不同施肥处理对茶树根际细菌多样性的影响

采用变性梯度凝胶电泳(denaturing gradient gel electrophoresis, DGGE)方法测定茶树根际和根围土细菌群落丰富度，结合土壤pH和C/N分析影响因子，并通过16S rRNA基因序列分析特异菌株的系统发育地位，最后利用比色法对茶树根系生长素(IAA)含量进行定量检测，探讨不同施肥处理下茶树根际和根围土细菌的群落的变化以及对茶树根系生长的促进影响。结果表明：有机肥能明显增加土壤C/N，C/N与细菌丰富度正相关，相关系数(r)为0.93(P＜0.05)；有机肥与化肥(7:3)的处理，根际细菌多样性最高，有机肥与化肥(95:5)的处理，根围土中的细菌多样性最高；化肥和有机肥会影响特异菌种的定殖效率；茶树根生长素(IAA)定量测定发现，根际细菌多样性最高的处理，根系IAA的含量也最高。研究表明有机肥施用能提高节土壤C/N和微生物区系多样性但对土壤pH的提升有限；C/N与茶树根际细菌群落多样性正相关。

Effect of Fertilizer on Tea Plant Rhizosphere Bacteria Diversity

Denaturing gradient gel-electrophoresis (DGGE) method was employed for the determination of tea plant rhizosphere bacteria community diversity with soil pH and C/N to investigate the effect of different fertilization treatments on the rhizosphere bacteria community. More detailed analysis of 16S rRNA gene sequences to determine the phylogenetic position of specific strains. In addition, root auxin (IAA) quantity was detected by colorimetry. Results showed organic fertilizer could significantly increase soil C/N, which was positively correlated to bacteria community, for the correlation coefficient (R) was 0.93 (P<0.05). Among different treatments, bacteria diversity was the highest in the organic and chemical fertilizer (7:3) treatment (rhizosphere) and (95:5) treatment (soil) respectively. Bacteria 16SrRNA band gene sequences showed chemical fertilizer or organic fertilizer would affect the efficiency of specific bacterial colonization. The results also showed the highest bacteria diversity treatment also contained the highest content of IAA in tea root. The conclusion is organic fertilizer can elevate soil C/N and microbial community diversity and bacterial diversity positively has relationship to soil C/N.