不同海拔地区紫外线B辐射状况及植物叶片紫外线吸收物质含量的分析

ANALYSIS OF THE SOLAR UV-B RADIATION AND PLANT UV-B-ABSORBING COMPOUNDS IN DIFFERENT REGIONS

对不同海拔地区的太阳 UV- B辐射和植物叶片的光学特性进行了比较研究。结果表明 :位于高海拔地区的海北高寒草甸生态系统定位站 ,太阳 UV- B辐射明显高于相近纬度的西宁、兰州和南京地区。UV- B辐射与总辐射和 PAR的日变化规律相似 ,都受太阳高度角的直接影响 ,在当地太阳正午时最高。UV- B/Q的日变化也为单峰曲线 ,海北站地区的 UV- B/Q高于西宁的同期测定结果。对珠芽蓼等植物的研究表明 ,生长于海北站地区的珠芽蓼 ,其叶片中紫外线吸收物质的含量明显高于西宁的同种植物 ,也略高于海拔较高的达坂山和小达坂山山顶的同种植物。叶绿素含量以海北站珠芽蓼最低 ,达坂山和小达坂山的同种植物最高。珠芽蓼叶片中类胡萝卜素的含量以西宁最低 ,海北站、达坂山和小达坂山依次升高。海北站矮嵩草与从海北站移植到西宁生长 4年的同种植物相比 ,叶片中紫外线吸收物质、叶绿素。

The solar UV B radiation was measured at different elevation regions,Haibei Alpine Meadow Ecosystem Research Station(E1 3200m),Xining Northwest Plateau Institute of Biology(El 2300m),Lanzhou Gaolan Agricultural Ecology Research Station(El 1800m),and Nanjing Meteorological Academy(El 32m).The results show that the solar UV B radiation intensity was higher in Haibei Research Station region than in Xining,Lanzhou and Nanjing in June 1993. Diurnal variation of UV B had the same trend as total solar radiation and PAR,which were all influenced by solar angle and higher at the local sun noon time. UV B/Q is the value of solar UV B radiation to total solar radiation.The daily change UV B/Q also had one peak,and the peak value in Haibei was higher than that in Xining. In spite of influence of elevation above sea level,the cloud coverage and aerosols and haze were the main factors influencing the solar UV B radiation on the earth's surface. The characteristics of optical properties of plants reflect the adaptation capacity of plants to solar UV B radiation.The studies of Kobresia humilis and Polygonum viviparum indicate that alpine plants had some adaptation to higher solar UV B radiation intensity.The content of UV B absorbing compounds in P.viviparum collected from Heibei was obviously higher than that from Xining,so was that from the top of Daban Mt. and XiaoDaban Mt., although they were higher in altitude than Haibei Research Station.The total chlorophyll content was lowest in Haibei,but was highest in Daban Mt.and XiaoDaban Mt..The content of carotenoid in P viviparum collected from Xining was the lowest,and the content increased form Haibei Research Station,Daban Mt.to XiaoDaban Mt.The UV B absorbing compounds,chlorophyll and carotenoid in K humilis collected from Xining and Haibei had the same trend as P viviparum collected from the same regions.