Phytopathology. 1999 Dec;89(12):1127-30. doi: 10.1094/PHYTO.1999.89.12.1127.
ABSTRACT Infection of cranberry flowers by conidia of Monilinia oxycocci, the cottonball pathogen, was investigated using a squash-mount histological method. Conidia germinated on anthers, nectaries, petals, and stigmata, but not styles. The stigma was the only flower part penetrated by the fungus, but no specialized infection structures were noted. Both fungal and pollen germ tubes grew through the stylar canal and made contact with ovules and nucellar tissue by 72 h after inoculation and pollination. Cottonball incidence was greatest when stigmata were inoculated; the low level of cottonball that resulted from inoculation of other flower parts and in noninoculated flowers was attributed to contamination of stigmata. In greenhouse tests, cottonball incidence was 25, 28, 31, and 38% for cvs. Searles, Pilgrim, Ben Lear, and Stevens, respectively, and was greater for M. oxycocci isolate 593 than isolate 591. We conclude that the stigma is the sole floral infection court for conidia of M. oxycocci and that the most popular cranberry cultivars in Wisconsin do not differ in inherent resistance to cottonball. The relevance of these findings to the long-term management of cottonball is discussed.
摘要 使用压片组织学方法研究了蔓越橘花被棒孢霉菌（Monilinia oxycocci）分生孢子的感染情况，棉花球病原体。分生孢子在花药、蜜腺、花瓣和柱头萌发，但不在花柱上萌发。柱头是真菌唯一穿透的花朵部分，但没有注意到专门的感染结构。真菌和花粉管在接种和授粉后 72 小时通过花柱管生长，并与胚珠和珠心组织接触。当柱头接种时，棉花球的发病率最高；从其他花朵部分接种和未接种花朵中产生的棉花球的低发病率归因于柱头的污染。在温室试验中，Searles、Pilgrim、Ben Lear 和 Stevens 品种的棉花球发病率分别为 25%、28%、31%和 38%，而 593 号分离物的发病率高于 591 号分离物。我们得出的结论是，柱头是棒孢霉菌分生孢子的唯一花部感染法庭，威斯康星州最受欢迎的蔓越橘品种在对棉花球的固有抗性方面没有差异。讨论了这些发现对棉花球长期管理的相关性。
