芝麻叶腺毛显微结构及干旱条件下腺毛分泌物的变化

Microstructure of Glandular Trichomes on Leaf Surface of Sesame and Changes of Trichome Secretions under Drought Condition

通过扫描电镜观察芝麻苗期叶片表面腺毛的显微结构,以二氯甲烷作为溶剂提取腺毛分泌物,并用GC/MS鉴定正常和干旱条件下不同芝麻品种叶片腺毛次生代谢物的差异。结果显示,苗期芝麻叶片表面存在非腺体腺毛、长柄腺毛、短柄腺毛及无柄黏液毛等多种腺毛类型,叶表面气孔属于毛茛型;芝麻叶腺毛分泌物包含多种组分,其中峰面积>2%的组分是主要代谢物,主要由酯类及直链饱和烷烃物质组成,且品种间具有显著差异;干旱条件下,分泌物的组分显著改变,抗旱性较强的冀9014有10个组分的相对含量高于其他品种,这些组分包含三十六烷与三十四烷类物质。上述结果表明,用GC/MS鉴定芝麻叶表面腺毛分泌物是可行的,分泌物组分可以反映品种间的差异,并能揭示干旱条件对芝麻代谢的影响。可以认为,芝麻腺毛与腺毛分泌物组分在芝麻种质资源鉴定及抗旱种质选育中具有重要的应用价值。

We investigated the microstructure of glandular trichome on sesame leaf surface by scan electron microscope and extracted the trichome secretions using dichloromethane as solvent, and the secretion components under normal and drought conditions were measured by GC/MS to compare the secondary metabolites between sesame varieties. The experiment results indicated that, there were non-glandular hairs, long stalk glandular hairs, short stalk glandular hairs and mucilage hairs on the sesame leaves surface, and the stomata belong to the buttercup type. The secretions of glandular hairs contained a variety of components, of which the main fractions with peak area more than 2% were composed of esters and straight chain saturated alkanes mainly, showing notable differences among four sesame cultivars. Under drought condition, the secreted components changed significantly. Ji 9014 with the highest drought resistance among the four cultivars, had ten components, including C36 alkanes and C34 alkanes, which were higher in Ji 9014 than in other tested cultivars. We can conclude that, the GC/MS technique is feasible to identify the glandular trichome secretions, and the secretion components are good index to reveal differences between varieties and the effects of drought condition on metabolic pathway in sesame leaves. Therefor, the glandular hairs and secretion components have important application values in sesame germplasm identification and molecular breeding for drought-resistant sesame.