黄花苜蓿叶片解剖结构对盐碱胁迫的响应

The Anatomical Stucture Responses in Medicago falcata L.Leaves to Saline-alkali Stress

为探讨盐碱胁迫下黄花苜蓿叶片结构的特征变化,揭示解剖结构与其耐盐碱的关系,采用石蜡切片法对龙牧18黄花苜蓿在150 mmol/L NaHCO3和Na2CO3混合盐碱胁迫0、1、6 h和12 h后的叶片解剖结构进行观测,测定叶片的厚度、栅栏组织厚度、海绵组织厚度、上表皮厚度、下表皮厚度等,计算栅海比、栅栏组织紧密度和海绵组织疏松度,研究不同盐碱胁迫时间对黄花苜蓿叶片结构的影响。结果表明,盐碱胁迫对黄花苜蓿叶片表皮结构、叶肉组织具有显著影响,盐碱胁迫下龙牧18黄花苜蓿叶片的栅栏组织厚度、海绵组织厚度对叶片厚度起主导作用。对上述指标标准化并进行主成分分析,龙牧18黄花苜蓿盐碱胁迫时提取特征值>1的3个主成分,累计方差贡献率达83.523%。

In order to investigate the characteristic changes of leaf structure of Medicago falcata L.under saline-alkali stress and reveal the correlation between anatomical structure and saline-alkali resistance,the leaf anatomical structure of M.falcata L.cv.Longmu No.18 was observed by paraffin wax method after 0,1,6 h and 12 h of 150 mmol/L NaHCO3 and Na2CO3 mixed saline-alkali stress.The paraffin wax method was used to measure the leaf thickness,palisade tissue thickness,spongy tissue thickness,epicuticle thickness and hypodermis thickness.The ratio of palisade tissue to spongy tissue,tightness of leaves palisade tissue structure and looseness of leaves sponge tissue structure were calculated to study the influence of different saline-alkali stress time on leaf structure of M.falcata L..The results showed that the saline-alkali stress significantly influenced the skin and mesophyll structure of the leaves.The thickness of M.falcata L.cv.Longmu No.18 leaves depend on palisade tissue thickness and spongy tissue thickness.The above indexes were standardized and principal component analysis was conducted to extract three principal components with the characteristic value greater than 1 of M.falcata L.cv.Longmu No.18 under saline-alkali stress,whose cumulative variance contribution rate was 83.523%.