水分胁迫对温室滴灌葡萄根际土壤微生物碳源代谢活性的影响

【目的】探究干旱半干旱地区温室葡萄根际土壤微生物碳源代谢对不同滴灌水平的响应机制。【方法】采用单因素完全随机试验,运用Biolog技术分析了土壤微生物碳源代谢活性在不同水分处理水平(中度胁迫(W1)、轻度胁迫(W2)、充分供水(CK))下的变化特征。【结果】设施葡萄根际土壤中的单糖糖苷聚合糖类、氨基酸类、醇类、酸类等碳源利用程度较高,代表碳源有葡萄糖-1-磷酸盐、D-纤维二糖、甘氨酰-L-谷氨酸、I-赤藻糖醇、4-羟基苯甲酸、r-羟基丁酸;2种胁迫水平均能提升土壤微生物碳源代谢活性,胁迫初期W2处理土壤微生物碳源利用能力最高,中、后期W1处理碳源利用能力最高;轻度胁迫条件下总产和单果平均质量分别提高11.95%、2.62%,中度胁迫则减产。【结论】水分胁迫可以提高温室葡萄根际土壤微生物活性,强化其总体碳源代谢强度,胁迫初期W2处理代谢最强,中、后期W1处理最强。

The Effect of Water Stress on Carbon Metabolism in the Rhizospheric Microbiome of Greenhouse Grape

【Objective】Microbiome in the rhizosphere is associated with plant species and mediated by soil moisture.It plays an essential role in modulating biogeochemical reactions and nutrient and carbon cycles. The objective of this paper is to elucidate how carbon metabolism in microbes in the rhizosphere of grape responds to change in soil water content induced by drip irrigation.【Method】The experiment was conducted in a greenhouse in a region with semi-arid climate. The grape was drip-irrigated with the dripping rate varying to create a mild to moderate water stress to the crop; sufficient irrigation was taken as the control. In each treatment, we analyzed the metabolism of different carbon sources in the rhizospheric microbiome.【Result】Microbial utilization of monosaccharides,glycosides, polymerized sugars, amino acids, alcohols and acids was relatively high. The representative carbon sources were glucose-1-phosphate and D-cellobiose, Glycyl-L-glutamic acid, I-erythritol, 4-hydroxybenzoic acid,r-hydroxybutyric acid. Water stress increased the metabolization of all carbon sources. Carbon metabolization was the highest at early stage under mild water stress, while under moderate water stress, carbon utilization peaked in the middle and late stages of the treatment. Imposing a mild water stress increased total yield and average weight of single fruit by 11.95% and 2.62%, respectively, compared to the CK. In contrast, occurrence of moderate water stress led to a reduction in fruit yield.【Conclusion】Water stress increased microbial activity and boosted carbon metabolization in rhizospheric microbiome of the grape. Imposing a mild water stress affected the metabolic activity most strongly at the initial stage of the treatment, while a moderate water stress led to a surge in carbon metabolization in the middle and late stages of the treatment.