Effects of Photosynthetic and Biological Characteristics of Cigar Wrapper Tobacco in Different Levels of Nitrogen

Chlorophyll contents,net photosynthetic rates and chlorophyll fluorescence parameters of the cigar wrapper tobacco were measured to study the differences of photosynthetic characteristics under different levels of nitrogen fertilizer.The results showed that the Chlorophyll contents of tobacco leaves were increased with the increasing rates of nitrogen,and so were the PSⅡ potential activation,the maximal quantum efficiency and qp of PSⅡ of tobacco leaves,and then stimulated the photosynthetic rates.And the photosynthetic capability of tobacco leaves was improved and the net photosynthetic rates were increased with increasing the rates of nitrogen fertilizer properly,but the photochemical quenching coefficient and ΦPSⅡ were decreased by high nitrogen level.The dry weight of the plant,the area and the total N content of leaf were increased with increasing the levels of nitrogen,but there was no significant difference between N20 and N15.