Genetic structure of needle morphological and anatomical traits of Pinus yunnanensis

Pinus yunnanensis Franch. is an particular conifer tree species in Yunnan-Guizhou plateau in south- west China. The morphological and anatomical traits of needles are important to evaluate geographic variation and population dynamics of conifer species. Seedlings from seven populations of P. yunnanensis were analyzed, look- ing at 22 morphological and anatomical needle traits. The results showed that variations among and within popula- tions were significantly different for all traits and the variance components within populations were generally higher than that among populations in the most tested needle traits. The proportions of three-needle fascicle were significantly different among populations. The traits related to needle size in both morphology and anatomy were positive with latitude and negative with annual temperature and precipitation. Ratio indices, including mesophyllarea/vascular bundle area, mesophyll area/resin canals area, vascular bundle area/resin canals area and mesophyU area/（resin canals area and vascular bundle area）, were negatively correlated with elevation and positively corre- lated with the annual mean temperature, showing some fitness feature for the populations. Needle traits were more significantly correlated with longitude than with other four environmental factors. Needle length was significantly correlated with almost all environmental factors. First four principal components accounted for 81.596 % of the variation with eigenvalues 〉1; the differences among populations were mainly dependent on needle width, stomatal density, section areas of vascular bundle, total resin canals, and mesophyll, as well as area ratio traits. Seven populations were divided into three categories by Euclidean distance. Variations in needle traits among the populations have shown systematic microevolution in terms of geographic impact on P. yunnanensis. This study would provide empirical data to characterize adaptation and genetic variation of P. yunnanensis, which would be helpful for management of genetic resources and reason- able utilization of them in future.

植物叶形态解剖结构的简易快捷观测方法筛选

为了解决植物形态解剖结构观测方法中的成本高、耗时多、操作不便等问题,进行了植物叶形态解剖结构简易快捷观测方法的筛选研究,利用各种食用胶的可塑性、透明性和胶粘性等特点来获得植物材料的细胞痕迹,通过显微镜间接观察所取植物材料的解剖结构,为教学和科研工作提供一种简便、快捷的新方法,丰富植物学制片技术。结果表明,明胶适用于叶片表皮和横切面细胞痕迹的制取;徒手切片法适用于叶柄横切面解剖结构的制取,操作简便、观测效果好;95%乙醇用于叶片的脱色效果最好,但先要在梯度浓度为20%、50%、70%的乙醇溶液中各浸泡2h,使叶片逐渐脱水,防止叶片脱水变形。