植物叶硒的时空变异规律研究

本文以加杨叶为主,首次研究了植物叶硒的时空变异规律。得出脱落前夕不久的九、十月份加杨叶能较好地反映大气硒含量水平,而其它生长期的加杨叶则一般主要反映土壤硒的含量状况。此外,还研究得到了一些其它植物老叶硒与环境的关系。

A STUDY ON TIME-SPACE DIFFERENTIATION OF LEAVE SELENIUM

Selenium delficiency in human body is one of the reasons causing Keshan disease and Kaschin-Beck disease. Study on atmospheric affects on leaves is conductive to our overall understanding on transportation of Se in environment-living beings system. Since fuel combustion is the dominant source of Se in air, Se content in air can reflect air quality. Therefore this study is significant for air pollution either,Canadian Poplar leave samples were collected at both polluted urban and clean suburb in Beijing during period of leave sprout to fall In addition poplar and salix old-leave samples were collected from sites distributed from coast to inland representing urban, suburb and countryside. For Se content determination samples were analyzed by DAN fluorescence spectrophotometry after digested by HNO3 - HClO4.Conclusions could be drawn as follows.1. These is a marked drop in leave Se content of poplar in the first twenty days, Afterwards, the Se content remains stable untill two months later when Se content rises gradually. There is a much higher increase in polluted urban than in clean suburb.2. In clean area, leave Se content generally ranges from 0,02-0,2 PPm in populus canadensis, 0.05-0.2PPm in salix. In polluted area, leave Se content can rise to 0.8 PPm in populus Canadensis and 1 PPm in sallix,3, poplar Se content is always lower in stem than in leaves. The stem Se content ranges from 0.01-0.07PPm.