Correlation of Fluorescent Appearance in Papilla with Unsuccessful Penetration Attempts in Susceptible Barley Inoculated with Erysiphe graminis f. sp. hordei

Abstract

In susceptible barley to Erysiphe graminis f. sp. hordei race I, the relation between fluorescent appearance in papilla and fungal penetration attempts was examined using light and fluorescent microscope. In the primary penetration course, fluorescent appearance was detected in all papillae where inoculated conidia ceased the penetration into host epidermal cells, whereas the papillae which permitted the successful penetration attempts did not show any fluorescent appearance. In halo, the same fluorescent appearance was observed regardless of success or failure of fungal penetration. These cytological responses were also observed in the secondary or tertiary penetration sites 72hr after inoculation. These results suggested that accumulation of fluorescent compound in papilla was essential for the prevention of fungal penetration in powdery mildew of barley.