عنوان مقاله [English]
نویسندگان [English]چکیده [English]
The cultivars Green Mignonette and All year which are resistant and susceptible to Fusarium wilt, respectively were studied for histopathological aspect during the development of Fusarium oxysporum f. sp. lactucum. 15 days - old seedling was inoculated by root dip method in spore suspension of the pathogen with concentration about 5 X 106 spores/ml. Sampling was carried out at different times (3, 6, 10 and 20 days) after inoculation. After sectioning and holding of samples in fixative solutions and staining, preparations were studied by light microscope. The vascular system frequently exhibits a brown discoloration, vascular occlusion, tylose, and disintegration of the xylem parenchyma cells. After penetrating the young root tip of susceptible cultivar, the fungus progressed both inter and intracellulary throughout the cortex tissue and the vascular system. During this study, only vascular occlusion was observed in resistant cultivar Green Mignonett.