Influences of Drought and Enhanced UV-B Radiation on the Photosynthetic Pigment of Fagopyrum dibotrys

[Objective] To study the influences of drought stress and enhanced UV-B radiation on photosynthetic pigment of Fagopyrum dibotrys(D.Don) Hara,so as to provide a theoretical basis for the cultivation of F.dibotrys.[Method] By experiment of potted plant,the photosynthetic pigments of F.dibotrys under different drought stresses and UV-B radiations were determined and its ratio was calculated.[Result]Chlorophyll a,chlorophyll b,total chlorophyll,carotenoid contents and ratio of chlorophyll a/streophyll b in F.dibotrys reduced with the severity of drought.Ratios of carotenoid to chlorophyll in F.dibotrys showed a rising trend with the deepening drought and reached a significant level at the later stage.Under conditions of adequate water,enhanced UV-B radiation significantly reduced chlorophyll a,chlorophyll b and total chlorophyll contents in F.dibotrys,and it also significantly increased the ratios of carotenoid/chlorophyll in F.dibotrys.Under conditions of drought stress,enhanced UV-B radiation increased chlorophyll b and total chlorophyll contents in F.dibotrys.[Conclusion] Photosynthetic pigment of F.dibotrys was sensitive to drought stress,and indicative of the injury of leaves to a certain extent,and can reflect the drought of soil.The changes caused by drought stress in photosynthetic pigment of F.dibotrys could be reduced by enhanced UV-B radiation.