不同种植模式背景下栽植生姜对紫色土细菌多样性的影响

为了解栽植生姜对岷江下游紫色丘陵区不同种植模式背景下典型紫色土微生物多样性的影响,采用PCR-DGGE与DNA序列分析方法,研究了紫色丘陵区玉米+红薯间作、大豆单作、生姜连作、水稻-紫云英轮作等4种典型种植模式背景下栽植生姜前后土壤细菌多样性变化特征。PCR-DGGE分子指纹图谱结果表明,同一种植模式下栽种生姜前后DGGE条带数目、位置和亮度差异明显。栽种生姜均降低了各模式下土壤细菌群落丰富度和Shannon-Wiener指数,明显改变了土壤细菌群落结构,其中生姜连作模式背景下土壤细菌丰富度和Shannon-Wiener指数下降幅度最大,玉米+红薯间作模式下降幅度最小,但栽植生姜后4种种植模式之间土壤细菌群落结构相似度明显增加。DGGE特征条带的序列分析表明,栽植生姜后,土壤细菌中的部分绿弯菌门类群消失,部分硝化螺旋菌门类群仅在水稻-紫云英轮作模式中发现、玉米+红薯间作模式中出现了短波单胞菌门的细菌。这些结果为了解栽植生姜对土壤环境的影响以及生姜种植模式的优化提供了一定的科学依据。

Effects of ginger cropping on bacterial diversity in purple soils in different cropping background

Ginger cropping could regulate composition of soil microbial community, but its previous cropping might alleviate or aggregate the effect. To understand the effects of ginger cropping on soil microbial community as affected by its preceding cropping, variations of soil bacterial diversity were studied by analyzing PCR-DGGE fingerprints and DNA sequence in purple soil area of the Minjiang River. Four typical cropping modes (interplanting of corn + sweet potato, mono-cropping of soybean, continuous cropping of ginger, and rice-milk vetch rotation cropping) in this region were selected for the study. PCR-DGGE fingerprints clearly show that cultivation of ginger caused changes in number, position and brightness of DGGE bands, regardless of cropping background of the soil, e.g. reducing richness and Shannon-Wiener index of soil bacteria, and altering structure of the bacterial community. Among the four cropping patterns, the effects were the most significant in the one of continuous cropping of ginger, and the least in the one of interplanting of corn and sweet potato. However, cultivation of gingers made the soils under four different cropping patterns tend to be similar in structure of bacterial community. Sequencing of DGGE bands demonstrates that cultivation of ginger brought about disappearance of Chloroflexi group, and Nitrospira group as well, except for in the soil under the pattern of intercropping of rice-milk vetch, and appearance of bacteria of Brevundimonas in the soil under the pattern of interplanting of corn+sweet potato. The findings help understand the effects of ginger cultivation on soil environment, and provide some scientific basis for optimizing the mode of ginger cultivation.