弱光胁迫下黄瓜幼苗叶片解剖结构及光合特性研究

A Study on the Leaf Anatomical Structure and Photosynthetic Characteristics of Cucumber Seedlings under Low Light Stress

对弱光胁迫下6份弱光耐性不同的黄瓜幼苗的叶片形态结构和光合特性进行研究,弱光光强为100μmol/(m2.s)处理10 d,自然光强为300μmol/(m2.s)。结果表明,不同的材料之间形态结构存在差异,耐弱光性材料组织结构紧密度大,组织结构疏松度小。海绵组织厚度与弱光性呈极显著负相关;组织结构紧密度与耐弱光呈显著正相关;组织结构疏松度与耐弱光性呈显著负相关。即栅栏组织在叶肉中所占比例越大,海绵组织在叶肉中所占比例越小,植物耐弱光性越强,反之,越不耐弱光。黄瓜幼苗叶片的光合特性与耐弱光性(耐弱光指数)有密切的关系,其中光补偿点、CO2饱和点、CO2补偿点与耐弱光指数呈极显著负相关性,相关系数分别为-0.91、-0.95、-0.97;光饱和点与耐弱光指数也呈负相关,但未达到显著性。

Using six cucumber lines, the leaf morphology and photosynthesis characteristics of cucumber seedlings under low light were studied. The cucumber seedlings were treated with low light （ intensity = 100 μmol/m^2 · s） for 10 days. The results showed that leaf morphology was different among these materials; the morphological structure of the low light tolerance cucumber materials had higher compaction degree and smaller osteoporosis degree. Spongy tissue thickness had highly significant negative correlation with low light tolerance. The compaction degree of morphological structure had a significant positive correlation with shading resistance index. The osteoporosis degree of morphological structure had significant negative correlation with shading resistance index. Consequently, in the mesophyll, the more palisade tissue and less spongy tissue proportion implied stronger resistance to low light. The photosynthesis characteristics of cucumber seeding leaves had closed relationship with tolerance of low light （low light tolerance index）. Light compensation point, CO2 saturation point and CO2 compensation point had significant negative correlation with low light tolerance index,the relative index were - 0. 91, - 0. 95, - 0. 97, respectively. Light saturation point also had negative correlation with low light tolerance index, but it was not significant.