7株放线菌在辣椒根部定殖及对辣椒叶片PAL与PPO活性的影响

Root Colonization and Effects of Seven Strains of Actinomycetes on Leaf PAL and PPO Activities of Capsicum

采用盆栽接种试验、平皿涂抹法测数及常规酶活测定法研究了7株拮抗性放线菌在辣椒根部的定殖能力及接种24 d对辣椒叶片苯丙氨酸解氨酶(PAL)与多酚氧化酶活性(PPO)的诱导效应。结果表明:(1)供试7株放线菌单独接种均不能在辣椒根内定殖,但与辣椒疫霉P3混合接种时有5株可定殖;供试放线菌在辣椒根部的定殖能力与其体外平皿试验中产生的的拮抗圈大小基本无关;可定殖放线菌的定殖密度随时间延长而降低,至40 d时均无活菌检出。(2)在放线菌单接处理中,5株菌接种后可诱导辣椒叶片PAL活性提高,全部供试菌均能诱导PPO活性提高,其中可使两种酶同步提高的有5株菌;在放线菌+P3混接处理中,有6株接种后可诱导PAL活性提高,5株菌能诱导PPO活性提高,其中可使两种酶同步提高的有4株菌;在接入放线菌时同时混接辣椒疫霉,能增强2株供试放线菌对辣椒叶片PAL活性及6株供试放线菌对辣椒叶片PPO活性的诱导作用;供试放线菌的定殖能力与辣椒叶片PAL及PPO活性变化无明显规律性关系。

Capsicum was pot planted and inoculated with seven strains of actinomycetes to study the rootcolonizing capabilities and inducing effects of the strains on PAl. and PPO activities in the leaves of capsicum twenty-four days after its inoculation by Petri dish smearing method and conventional enzymatic activity testing method. The results revealed that （1） the seven strains could not individually colonize capsicum roots, but five of them could colonize the roots while they were mixed with P. capsici （P3 in short） in the inoculation; the colonizing capabilities of the test strains of actinomycetes did not relate to the sizes of the inhibitory zones they formed in the Petri dishes ; the root-colonizing strains of actinomycetes declined in their colonization densities with time and no alive actinomycetes were detected up to forty days after the inoculation. （2） In the treatments with the strains individually inoculated, five strains resulted in an,increased PAL activity in the leaves of capsicum , all the test strains could increase the PPO activity, and five strains could synchronously increase the activities of the two enzymes; in the treatments with the combined inoculation with actinomycetes and Pa, five strains could induce the PAl. activity in the leaves of capsicum to increase , five strains could induce the PPO activity to increase and four strains could induce the PPO and PAl. activities to synchronously increase ; the synchronous inoculations with the actinomycete strains and P3 could make two strains increase the PAl. activity in the leaves of capsicum , five strains increase the PPO activities in the leaves of capsicum; no regular relations between the colonizing capabilities of the test strains and the PAl. and PPO activities was found.