不同因素影响下棉田土壤中大丽轮枝菌微菌核的数量特征

【目的】 土壤中大丽轮枝菌的微菌核是棉花黄萎病发生的关键因子,研究外界因素对土壤中微菌核数量的影响特征,为棉花黄萎病的防治提供参考意义。【方法】 利用选择性分离培养与荧光定量PCR技术,检测采自新疆棉花黄萎病田内不同处理组土壤中的微菌核,并结合室内盆栽试验进行验证。【结果】 大丽轮枝菌微菌核在棉田土壤中呈聚集分布,不同抗病性棉花品种根围微菌核的数量无明显差异。花铃期时'新陆中66号根围微菌核的数量显著高于新稻11号,至吐絮期时新稻11号根围微菌核数量显著增加,与新陆中66号根围相比已无显著差异。耐病品种中植棉2号以及中植棉2号＋新稻11号混种处理土壤中微菌核数量与感病品种军棉1号及军棉1号+新稻11号混种处理均无显著差异。水淹20~30 d时土壤中微菌核的数量显著上升,至60 d土壤中微菌核数量略下降,至150 d时微菌核数量升至最高,是初期微菌核数量的5倍;种稻处理土壤中微菌核的消长动态与对照一致,至150 d时微菌核数量是初期的8倍。【结论】 大丽轮枝菌微菌核在土壤中聚集分布,其数量与棉花品种的抗病性无明显相关,大田种植旱稻前期能延缓微菌核的增长。盆栽水淹能够显著促进土壤中微菌核数量的增长,种稻未能抑制甚至促进了土壤中微菌核数量的增长。

Quantitative Characteristics of Microsclerotia of Verticillium dahliae in Cotton Field Soil under Different Factors

【Objective】 Microsclerotia of Verticillium dahliae in soil is the basis of cotton Verticillium wilt. This project aims to clarify the influence of external factors on microsclerotia in soil and provide a solution for the prevention and control of the disease.【Method】 The microsclerotia in soils collected from cotton field with Verticillium wilt under different treatments were detected using selective isolation and culture technology, and verified by indoor pot experiment.【Result】 Microsclerotia were aggregated in the soil of cotton field. Its number in the cotton rhizosphere was not significantly correlated with its disease resistance. Comparing cotton with upland rice, at the flowering and boll-forming stages, the number of microsclerotia in the cotton rhizosphere was significantly higher than that in the rice rhizosphere. At the harvest stage, the number of microsclerotia in the rice rhizosphere increased significantly, but showed no significant difference with the number of microsclerotia in the cotton rhizosphere. Indoor pot experiment revealed no significant differences in the number of microsclerotia in the rhizosphere soil between disease-resistant varieties Zhongzhimian 2, Zhongzhimian 2 + rice treatment and susceptible variety Junmian 1, Junmian 1 + rice mixed treatment. Water flooding was performed for the soil. After 20-30 days of waterflooding, the number of microsclerotia in soil increased significantly, but decreased slightly at the 60th day. After 150 days, the number of microsclerotia increased to the highest level, which was five times as much as that in the initial stage. The dynamics of growth and decline of microsclerotia in soil under rice + waterflooding treatment were consistent with those in blank control, presenting a trend of rapid increase, then decrease and then increase. The number of microsclerotia at the 150th day was 8 times as much as that in the initial stage.【Conclusion】 Microsclerotia are aggregated in the soil of cotton field. The number of microsclerotia in the cotton rhizosphere is not significantly correlated with its disease resistance. Planting upland rice in field can delay the growth of microsclerotia in early stage. Water flooding significantly promotes the growth of microsclerotia in potted planting soil. Rice planting fails to inhibit or even fail to promote the growth of microsclerotia in soil.