云南干热河谷不同居群坡柳叶片的旱生结构比较

Comparison of leaves anatomical structures and related drought resistance among different populations of Dodonaea viscosa in Yunnan hot- dry valley

坡柳是云南干热河谷植被恢复的先锋树种,具有极高的抗干热和耐贫瘠的特点,不同河谷水热条件的差异是否对其抗旱能力和旱生结构产生影响值得研究。采用常规石蜡切片和光学显微镜技术,运用隶属函数法,对金沙江河谷、元江河谷和澜沧江河谷坡柳叶片解剖结构的研究表明:3个河谷坡柳叶片的解剖结构特征存在差异,下表皮细胞厚度、角质层厚度、叶片组织结构疏松度(SR)指标表现为元江河谷抗旱能力最强,体现了温度对坡柳叶片解剖结构的影响;叶片厚度、上表皮细胞厚度、栅栏组织厚度、海绵组织厚度、叶片组织结构紧密度(CTR)指标表现为金沙江河谷抗旱能力最强,体现了干旱程度对坡柳叶片解剖结构的影响。结合解剖结构,利用隶属函数法分析得出各居群坡柳的旱生能力强弱依次为:金沙江河谷>元江河谷>澜沧江河谷,这与三个河谷的干燥度基本一致。分析发现干热河谷坡柳的旱生结构与西北地区典型旱生植物具有较高的相似性。

Dodonaea viscosa is a pioneer species of vegetation restoration in dry- hot valleys（ DHV） of Yunnan.It has high resistance to drought,hot and barren. However,different valleys have different thermo- moisture condition. How those differences affect the xerophytic structure and drought resistant capacity of Dodonaea viscosa has not been reported. An anatomical comparative study was conducted with the objective to compare the anatomical structure by using paraffin method,optical microscope technology and subordinate function methods to observe different populations of Dodonaea viscosa. The materials were from Jinsha River Valley,Yuanjiang River Valley and Lancang River Valley. The results showed that the anatomical structure of leaves of three valleys of Dodonaea viscosa were different,the thickness of lower epidermis,cuticle layer and spongy ratio showed that the plant from Yuanjiang River Valley had the strongest drought resistance,and also showed that different temperature can lead to a different influence on anatomical structure of leaves of Dodonaea viscosa; the thickness of leaf,upper epidermis,palisade tissue,spongy tissue and cell tense ratio showed that the plant from Lancang River Valley had the strongest drought resistance and different degree of drought can induce a different influence on anatomical structure of leaves of Dodonaea viscosa. On account of the anatomical structure of leaves,using the subordinate function method to comprehensively evaluate these three valleys of Dodonaea viscosa,the result indicated that the drought resistance capability decreased in sequence of Jinsha River Valley,Yuanjiang River Valley,Lancang River Valley,it was the same as the aridity index. Analysis showed that the xerophytic structure of Dodonaea viscosa in dry- hot valley（ DHV） had a very high similarity with the typical xerophytic plants in the northwest of China.