Effect of different types of organic acids and their combined application on the growth and leaf non-enzymatic active oxygen metabolism of flue-cured tobacco

The effects of different types of organic acids and their combined application on the growth and leaf non-enzymatic active oxygen metabolism of flue-cured tobacco were studied.The results showed that applying organic acids accelerated the plant height,the largest leaf length and width,the dry weight of steam and leaf,the dry weight of root to promote the growth of flue-cured tobacco,single application of oleic acid or malic acid,combined application of malic acid and oleic acid,or combined application of malic acid,oleic acid and humic acid had most obvious influence on it.Moreover,applying organic acids increased the content of ascorbic acid(ASA) and reduced glutathione(GSH),decreased the accumulation of superoxide radical(O-2·),which were beneficial for the balance of the leaf non-enzymatic active oxygen metabolism of tobacco.The results indicated that humic acid and oleic acid were most effective in single application of organic acids,the production rate of O-2· reduced by 35.33% and 37.08% than the control,the content of ASA increased by 28.64% and 36.03%,the content of GSH increased by 19.75% and 15.24%;combined application of malic acid and humic acid,or combined application of malic acid and oleic acid were most effective in combined application of organic acids,the production rate of O-2· reduced by 31.00% and 29.96% than the control,the content of ASA increased by 28.31% and 34.05%,the content of GSH increased by 13.87% and 10.18%.