不同林龄木麻黄林地特有细菌代谢产物及其化感潜力

The special bacterial metabolites and allelopathic potentials in Casuarina equisetifolia woodland of different stand ages

为揭示土壤微生物代谢产物的组成及其在植物化感作用中的影响机制,采用GC-MS比较分析不同林龄木麻黄林地特有细菌与木麻黄土壤、根、凋落物的代谢产物,并研究木麻黄林地特有细菌发酵液对3种乡土树种青皮、红厚壳和杨叶肖槿种子萌发的影响.结果表明:木麻黄林地特有细菌代谢产物主要为酸、酯、烷、醛、酮、酰胺、酚类、醚类、吡喃、吡啶等有机化合物.以甲醇为萃取剂共萃取出60余种物质,以正己烷为萃取剂共萃取出20余种物质.与木麻黄土壤、根、凋落物浸提液GC-MS结果比较,发现2,4-二叔丁基苯酚、硬脂酸甲酯、1,2,3,4-丁四醇、甘油醚和苯并吡喃5种相同物质,及仅在特有细菌中存在的4-甲基-6-叔丁基苯酚.该物质与土壤浸提液中2,4-二叔丁基苯酚的结构类似,二者可通过烷基取代发生转化.表明木麻黄林地土壤细菌产生的代谢产物可在土壤中积累,或经过转化后进入土壤.木麻黄林地特有细菌发酵液对青皮、红厚壳和杨叶肖槿种子的生物测定结果表明,其发酵液对三种植物种子萌发均具有抑制作用,对青皮种子的抑制作用最为强烈,最低发芽率为25.3%,最强化感效应指数为-0.43.说明土壤细菌代谢产物参与了木麻黄的化感作用.

Exploring the composition of the soil microorganism metabolites can reveal its effects on plant allelopathy mechanism.We used GC-MS compared and analyzed the bacterial metabolites of special bacteria,soil,root and litter metabolites in Casuarina equisetifolia woodland of different stand ages,and examined the allelopathic potential of these bacterial metabolites on germination of 3 native tree species（Vatica mangachapoi,Calophyllum inophyllum and Thespesia populnea）.The bacterial metabolites were found to be mainly acid,ester,alkane,aldehyde,ketone,amide,phenols,ethers,pyran,pyridine and some other kinds of organic compounds.Using methanol as the extracting agent we extracted more than 60 kinds of substances;using hexane as the extracting agent we extracted more than 20 kinds of substances.We found besides the unique materials,5 materials were present in common in the bacterial metabolites,soil,roots and litter extracts of C.equisetifolia woodland of different stand ages,including Phenol,2,4-bis（1,1-dimethylethyl）-,Octadecanoic acid,methyl ester,1,2,3,4-Butanetetrol,Diglycerol and Chromene.Phenol,6-（1,1-dimethylethyl）-4-methyl was found in specific bacteria,which was similar in structure with the soil metabolite 2,4-bis（1,1-dimethylethyl）-.The metabolites of the bacteria in C.equisetifolia of different stand ages may accumulate in the soil,or accumulate after transformation into the soil.The fermented liquid showed inhibition on seed germination of the 3 native tree species,the strongest inhibitory effect being on V.mangachapoi seeds,with the lowest germination rate of 25.3%,and the strongest allelopathic effect index of-0.43.It shows that soil bacteria metabolites involved in the casuarinas allelopathy.