普城沙雷菌A21-4根际定殖能力及其对辣椒生长和诱导抗病性的影响

 本文探讨了辣椒疫病生防菌普城沙雷菌A21-4在辣椒根际的定殖能力及其对辣椒的促生长和诱导抗病性影响。以10⁸cfu·mL^-1A21-4菌液处理辣椒苗，A21-4能够有效地定殖在辣椒根际土壤和辣椒根部，移栽第30 d在根际土壤和辣椒根部均保持10⁶cfu·g^-1以上定殖密度。辣椒根际土壤中A21-4的定殖密度和病原菌存在与否无显著差异，而辣椒根部A21-4的定殖密度在病原菌存在时显著高于没有病原菌的；A21-4处理有效促进了辣椒地上部和根部的各项生育指标，同时，显著提高了辣椒叶绿素含量和根系活力。A21-4处理的辣椒苗叶绿素含量和根系活力比对照各提高86.1%和481.8%；经A21-4处理后，辣椒根部和叶部的SOD、POD和PAL活性明显提高，辣椒根部的SOD、POD和PAL活性峰值分别比对照提高44.7%、64.2%和77.0%，辣椒叶部SOD、POD和PAL活性峰值分别比对照提高27.9%、134.9%和87.0%；此外，A21-4浸根处理还能够提高辣椒叶部对辣椒疫霉菌的抗性。

Growth promoting and root colonization ability of Serratia plymuthicaA21-4 and its effect on induced resistance in pepper against Phytophthora blight

The colonization ability of Serratia plymuthicaA21-4 in pepper rhizosphere and its impact on pepper growth and the induced resistance of pepper to Phytophthora capsici were studied. After 30 d ays of inoculation of pepper seedlings with 10 ⁸ cfuL ^-1 bacterial suspension ofA21-4, it was found that there was a relative high population density ofA21-4 at 10 ⁶ cfu·g^-1 in rhizosphere. In rhizosphere soil, co\|inoculation with pathogen didn't affect the colonization density ofA21-4; but in pepper roots, colonization density ofA21-4 was significantly stimulated when pathogen existed. Inoculation withA21-4 significantly enhanced the growth index of pepper, including fresh and dry weight, chlorophyll content and root activity. The chlorophyll content inA21-4 treated pepper plants was increased by 86.1% and root activity was increased by 481.8%; After inoculation ofA21-4, SOD, POD and PAL activities were all significantly increased up to 44.7%, 64.2% and 77.0% in the pepper roots, and 27.9%, 134.9% and 87.0% in pepper leaves respectively. Meanwhile soaking pepper root withA21-4 suspension induced its resistance to P. capsici.