桃色欧文氏菌Cp2粉红色素对紫花苜蓿种子萌发及幼苗生长生理的影响

Effects of pink pigment from Erwinia persicinaCp2 on seed germination and seedling growthphysiology of Medicago sativa

摘要:

【目的】 探究桃色欧文氏菌（Erwinia persicina）Cp2 粉红色素对紫花苜蓿种子萌发及幼苗生长的影响。【方法】 以紫花苜蓿（Medicago sativa）品种巨能 551 为试验材料，使用不同浓度（0、0. 094、0. 188、0. 282、0. 376、0. 470 mg/mL）的Cp2 粉红色素处理紫花苜蓿，并测定紫花苜蓿种子萌发、幼苗生长及生理相关指标。【结果】 1）Cp2 粉红色素对紫花苜蓿种子萌发没有显著影响；2）Cp2 粉红色素对紫花苜蓿幼苗的生长呈现出浓度效应：随着Cp2 粉红色素浓度的增加，紫花苜蓿幼苗叶片黄化、整株萎蔫的症状愈加明显，且紫花苜蓿幼苗根系向着渐短渐粗的趋势发展、叶绿素含量较CK 显著降低。0. 470mg/mL 处理使紫花苜蓿幼苗根系长度和叶绿素含量降至最低，叶片相对电导率达到最高（P＜0. 05）；3）与对照相比，Cp2 粉红色素致使紫花苜蓿幼苗超氧化物歧化酶（SOD）和过氧化氢酶（CAT）的活性显著降低；0. 188~0. 470 mg/mL 处理诱导紫花苜蓿幼苗体内超氧阴离子（O₂-）、过氧化氢（H₂O₂）及丙二醛（MDA）的含量较CK 显著升高；4）相关性分析和主成分分析结果表明不同浓度的Cp2 粉红色素致使紫花苜蓿幼苗的生长较CK 产生了实质性差异，这种差异主要体现在对紫花苜蓿幼苗根系生长的抑制、降解叶绿素、抑制抗氧化酶的活性等方面。【结论】 桃色欧文氏菌Cp2 分泌的粉红色素能够显著抑制紫花苜蓿幼苗的生长发育，该结果为揭示桃色欧文氏菌Cp2 的致病机理及紫花苜蓿细菌性病害的防治奠定了理论依据。

Abstract:

【Objective】 This study investigates the effects of the pink pigment produced by Erwinia persicinaCp2 on seed germination and seedling growth physiology in alfalfa （ Medicatgo sativa‘ Juneng 551’）.【Method】 Differentconcentrations of Cp2 pink pigment （0，0. 094，0. 188，0. 282，0. 376，0. 470 mg/mL） were applied to alfalfaseeds，and various indicators related to germination，seedling growth and physiological characteristics were measured.【Result】 The findings indicate that：1） Cp2 pink pigment did not significantly affect seed germination. 2） There was aconcentration-dependent effect on seedling growth；with the increase of Cp2 pink pigment concentration，symptomsof leaf yellowing and wilting became more pronounced. The root systems of alfalfa seedlings tended to be shorter and thicker，with significantly lower chlorophyll content compared to the control（CK）. The root length and chlorophyllcontent decreased to their lowest levels，whilethe relative electrical conductivity of leaves peaked at the 0. 470mg/mL treatment. 3） Compared to the control，Cp2 pink pigment significantly decreased the activities of superoxidedismutase and catalase in alfalfa seedlings. Treatments at concentrations of 0. 188~0. 470 mg/mL induced significantincreases in superoxide anion，hydrogen peroxide，and malondialdehyde levels. 4） Correlation and principal componentanalyse srevealed substantial differences in seedling growth due to different concentrations of Cp2 pink pigment，primarily reflected in the inhibition of root growth，chlorophyll degradation，and reduced antioxidant enzyme activities.【Conclusion】 In summary，the pink pigment secreted by Erwinia persicina Cp2 significantly inhibits the growth anddevelopment of alfalfa seedlings. These results provides a theoretical foundation for understanding the pathogenicmechanism of Erwinia persicina Cp2 and for developing control strategies against bacterial disease in alfalfa.