Effects of graft on lipid peroxidation and antioxidative enzyme activities of Capsicum annum seedlings under low temperature and weak light intensity

Taking 'Chifengtexuan' as scion and 'Weishi' as rootstock, this paper studied the changes in the electrolyte leakage (EL), malondialdehyde (MDA) content, antioxidative enzyme activities, and root activity of own-rooted and grafted Capsicum annuum seedlings under 1-7 days low temperature (8 degrees C/ 5 degrees C) and weak light intensity (100 micromol x m(-2) x s(-1) stress and after 1-3 d recovery. During the early stress days, the EL, MDA content, and activities of superoxide dismutase (SOD), peroxidase (POD), ascorbate peroxidase (APX) and glutathione reductase (GR) in both own-rooted and grafted seedlings leaves and roots increased, but the root activity decreased significantly. 1-3 days later, grafted seedlings showed a stable state in EL and MDA content, a decrease in SOD, POD, APX, and GR activities, and an increasing trend in root activity. After 3 days recovery, the EL, MDA content, antioxidative enzyme activities, and root activity of grafted seedlings reached or exceeded their original levels, except for the MDA content in roots, while the EL and MDA content of own-rooted seedlings were still significantly higher than those before the stress. Comparing with own-rooted seedlings, grafted seedlings showed lower EL and MDA content, higher activities of SOD, POD, APX and GR, and higher root activity during stress and recovery days. These data suggested that graft could effectively decrease the lipid peroxidation, and alleviate the damage of low temperature and weak light intensity to Capsicum annuum seedlings.