Effects of light intensity on photosynthetic capabilities, growth and quality of flue-cured tobacco

This paper examined the growth,photosynthetic capabilities and chemical composition of flue-cured tobacco under full light(100%) and light intensity at the transmittances of 80%,50% and 20%.The results showed that:(1)With the reducing light intensity,tobacco stems became slender,the ratio between leaf long and wide increased,the number of leaves and total dry matter decreased.The plant height and leaf area under 80% full light condition were significantly higher than those under the other light intensity.(2) Photosynthetic indicators of Pn,Gs,Tr,Chl a/b decreased under low light,but Ci and chlorophyll contents increased,as well as fluorescence parameter of Fm,ФPSⅡ,Fv/Fm,QP.(3) As the reducing light intensity,starch content,reducing sugar content,total sugar and total phenol content lowed and total N and K content increased.