紫花苜蓿叶片受白粉病菌侵染后结构的变化

摘要

为了了解植物细胞结构与抗病性的关系.以豌豆白粉菌(Erysiphe pisi)接种2个抗性不同的紫花苜蓿品种,对接种后0、3、7、10 d的叶片制作了石蜡切片,显微观察叶片细胞横切结构.本研究首次发现:病原菌侵染后,抗病品种庆阳苜蓿叶片栅栏细胞由长圆形变为多个近圆形细胞,细胞分布均匀,排列紧凑,叶肉细胞由侵染前的4～5层变为7～8层细胞;感病品种德宝苜蓿栅栏细胞结构变化向两个方向发展:一是长圆形栅栏细胞变为多个卵圆形小细胞,但细胞分布不匀,部分细胞间出现较大间隙;二是叶片维管束之间的栅栏细胞由长圆形变为卵圆形小细胞,而在维管束处的栅栏细胞仍为长圆形,紧靠维管束,排列在一起,细胞间隙小.%To explore the relationship between plant cell structure and disease resistance,two alfalfa (Medicago sativa) cultivars with different levels of resistance were analyzed after inoculation with the powdery mildew fungus,Erysiphe pisi.Leaves were harvested at 0,3,7,and 10 days after inoculation,embedded in paraffin,and cut into sections to observe cell structural changes.The cellular structure of palisade tissue changed after infection with E.pisi.Palisade cells of the resistant alfalfa line changed from a single long cylindrical cell into several subrotund cells that were distributed evenly and arranged compactly.The mesophyll cell layer increased from 4-5-cells thick before infection to 7-8-cells thick after infection.There were two notable changes in the palisade cell structure of susceptible alfalfa.One was that long cylindrical palisade cells changed into several subrotund cells with a non-uniform distribution and more space between cells.The other was that palisade cells near vascular bundles retained their long cylindrical shape and stayed in a compact arrangement with only small spaces between cells.