不同耐旱性大麦品种叶片发育的研究

Development of the leaves in two different types of drought-tolerant barley

选用耐旱性不同的两个大麦品种作为研究对象,分析其叶片结构的异同。结果表明:两个大麦品种的叶片发育可以分为幼叶萌发期、幼叶抽出期、幼叶生长期和叶片成熟期四个阶段,其中在幼叶萌发期,叶片结构无明显差异。经PAS染色,从幼叶生长期开始,耐旱性弱的Moroc 9-75,含淀粉粒的叶肉细胞少,淀粉粒颗粒小;耐旱性强的HS 41-1,含淀粉粒的叶肉细胞多,淀粉粒颗粒大。遭受干旱胁迫后,两个品种的植株长势明显较弱,叶片短而窄;表皮细胞角质层变厚,叶片中叶肉细胞变小,叶肉细胞胞间隙变大,叶肉细胞破裂现象增多;PAS染色反应显示,含淀粉粒的叶肉细胞减少,淀粉粒颗粒变小或基本没有;HS 41-1解体的细胞不如Moroc 9-75多。因此,在光镜下,叶片结构的差异,特别是细胞含有的淀粉粒大小与数量的区别,是植物对水分胁迫的一种适应;同时叶脉对植物刚性的影响较大。

Two different types of drought-tolerant barley were studied in terms of the similarities and differences of their lamina structures.The study showed that the growth of the two types of lamina experienced 4stages,namely germination stage,sprouting stage,growth stage and mature stage,and that there were no obvious difference in lamina structures in germination stage between the two types of barley.The method of PAS showed that at the germination stage,Moroc 9-75,less tolerant of drought,had fewer mesophyll cells rich in starch grains while the starch grains were small.In the same stage,HS 41-1,more tolerant of drought,had more mesophyll cells rich in starch grains while the starch grains were big.Under drought stress,the two types of barley showed apparent weak growth in height,with short and narrow leaves;the cuticles of epidermis cells thickened,the mesophyll cells of the lamina became smaller,the intercellular space between mesophyll cells grew bigger,and more mesophyll cells split;PAS showed that mesophyll cells with starch grains decreased in number and that starch grains became smaller or disappear;more cells of Moroc 9-75broke down than those of HS 41-1.In conclusion,under optical microscopes,the differences in lamina structures,especially the differences in the size and the number of the starch grains that the cells contained,were the adaptation of plants to drought stress.Besides,the veins had great effects on the hardening of plants.