Physiological responses and waterlogging tolerance evaluation of five peach rootstock varieties under waterlogging stress

【Objective】To investigate physiological responses and waterlogging tolerance evaluation of five peach rootstock varieties under waterlogging stress, so as to provide references for breeding of waterlogging-tolerant varieties and further research on waterlogging-tolerant mechanisms of peach.【Method】Five peach rootstocks varieties, MaotaoPrunus persica(L.) Batsch, Kangzhen 1P. persica(L.) Batsch, Zhezhen 1P. persica(L.) Batsch, Tsukuba 6P. persica(L.) Batschand NanjingbaishaP. persica(L.) Batschwere used as the experimental materials. Normal water treatment(CK) and waterlogging treatment were set to determine parameters such as photosynthetic characteristics, antioxidant enzyme activity, chlorophyll content and osmotic adjustment substance content in leaves to comprehensively eva-luate waterlogging tolerance of rootstocks.【Result】Under waterlogging treatment, net photosynthesis(Pn) and transpiration rate(Tr) of all rootstock varieties were significantly lower than those of the control(P<0.05, the same below). Stomatal conductance (Gs) of leaves of Kangzhen 1, Tsukuba 6 and Maotao were significantly lower than those of the control. Intercellular CO₂ concentration(Ci) of Zhezhen 1 decreased significantly compared with that of CK, while the parameters of other varieties increased differently. Content of chlorophyll a(Chl a) and carotenoid(Car) Tsukuba 6, Kangzhen 1, Nanjingbaisha and Maotao were significantly decreased compared with CK. Superoxide dismutase(SOD) activity, catalase (CAT) activity, proline(Pro) content and soluble protein(SP) content of Zhezhen 1 increased significantly compared with CK, and the Malonic dialdehyde(MDA) content was significantly lower than that of CK. Waterlogging tolerance coefficient of perxidase (POD) activity, CAT activity and Pro content significantly increased, while SOD activity and SP content significantly decreased. Waterlogging tolerance coefficients of POD activity, CAT activity and Pro content of various rootstocks were higher than 100.00%, while those of Pn, Tr, Chl a, Chl b and Car were lower than 100.00%. Using multivariate statistical methods such as principal components and membership functions to comprehensively analyze the waterlogging tolerance coefficients of 15 indicators, the comprehensive waterlogging tolerance evaluation value D of Zhezhen 1 was the largest at 0.760, showing strong waterlogging tolerance, followed by Nanjingbaisha, Zhubo 6 and Kangzhen 1, with moderate waterlogging tolerance, and peach with the lowest D value of 0.091, showing the weakest waterlogging tolerance.【Conclusion】Waterlogging stress inhibits rootstock leaf photosynthesis and chlorophyll synthesis differently, rootstocks have different abilities to regulate osmotic substances and antioxidant enzymes under stress and there are differences in waterlogging tolerance. In areas where waterlogging occur frequently, water accumulation in peach orchards should be avoided and rootstock varieties with better waterlogging tolerance should be used.