Comparison of Drought Resistance Characteristics of Different Flue-cured Tobacco Varieties

Drought resistance of 4 different tobacco cultivars was studied under drought conditions caused by controlling irrigation,some indexes,including the accumulation of the plant,leaf relative water content,water-holding capacity,net photosynthetic rate and ABA content,were screened and evaluated.The results showed that:in arid conditions,both plant fresh and dry mass,leaf relative water content and photosynthetic rate decreased,but the range of 'Yuyan 6'(YY 6)and 'Nongda 202'(ND202)were relactively less;While the contents of MDA and ABA have a significant increase.'NC89' had the most increasing amount of MDA,YY 6 and ND 202 were relatively less.For ABA content,YY 6 had the most increasing amount,'NC89' had the least;YY 6 had higher water-holding capacity than that of 'K326' and 'NC889' in the drought conditions;YY 6 performed stronger drought ability than that of ND 202 and 'NC89' the weakest.The study found that there are obvious differences between flue-cured tobacco genotypes in plant morphometrics and physiological index under the drought stress.The drought resistant varieties showed a higher leaf water retention capacity,the net photosynthetic rate,biomass,abscisic acid content,and a lower MDA content.The physiologic indexes except ABA content varied less under drought stress.