Reaction of tobacco to oxidation stress induced by topping and bionic signal molecules
To investigate whether the mechanical injury on tobacco by topping induces oxidation stress, the contents of superoxide anion (O2-•), hydrogen peroxide (H2O2) and malondialdehyde (MDA) and the activity of superoxide dismutase (SOD) in leaf tissue were determined and their changes were analyzed and compared with untopped control in a period of time after topping. Bionic signal molecules (BSM) was immediately applied to the plants’ top after topping, and relative biochemical indexes were measured. The results showed that topping would stimulate the oxidation stress. Exogenous BSM treatment would inhibit oxidation stress induced by topping, reduce the accumulation of O2-•, H2O2, MDA in tobacco leaves, and improve the activity of SOD. BSM restricted the synthesis of jasmonic acid by inhibiting oxidation stress, and further reduced the accumulation of alkaloids in topped tobacco plant.