ABSTRACT

Verticillium wilt (V-wilt) causes huge and irreparable losses to cotton worldwide every year. Potassium (K) is considered to be a critical nutrient for resistance to biotic and abiotic stresses. To verify the effect of K application on the establishment of an ecological-friendly soil microenvironment resistant to V-wilt, a two-year field experiment was conducted. Two cotton varieties (ND-601, resistive and JM-11, sensitive) with different resistance to V-wilt were used in this study, and five different K rates (0, 75, 150, 225, and 300 kg ha⁻¹ K₂O) were set for each variety in the field inoculated with Verticillium dahliae (V. dahliae). The results showed that different levels of K application had significant effect on the reduction of cotton V-wilt. K application increased the content of K and total phenolics in rhizosphere soil, but decreased the content of soluble sugar and alanine. Moreover, K application reduced the number of bacteria, fungi, and total microorganisms in rhizosphere soil, especially the number of V. dahliae. In conclusion, K application can create a good micro-ecological environment for the root system by changing the K status, root exudates, and microorganisms in rhizosphere soil, which are beneficial to reduce the symptoms of cotton V-wilt.

摘要

黄萎病（V-wilt）每年给全世界的棉花造成巨大的、无法弥补的损失。钾 (K) 被认为是抵抗生物和非生物胁迫的关键营养素。为验证施钾对建立抗青枯病的生态友好型土壤微环境的影响，进行了为期两年的田间试验。本研究使用了两种对 V 型枯萎病具有不同抗性的棉花品种（ND-601，抗性和 JM-11，敏感），以及五种不同的 K 率（0、75、150、225 和 300 kg ha ^-1 K大丽黄萎病菌_（V. dahliae）。结果表明，不同施钾量对棉花V型枯萎病的防治效果显着。施钾提高了根际土壤中钾和总酚的含量，但降低了可溶性糖和丙氨酸的含量。此外，钾肥施用减少了根际土壤中细菌、真菌和总微生物的数量，尤其是大丽花的数量。综上所述，施钾可以通过改变根际土壤中钾的状态、根系分泌物和微生物，为根系创造良好的微生态环境，有利于减轻棉花V型枯萎病的症状。