| Sugarcane planting has been plagued by drought disasters all year round,resulting in difficulties in planting and low yield.The continuous and stable development of China's sugar industry has caused a great impact.Therefore,how to break through and solve the problem of sugarcane drought resistance is especially severe.In this experiment,Zhongzhe No.1 and Zhongzhe No.6 were subjected to different degrees of drought exercise by pot cultivation.A complete analysis of root morphology was performed.At the same time,the microbial community and metabolome in the soil environment were analyzed and compared in order to find the most suitable way and degree of drought exercise for sugarcane planting and drought resistance in the future.The main results of this study are as follows:1.The root system configuration: after drought exercise,the root length increased obviously and the number of lateral roots decreased.At 0-20 cm,the total root length and total area of the drought-exercised sugarcane roots decreased,while at 40-60 cm layer,the total root length and total area of the drought-exercised sugarcane roots increased.In the 20-40 cm section,the total root length and total surface area of sugarcane roots tempered by mild stress increased,and they still maintained their increasing advantages in the 40-60 cm section.Drought exercise induced the content of abscisic acid and auxin to increase,while cytokinin to decrease obviously.With the increase of drought degree,abscisic acid and auxin to decrease gradually,and cytokinin to increase gradually.2.Soil enzyme activity:the activity of catalase in rhizosphere soil decreased with the deepening of drought,while the contents of urease and acid phosphatase increased under mild drought stress,and then decreased with the deepening of drought.The activities of urease and acid phosphatase after mild treatment were increased by 3.47% and 2.55%,respectively,and by 2.98% and2.05%,respectively,compared with those of normal CK.3.Nutrient:compared with normal watering,soil carbon,nitrogen and phosphorus contents decreased after different degrees of drought exercise,but mild drought exercise had little effect on nutrient content of ZZ1,and nitrogen content increased by 1.34% instead of decreasing.Although the contents of carbon and phosphorus were decreased,compared with normal watering CK,mild drought exercise had the least effect on it,which decreased by 10.02% and6.98%,moderate drought exercise decreased by 24.59% and 22.82%,and severe drought exercise decreased by 30.46% and 12.61%,respectively.4.Soil bacteria:with the increase of stress degree,the main flora had changed greatly,and the difference between the flora and CK gradually increased.Among them,Actinobacteria and Proteobacteria showed an increase,while Bacteroidetes showed a decrease.These results indicate that when sugarcane is subjected to drought stress,the rhizosphere soil microorganisms will be changed by increasing the flora of growthpromoting bacteria such as actinomyces and increasing the activities of rhizosphere microorganisms,so as to provide more nutrients to the soil for the root system to absorb in response to drought.Moreover,with the increase of drought degree,the change of such flora will be more obvious.5.Soil metabolome:The changes of different substances were mainly concentrated in the increase of acids and sugars,and the decrease of alcohols and lipids.Significant upregulation of beta-alanine metabolism and Pantothenate and Co A biosynthesis was associated with Arginine and proline metabolism Metabolism and Pyrimidine metabolism were significantly downregulated.The results indicated the root changes of soil metabolome. |
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