关键词: 硒, 叶硒, 加杨

Abstract: 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.

Key words: Selenium, Laeve selenium, Candian Poplar