5个桃砧木品种对淹水胁迫的生理响应及耐涝性评价

【目的】探究不同品种桃树砧木对淹水胁迫的生理响应及耐涝性，为桃耐涝砧木品种选育及抗涝机理提供理论依据。【方法】以毛桃、抗砧1号、浙砧1号、筑波6号、南京白沙5个桃砧木当年生实生苗为供试材料，设正常水分（对照，CK）和淹水处理，测定叶片的光合特性、抗氧化酶活性、光合色素及渗透调节物质含量等指标，综合评价砧木耐涝性。【结果】淹水处理下，各砧木叶片的净光合作用（Pn）和蒸腾速率（Tr）均显著低于CK（P<0.05，下同）；抗砧1号、筑波6号和毛桃叶片的气孔导度（Gs）较CK显著降低；浙砧1号的胞间二氧化碳浓度（Ci）较CK显著下降，其他品种不同程度上升。筑波6号、抗砧1号、南京白沙和毛桃的叶绿素a（Chl a）和类胡萝卜素（Car）含量较CK显著下降。浙砧1号的超氧化物歧化酶（SOD）、过氧化氢酶（CAT）、脯氨酶（Pro）和可溶性蛋白（SP）含量较CK显著提高，丙二酶（MDA）含量显著低于CK；毛桃的过氧化物酶（POD）、CAT及Pro活性显著提高，而SOD活性和（SP）含量显著下降。各种砧木的POD、CAT和Pro的耐涝系数均大于100.00%，Pn、Tr、Chl a、Chl b和Car的耐涝系数均小于100.00%。利用主成分及隶属函数等多元统计方法对15个指标耐涝系数进行综合分析，浙砧1号综合耐涝评价值D值最大，为0.760，表现出较强的耐涝性，其次为南京白沙、筑波6号和抗砧1号，耐涝性中等，毛桃D值最小，为0.091，耐涝性最弱。【结论】淹水胁迫不同程度抑制了砧木叶片光合作用和光合色素合成，各砧木在胁迫下调节体内渗透物质和抗氧化酶能力不同，耐涝性存在差异。在涝害频发的区域应避免桃园积水并采用耐涝性较好的砧木品种。

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.) Batsch]and NanjingbaishaP. persica(L.) Batsch]were 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.