Zhu Yongqi, Lv Xin, Li Tiansheng, Zhong Mingtao, Song Jianghui, Wang Haijiang, Cui Jing
College of Agriculture, Shihezi University, Shihezi, Xinjiang, China.
Front Plant Sci. 2022 Nov 15;13:1051935. doi: 10.3389/fpls.2022.1051935. eCollection 2022.
Cotton straw biochar (biochar) and compound biofertilizer (biofertilizer) have attracted wide attentions in the remediation of heavy metal-contaminated soils in recent years. However, few studies have explored the metabolomics of lateral roots of Cd-stressed cotton to determine the mechanism of biochar and biofertilizer alleviating Cd stress.
In this pot experiment, biochar and biofertilizer were applied to the soils with different Cd contamination levels (1, 2, and 4 mg kg). Then, the responses of cotton root morphology, vitality, Cd content, and antioxidant enzyme activities were analyzed, and the mechanism of biochar and biofertilizer alleviating Cd stress was determined by metabolomic analysis.
The results showed that exogenous Cd addition decreased the SOD and POD activities in cotton taproot and lateral root. Besides, with the increase of soil Cd content, the maximum Cd content in taproot (0.0250 mg kg) and lateral root (0.0288 mg kg) increased by 89.11% and 33.95%, respectively compared with those in the control ( 0.05). After the application of biochar and biofertilizer, the SOD and POD activities in cotton taproot and lateral root increased. The Cd content of cotton taproot in biochar and biofertilizer treatments decreased by 16.36% and 19.73%, respectively, and that of lateral root decreased by 13.99% and 16.68%, respectively. The metabolomic analysis results showed that the application of biochar and biofertilizer could improve the resistance of cotton root to Cd stress through regulating the pathways of ABC transporters and phenylalanine metabolism.
Therefore, the application of biochar and biofertilizer could improve cotton resistance to Cd stress by increasing antioxidant enzyme activities, regulating root metabolites (phenols and amino acids), and reducing Cd content, thus promoting cotton root growth.
近年来，棉秸秆生物炭（生物炭）和复合生物肥料（生物肥料）在重金属污染土壤修复方面备受关注。然而，很少有研究探索镉胁迫下棉花侧根的代谢组学，以确定生物炭和生物肥料缓解镉胁迫的机制。
在本盆栽试验中，将生物炭和生物肥料施用于不同镉污染水平（1、2和4 mg/kg）的土壤中。然后，分析棉花根系形态、活力、镉含量和抗氧化酶活性的响应，并通过代谢组学分析确定生物炭和生物肥料缓解镉胁迫的机制。
结果表明，外源添加镉降低了棉花主根和侧根中的超氧化物歧化酶（SOD）和过氧化物酶（POD）活性。此外，随着土壤镉含量的增加，主根（0.0250 mg/kg）和侧根（0.0288 mg/kg）中的最大镉含量与对照（0.05）相比分别增加了89.11%和33.95%。施用生物炭和生物肥料后，棉花主根和侧根中的SOD和POD活性增加。生物炭和生物肥料处理下棉花主根的镉含量分别降低了16.36%和19.73%，侧根的镉含量分别降低了13.99%和16.68%。代谢组学分析结果表明，生物炭和生物肥料的施用可通过调节ABC转运蛋白和苯丙氨酸代谢途径提高棉花根系对镉胁迫的抗性。
因此，生物炭和生物肥料的施用可通过提高抗氧化酶活性、调节根系代谢物（酚类和氨基酸）以及降低镉含量来提高棉花对镉胁迫的抗性，从而促进棉花根系生长。
