甘蔗间作玉米对甘蔗根际微生物代谢功能多样性的影响

Effects of sugarcane and maize intercropping on sugarcane rhizosphere microbe metabolic function diversity

  • 摘要: 为探讨甘蔗间作玉米种植对甘蔗根际土壤微生物群落功能多样性的影响, 在云南元江和陇川甘蔗种植区设置甘蔗间作玉米和单作甘蔗田间小区试验, 采用Biolog技术研究了甘蔗间作玉米对甘蔗根际微生物代谢功能的影响。结果表明: 陇川试验点甘蔗间作玉米田土壤微生物代谢功能多样性指数Shannon多样性指数、Simpson指数、McIntosh指数、Shannon均匀度指数和McIntosh均匀度指数分别比甘蔗单作田提高7.08%、11.25%、63.16%、1.31%和2.26%; 元江试验点, 甘蔗间作玉米田土壤微生物代谢功能多样性指数Shannon多样性指数、Simpson指数、McIntosh指数、Shannon均匀度指数和McIntosh均匀度指数分别比甘蔗单作田提高10.58%、48.40%、43.42%、0.20%和1.65%。由此表明甘蔗间作玉米种植提高了甘蔗根际土壤微生物的多样性。甘蔗间作玉米种植提高了甘蔗根际微生物对碳源的利用率, 且元江甘蔗根际土壤微生物对碳源的利用效率低于陇川。与单作甘蔗相比, 元江试验点间作甘蔗根际碳水化合物类、氨基酸类、多聚物类、胺类、羧酸类和酚酸类利用率分别提高141.71%、50.53%、62.38%、92.82%、43.21%?和6.30%, 陇川试验点分别提高42.90%、51.50%、33.30%、42.64%、16.72%和24.47%。其中, 两个试验区间作田甘蔗根际土壤微生物对碳源D-纤维二糖、D,L-a-甘油、D-半乳糖-γ-内酯、L-丝氨酸、甘氨酰-L-谷氨酸和2-羟苯甲酸的利用率比单作显著提高100%以上。通过主成分分析, 发现甘蔗与玉米间作改变了甘蔗根际微生物的群落组成及其代谢功能, 且碳水化合物类、羧酸类和氨基酸这3类碳源是区分甘蔗单作和间作处理间差异的敏感碳源。陇川试验点, 对土壤微生物代谢功能影响较大的碳源主要包括2种多聚化合物、6种碳水化合物、2种羧酸类化合物、4种氨基酸和1种酚酸; 元江试验点, 对土壤微生物代谢功能影响较大的碳源主要包括1种多聚化合物、5种碳水化合物、3种羧酸类化合物、4种氨基酸和2种胺类化合物。综上所述, 宿根甘蔗间作玉米提高了甘蔗根际微生物群落的多样性, 增加了根际微生物的活性, 改变了微生物群落的代谢功能。研究结果可为作物间作对土壤微生物多样性分析及增产机理研究提供新的思路和理论基础。

     

    Abstract: Sugarcane-maize intercropping is an important planting pattern in sugarcane production area, which is in favor of sugarcane production benefit and land use efficiency increases, and pesticide control of sugarcane. However, the effects of sugarcane and maize intercropping on sugarcane rhizosphere microbe community have less been reported. In this study, a plot experiment was carried out in sugarcane fields in Yuanjiang and Longchuan Counties of Yunnan Province to investigate the microbe activities, metabolic function diversity and carbon sources utilization by using Biolog techniques. The results showed that compared with monocultured sugarcane at Longchuan County experimental site, Shannon index, Simpson index, McIntosh index and evenness index of Shannon and McIntosh of microbial communities in rhizosphere soils of intercropped sugarcane increased by 7.08%, 11.25%, 63.16%, 1.31% and 2.26%, respectively. Then, compared with sugarcane monoculture in Yuanjiang County, the above diversity indices increased by 10.58%, 48.40%, 43.42%, 0.20%, and 1.65%, respectively, in intercropped sugarcane treatment. This suggested that intercropping increased the metabolic function diversity of rhizosphere soil microbes. Although the utilization of carbon resources increased in intercropping systems, it was lower at Yuanjiang experimental site than that at Longchuan experimental site. Compared with monoculture, the utilization of carbohydrate, amino acids, polymeric substances, amines, carboxylic acids and phenolic acids increased by 141.71%, 50.53%, 62.38%, 92.82%, 43.21% and 6.30%, respectively, at Yuanjiang experimental site. Correspondingly, the variables increased, respectively by 42.90%, 51.50%, 33.30%, 42.64%, 16.72% and 24.47% at Longchuan experimental site. Moreover, the utilization of D-cellobiose, D,L-α-glycerol phosphate, D-galactonic acid-γ-lactone, L-serine, Glycyl-L-Glutamine and 2-Hydroxy benzoic acid increased by over 100% at both of Yuanjiang and Longchuan experimental sites. The results of principal component analysis (PCA) suggested that intercropping changed rhizosphere soil microbial community composition and metabolic function. Three carbon resources (including carbohydrate, carboxylic acids and amino acids) were the most sensitive carbon resources utilized by soil microorganisms in sugarcane rhizosphere soils. The carbon resources with high effect on microbial community composition and metabolic function at Longchuan experimental site were 2 kinds of polymeric substances, 6 kinds of carbohydrates, 2 kinds of carboxylic acids, 4 kinds of amino acids and 1 kind of phenolic acid. There were 15 kinds of carbon resources (including 1 kind of polymeric substances, 5 kinds of carbohydrates, 3 kinds of carboxylic acids, 4 kinds of amino acids and 2 kinds of amines) at Yuanjiang experimental site. These carbon resources had significant effect on microbial community composition and metabolic function. In conclusion, intercropping of maize and sugarcane increased microbial community diversity, activation and metabolic function of rhizosphere soil.

     

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