黄瓜霜霉病菌侵染黄瓜叶片过程中内部组织变化的研究

Changes in cucumber leaf internal tissues during the infection of cucumber downy mildew

以黄瓜(Cucumis sativus)感病品种‘长春蜜刺’为试验材料,利用X射线三维显微镜成像技术观察霜霉病菌侵染过程中叶片内部组织的变化,测量气孔导度、叶片温差和孔隙结构从而确定黄瓜霜霉病的潜育期,结果表明:温度23°C,湿度100%,结露时间8 h,霜霉病菌侵染68~74 h后,接菌一侧的叶片气孔导度显著大于未接菌侧,且叶片出现温度差异,确定叶片处于潜育期;在X射线三维显微镜观察下发现,菌丝在接菌后的68~70 h侵染至叶片厚度的75%(第60/80层)并造成孔隙结构的降低,此时叶片进入潜育期。利用X射线三维显微镜不仅可以观察叶片整体的结构,还能将内部结构进行分割,精确定位病菌侵染的时间段、侵染位置以及潜育期的时间,可为病菌侵染叶片后生理变化的研究提供理论依据。

In order to determine the downy mildew incubation period in cucumber(Cucumis sativus)‘Changchun Honey Thorn’,we observed the changes in leaf internal tissues by X-ray microscopy imaging technique,and determined the stomatal conductance and leaf temperature differences.The results show that after infection of downy mildew for 68~74 h,stomatal conductance and leaf temperature were significantly increased compare to the uninoculated side under the condition of 23°C,100%humidity,8 h dew time,which determined the incubation period.Under the X-ray microscope,the hyphae infected 75%leaf thickness(60/80 layer)which caused a decrease in pore structure at 68~70 h,and leaves entered the incubation period.Through the X-ray microscopy,not only could we observe the blade as a whole,but also the segmental internal structure,from which we can accurately locate the infected period,infected position and incubation period.The study would provide theoretical basis for the research of physiological changes of leaves infected by pathogens.