白皮松针叶元素的X射线微区分析

将白皮松(P.bungeana zucc.Ex Endl.)一至四年生针叶分别从尖端、中部和基部截取小段，用扫描电镜X射线微区分析测定各段的表皮、下皮层、叶肉组织和维管组织的元素组成和平均质量分数(ω)，结果发现，针叶中不同年份，不同部位、不同微区的元素组成及其ω是有差异的：一至四年生的白皮松针叶中可测得的元素种类分别为10，8，9，11种；尖端、中部、基部的元素组成相同，但ω有差异，各段K，Ca的ω都较高；分析各个微区，在表皮，Ca，Si，P，S的ω较高，下皮层中K的ω大幅度提高，Mg的ω在叶肉组织中有明显增加；在维管组织中，除K，Ca外其他元素的ω均低于10％，但Fe，Cu的ω明显升高．这些变化与各元素的生理作用有关．研究结果对进一步探讨白皮松针叶的结构和生理特点有重要意义．

X RAY MICROANALYSIS OF THE ELEMENTAL COMPOSITION IN THE NEEDLE LEAVES OF P.BUNGEANA ZUCC. EX ENDL.

The elemental composition and average mass fraction in the needle of P.bungeana Zucc. Ex Endl are analysed by SEM X ray microanalysis method. The result showes that the elemental composition and average mass fraction in the needle vary with years,positions and microzones. In the needles of one to four years old, the kinds of element detecteded are 10,8,9,11,respectively. And in the tip,middle and base of the needle,though the element composition is the same, the average mass fracions of different elements are various, in which K and Ca are the highest in all of the three position. According to the microzone,Ca,Si,P and S are high in the surface layer; in the hypoderm,the content of K rises evidently;Mg increases obviously in the mesophycl tissue,and in the vascular tissue all of elemental average mass fractions are below 10% except K and Ca, where the relative content of Fe and Cu increases obviously. The differences above are related to the physiological function of different elements. The result is valuable in studing the structure and physiological characteristics of P.bungeana Zucc. Ex Endl.