Phytopathology. 1997 Feb;87(2):197-202. doi: 10.1094/PHYTO.1997.87.2.197.
ABSTRACT Factor(s) involved in soil suppressiveness to Thielaviopsis basicola when hairy vetch was used as a green manure were studied in a cotton production system. Soil suppressiveness was assessed in vitro at hairy vetch amendment levels of 0, 0.25, and 0.75% (wt/wt) by observing chlamydospores, using a nylon fabric technique. Chlamydospore germination in all soils was below 5%, and microscopic examination showed no germ tube lysis or visible propagule destruction. Viability (chlamydospore germination on T. basicola-carrot-etridiazol-nystatin [TB-CEN] medium) was reduced by 29% within 48 h after hairy vetch amendment. Viability also was reduced in atmospheres of amended soils, suggesting that the suppressiveness was due to a volatile factor. In a field study, chlamydospore viability in amended soils was reduced by 16%. T. basicola hyphal growth was more sensitive to ammonia than Rhizoctonia solani or Pythium ultimum, and chlamydospore mortality of T. basicola was 100% in petri dish atmospheres with 0.4 ppm of ammonia (50% lethal dose = 0.15 ppm). Soil atmospheric ammonia was 0.08 and 0.10 ppm for 0.25 and 0.75% amendment levels, respectively, both at 3 and 7 days after incorporation. In the field, 0.11 and 0.14 ppm of ammonia were detected in soil atmospheres 3 and 7 days after incorporation, respectively. The levels of ammonia detected were sufficient to account for the loss in T. basicola chlamydospore viability, indicating that ammonia is responsible for the suppressiveness observed.
摘要 本研究在棉花生产系统中，以毛叶苕子作为绿肥，探讨了其根系分泌物对层出镰刀菌的土壤抑病性相关因子。通过观察厚垣孢子，采用尼龙织物技术，在毛叶苕子添加水平为 0、0.25%和 0.75%（wt/wt）的条件下，在体外评估土壤的抑病性。所有土壤的厚垣孢子萌发率均低于 5%，显微镜检查显示没有孢子管裂解或可见的繁殖体破坏。在毛叶苕子添加后 48 小时内，厚垣孢子的活力（在层出镰刀菌-胡萝卜-乙二醛-制霉菌素[T.B-CEN]培养基上的厚垣孢子萌发）降低了 29%。添加土壤的大气中活力也降低了，这表明这种抑病性是由于挥发性因素造成的。在田间研究中，添加土壤中的厚垣孢子活力降低了 16%。与立枯丝核菌或腐霉相比，层出镰刀菌的菌丝生长对氨更为敏感，在 0.4 ppm 氨（50%致死剂量=0.15 ppm）的培养皿大气中，厚垣孢子的死亡率为 100%。添加水平分别为 0.25%和 0.75%时，在 3 天和 7 天后，土壤大气中的氨含量分别为 0.08 和 0.10 ppm。在田间，添加后 3 天和 7 天，土壤大气中的氨含量分别为 0.11 和 0.14 ppm。检测到的氨水平足以解释层出镰刀菌厚垣孢子活力的丧失，这表明氨是造成所观察到的抑制作用的原因。
