，在柱头乳突表面和相邻假乳突之间检测到中性脂质积累，这表明向日葵柱头表面具有半干性。以鲜重计，花粉壁中的脂质（8%）比柱头中的脂质（2.2%）更丰富。尼罗红荧光中性脂质优先定位于花粉壁中。中性酯和三酰甘油（TAGs）分别是花粉粒和柱头中的主要脂质成分。二十四烷酸（24:0）和顺式-11-二十碳烯酸（20:1）仅在花粉壁中特异性表达。类似的长链脂肪酸 earlier been demonstrated 已被证明在导致花粉粒在柱头表面水合的初始信号传导机制中起重要作用。脂肪酶（EC 3.1.1.3）活性在花粉粒和柱头中均有表达。柱头中酰基酯水解酶（EC 3.1.1.1）活性的表达比在两个花粉组分中观察到的更好。已发现两种酰基酯水解酶（41和38 kDa）的表达对花粉壁具有特异性。本文讨论了二十四烷酸（24:0）在花粉壁中的特异性表达以及脂肪酶在花粉和柱头中的定位，以确定它们在花粉 - 柱头相互作用过程中可能发挥的作用。 （注：原文中“earlier been demonstrated”表述有误，推测可能是“has earlier been demonstrated” ，译文按推测修正翻译，但不确定是否准确）
