鄂尔多斯高原不同生境条件下中间锦鸡儿植物叶片表皮特征及遗传多样性变化分析

CHANGES OF CHARACTERISTICS OF THE LEAF EPIDERMIS AND GENETIC DIVERSITY OF CARAGANA DAVAZAMCII IN DIFFERENT HABITATS IN ERDOS PLATEAU,CHINA

该研究在鄂尔多斯高原从东到西按照降雨量逐渐减少的梯度选取了5个地区,对中间锦鸡儿(Caragana davazamcii)叶片的表皮结构进行了比较观察,发现不同生境条件下的中间锦鸡儿由于环境的长期作用表皮表现出一定的差异性,主要表现在随着多年平均降雨量的减少叶片表皮毛密度、气孔密度、气孔指数均有所增加,气孔深陷程度逐渐加深,角质层由光滑变得粗糙,但并不是线性增加,因此本研究对不同生境的中间锦鸡儿植物叶片做了遗传多样性分析,发现随着生境由东向西的变化,中间锦鸡儿种群遗传多样性有增加的趋势,与表皮形态特征变化一致,说明中间锦鸡儿呈现明显的表现型可塑性,可塑性反应比较高。

Aims Although Caragana davazamcii is an important nitrogen-fixing plant in North China,few studies have focused on its epidermal structure and genetic diversity along a precipitation gradient.Our aims are to determine how changes of epidermal structure of C.davazamcii leaves are related to changes of genetic diversity in different habitats,what role environments play in this relationship,and whether these populations have potential to become adapted to their local environments in different ways.Methods We established 20 m×20 m plots along the precipitation gradient and randomly collected leaves of C.davazamcii from natural populations.We studied leaf epidermal structure using a light microscope（LM）and a scanning electron microscope（SEM）and used ISSR-PCR genetic diversity analysis to study differentiation among populations.Important findings The leaf epidermis of C.davazamcii in different habitats was significantly different as a result of environmental effects.Trichome density,stomatal density,stomatal index and cuticle coarseness increased with changes in average annual rainfall from east to west,as did genetic diversity of populations.Caragana davazamcii showed significant phenotypic plasticity in different habitats,and this may play a critical role in the ecological adaptability of C.davazamcii populations.