番茄连作与轮作土壤生物学特性及细菌群落结构的比较

Comparison of Soil Microbial Properties and Bacterial Community Structure in Continuous Cropping and Rotation Fields of Tomatoes

随着全国番茄(Lycopersicon esculentum)的规模化生产以及形成相对固定的生产区域,番茄连作障碍现象逐年严重。文章针对番茄连作、轮作土壤的生物学特性及细菌群落结构展开了分析,旨在揭示连作与轮作土壤中生物学特性及细菌群落结构的变化规律,为保障番茄产业的可持续发展提供技术支撑。试验分别设置番茄-番茄、番茄-茄子(Solanium melongena)、番茄-辣椒(Capsicum annuum)连作和番茄-黄瓜(Cucumis sativus L.)、番茄-白菜(Brassica campestris L.)、番茄-菜豆(Phaseolus vulgaris)轮作共6个处理。采用聚合酶链式反应-变性梯度凝胶电泳(PCR-DGGE)以及稀释平板法等现代和传统分析技术,比较分析了连作和轮作不同蔬菜作物对土壤生物学性状和细菌群落结构的影响。结果表明:番茄连作导致土壤可培养细菌、放线菌数量显著降低,真菌数量显著增加,微生物群落由细菌型向真菌型转变;同时连作还导致土壤中指示土壤肥力的微生物生物量碳、氮和涉及碳、氮、磷循环相关酶活性显著降低;此外,番茄连作导致土壤细菌多样性指数(H)、均匀度指数(EH)和丰富度指数(S)下降,番茄连作土壤中主要以不可培养细菌(Uncultured bacterium)为优势种属。相比之下,番茄轮作不仅能显著增加微生物数量,提高土壤微生物生物量碳、氮和酶活性,而且轮作土壤中除了维持较高的细菌多样性之外,还出现假单胞杆菌属(Pseudomonas sp.)等促生细菌种属。表明番茄轮作有利于提高土壤肥力和保持土壤健康。其中,番茄轮作黄瓜、白菜和菜豆3种不同科属蔬菜作物中,以轮作菜豆更有利于提高土壤肥力和保持土壤健康。

At present, with the development of tomato industry and regularization of produce in China, continuous cropping obstacle problem of tomato is more severe. To ensure the implementation of sustainable development of tomato industry, this paper presents a detail analysis of the changes of soil biological properties and bacterial community structure between continuous and rotation cropping of tomatoes. In this experiment, the continuous and rotation cropping models, such as tomato-tomato, tomato-eggplant, tomato-pepper, tomato-cucumber, tomato-Chines cabbage, tomato-kidney beans were randomly divided into 6 disposals, with 3 repetitions in each disposal. Using thetraditional and modern analyzing techniques, such as dilution-plate method and PCR-DGGE, etc., the soil microbial properties and bacterial community structure in soils between rotation and continuous cropping fields of tomatoes were analyzed. Results showed that the numbers of cultivable bacteria and actinomycetes in the continuous cropping soil were significantly decreased compare to those in rotation fields and the numbers of cultivable fungi were significantly increased. Moreover, the activities of soil enzymes that are involved in C, N and P recycling (β-Glucosidase, phosphatase and protease) and biomass C, N in the continuous cropping soil were significantly lower than those in rotation fields. Additionally, in terms of bacterial diversity index, both the richness/evenness in the continuous cropping fields was inferior to the rotation soils, respectively. Meanwhile, in the tomato continuous cropping field, the uncultured bacterium was the dominant species. By contrast, except of the higher bacterial diversity, richness and evenness indexes, some of the plant growth promoting bacteria (PGPB), such as Pseudomonas, etc., was also detected in the rotation fields. All the findings indicate that rotation cultivation is more helpful for improving soil fertility and maintaining soil health. Finally, kidney bean was the best rotation crop for tomatoes among the three rotation crops such as cucumbers, Chinese cabbage and kidney beans.