琥珀酸黄杆菌促生机理及其对多年生黑麦草生长和抗逆性的生理调控作用

为探究琥珀酸黄杆菌（Flavobacterium succinicans）对非生物胁迫下多年生黑麦草（Lolium perenne）的缓解效应，本试验研究了菌株DSM4002的生物学特性，并在盆栽条件下，分析了干旱（维持相对含水量（30±5）%处理7 d和14 d）、低温（4℃处理3 d和7 d）和盐胁迫（150 mM NaCl处理5 d和10 d）下根际接种DSM4002对多年生黑麦草生长和生理特性的影响。结果表明，DSM4002具有分泌吲哚乙酸（Indole-3-acetic acid，IAA）、溶磷和产铁载体能力，对壮观霉素、卡那霉素等具有抗性，对氯霉素敏感。同时，接种DSM4002能够提高正常生长、干旱、低温和盐胁迫下多年生黑麦草的生物量、抗氧化酶活性、可溶性糖和脯氨酸含量，降低相对电导率和丙二醛（Malondialdehyde，MDA）含量。综上，琥珀酸黄杆菌促进多年生黑麦草的生长与其自身具有分泌IAA、溶磷和产铁载体能力有关，而且它能够调节植物体内氧化还原平衡，从而增强多年生黑麦草的抗旱、抗寒和抗盐能力。

Growth Promotion Mechanisms of flavobacterium succinicans and Their Physiological Regulation on the Growth and Stress Tolerance in Lolium perenne

In order to investigate the alleviating effects of Flavobacterium succinicans on Lolium perenne under abiotic stress, the biological characteristics of strain DSM4002 were studied. The effects of drought ((30±5)% relative water content for 7 d and 14 d), low temperature (4℃ for 3 d and 7 d) and salt stress (150 mM NaCl for 5 d and 10 d) on the growth and physiological characteristics of perennial ryegrass were also analyzed inoculating with DSM4002 or not in the rhizosphere under pot culture conditions. The results showed that DSM4002 had the capacity of secreting indole-3-acetic acid (IAA), dissolving phosphorus and producing iron carriers. It resists to spectinomycin, kanamycin, ampicillin, gentamicin, streptomycin and tetracycline, and is sensitive to chloramphenicol. Meanwhile, DSM4002 inoculating increased the biomass, antioxidant enzyme activities, soluble sugar content and proline content of perennial ryegrass under normal growth, drought, low temperature and salt stress, and decreased the relative electrical conductivity and malondialdehyde (MDA) content. In conclusion, the growth promotion effects on perennial ryegrass by F. succinicans is related to its ability of secreting IAA, dissolving phosphorus and producing iron carriers, and regulating the redox balance in plants, thus enhancing the drought, cold and salt resistance of perennial ryegrass.