【摘要】 小叶锦鸡儿(Caragana microphylla Lam.)、中间锦鸡儿(Caragana intermedia Kuang er H.C.Fu)和柠条锦鸡儿(Caragana korshinskii Kom.)是内蒙古高原锦鸡儿属(Caragana Fabr.)从东到西分布的3个地理替代种,均为多年生灌木,具有重要的生态和饲草价值.选取内蒙古高原自然分布的4个小叶锦鸡儿种群、7个中间锦鸡儿种群和2个柠条锦鸡儿种群,利用扫描电镜对其叶表皮特征进行观察测定,并结合气侯因子、土壤因子分析环境对锦鸡儿叶表皮特征分化的影响.结果显示,3种锦鸡儿都密被表皮毛,气孔下陷,具有角质层,为旱生特征. 13个种群叶片上表皮的表皮毛密度、气孔密度、气孔指数平均值(±标准误)分别为212.44 (±127.80)个/mm~2、309.40 (±103.38)个/mm~2、10.17 (±3.21),叶片下表皮分别为184.60 (±132.74)个/mm~2、254.20 (±112.83)个/mm~2、9.66 (±4.03).从东到西分布的3种锦鸡儿,表皮毛密度呈现增加趋势,上表皮气孔密度呈下降趋势.种群间表皮毛密度、气孔密度、气孔指数和气孔大小都有明显差异(P<0.05),小叶锦鸡儿和中间锦鸡儿的表皮毛密度变化最大,其次为气孔密度,而柠条锦鸡儿的表皮毛密度变化最小,气孔指数及密度变化较大.环境差异对3种锦鸡儿的表皮毛密度、气孔大小及分布影响较大,但不同类型锦鸡儿对环境变化的敏感程度不同,采取了不同的对策以适应干旱环境.逐步回归分析表明,年均降水量、有效积温、日照时数、土壤全氮、土壤全磷和土壤有机碳对表皮微形态特征变化有显著影响(P <0.05).本研究表明3种锦鸡儿叶表皮的微形态特征受气候环境因子显著影响,同时为应对环境变化产生了适应分异;结果可为预测全球气候变化背景下植物的适应机制及保护利用提供理论依据.(图5表8参46)更多还原

【Abstract】 Caragana microphylla, Caragana intermedia, and Caragana korshinskii are perennial shrubs and geographically alternative species distributed from East to West on the Inner Mongolia Plateau. The species are of great significance in ecology and have a high forage value. In this study, 13 populations of the three Caragana species were observed with a scanning electron microscopy(SEM), and the effects of climatic factors and soil factors on the differentiation of the leaf epidermis were analyzed. The results showed that three species of Caragana were densely covered with epidermis and stomata with stratum corneum, which are characteristics of drought resistance. From East to West, the three Caragana species demonstrated an increase in density of epidermis hair and a decrease in stomatal density of the upper epidermis. There are apparent differences in leaf epidermis micromorphology among populations which vary with the environmental changes. The stepwise regression analysis showed that annual precipitation, effective accumulated temperature, sunshine hours, total soil nitrogen,total phosphorus, and soil organic carbon have a significant influence on the changes of epidermal micromorphology. The above results showed that the climatic and environmental factors significantly affect the micromorphological characteristics of the epidermis of the three species of Caragana and that the adaptative differentiation takes place in the epidermal micromorphology. This study provides a theoretical basis for predicting the adaptation mechanism, protection, and utilization of plants in the context of global climate change.更多还原