Phytopathology. 2003 Apr;93(4):443-50. doi: 10.1094/PHYTO.2003.93.4.443.
ABSTRACT Sclerotial germination of three isolates each of Sclerotinia minor and S. sclerotiorum was compared under various soil moisture and temperature combinations in soils from Huron and Salinas, CA. Sclerotia from each isolate in soil disks equilibrated at 0, -0.03, -0.07, -0.1, -0.15, and -0.3 MPa were transferred into petri plates and incubated at 5, 10, 15, 20, 25, and 30 degrees C. Types and levels of germination in the two species were recorded. Petri plates in which apothecia were observed were transferred into a growth chamber at 15 degrees C with a 12-h light-dark regime. All retrievable sclerotia were recovered 3 months later and tested for viability. Soil type did not affect either the type or level of germination of sclerotia. Mycelial germination was the predominant mode in sclerotia of S. minor, and it occurred between -0.03 and -0.3 MPa and 5 and 25 degrees C, with an optimum at -0.1 MPa and 15 degrees C. No germination occurred at 30 degrees C or 0 MPa. Soil temperature, moisture, or soil type did not affect the viability of sclerotia of either species. Carpogenic germination of S. sclerotiorum sclerotia, measured as the number of sclerotia producing stipes and apothecia, was the predominant mode that was affected significantly by soil moisture and temperature. Myceliogenic germination in this species under the experimental conditions was infrequent. The optimum conditions for carpogenic germination were 15 degrees C and -0.03 or -0.07 MPa. To study the effect of sclerotial size on carpogenic germination in both S. minor and S. sclerotiorum, sclerotia of three distinct size classes for each species were placed in soil disks equilibrated at -0.03 MPa and incubated at 15 degrees C. After 6 weeks, number of stipes and apothecia produced by sclerotia were counted. Solitary S. minor sclerotia did not form apothecia, but aggregates of attached sclerotia readily formed apothecia. The number of stipes produced by both S. minor and S. sclerotiorum was highly correlated with sclerotial size. These results suggest there is a threshold of sclerotial size below which apothecia are not produced, and explains, in part, why production of apothecia in S. minor seldom occurs in nature.
摘要 在胡伦和萨利纳斯的土壤中，比较了每个小核盘菌和核盘菌三个分离株的种核在不同土壤水分和温度组合下的萌发情况。将每个分离株的种核从平衡在 0、-0.03、-0.07、-0.1、-0.15 和-0.3 MPa 的土壤圆盘转移到培养皿中，并在 5、10、15、20、25 和 30°C 下孵育。记录了两种真菌的萌发类型和水平。观察到子囊壳的培养皿被转移到 15°C 的生长室中，光照-黑暗周期为 12 小时。3 个月后回收所有可回收的种核，并检测其活力。土壤类型既不影响种核的萌发类型，也不影响种核的萌发水平。在小核盘菌的种核中，菌丝体萌发是主要的萌发模式，发生在-0.03 至-0.3 MPa 和 5 至 25°C 之间，最适条件为-0.1 MPa 和 15°C。30°C 或 0 MPa 时不发生萌发。土壤温度、水分或土壤类型均不影响两种真菌种核的活力。核盘菌种核的产孢萌发，以产生梗和子囊壳的种核数量来衡量，是受土壤水分和温度显著影响的主要模式。在实验条件下，该物种的菌丝体萌发很少见。产孢萌发的最佳条件是 15°C 和-0.03 或-0.07 MPa。为了研究种核大小对小核盘菌和核盘菌产孢萌发的影响，将每个物种的三种不同大小的种核分别放置在平衡在-0.03 MPa 的土壤圆盘上，在 15°C 下孵育。6 周后，统计产生的梗和子囊壳数量。单独的小核盘菌种核不形成子囊壳，但附着的种核聚集体容易形成子囊壳。小核盘菌和核盘菌产生的梗数量与种核大小高度相关。这些结果表明，种核大小存在一个阈值，低于该阈值就不会产生子囊壳，这部分解释了为什么小核盘菌在自然界中很少产生子囊壳。
