Alleviating effects of exogenous catechin on cold damage to tobacco seedlings and its mechanisms of action

To explore the alleviating effects and mechanisms of catechin on the growth and development inhibition of tobacco seedlings under low temperature stress, flue-cured tobacco Xiangyan 7 seedlings sprayed with catechin under low-temperature stress treatments were analyzed to clarify the changes in phenotype, physiological and biochemical indexes and the stress resistance genes of tobacco leaves. The results indicated that the contents(mass fractions)of hydrogen peroxide(H₂O₂), superoxide anion(O₂^-·) and malonaldehyde(MDA)were significantly increased in the tobacco leaves under low-temperature stress. After the application of catechin, the activities of superoxide dismutase(SOD)and catalase(CAT)were raised and the accumulation of reduced glutathione(GSH)was promoted, which resulted in significantly reduced contents of H₂O₂, O₂^-·and MDA. The expression of stress related genes such as CORs, ERDs and Rab28 in the leaves sprayed with catechin under low-temperature stress was significantly up regulated. Evidently, exogenous catechin application enhances cold tolerance and alleviates the effects of low temperature stress on the growth of tobacco seedlings.