Histology of 'Cornus florida' L. Leaves Infected Naturally and Artificially by'Discula' sp

摘要

Portions of healthy and Discula sp. infected leaves of Cornus florida were fixedand processed for light microscopy. The symptomatic leaves were from both naturally and artificially infected plants. Successful greenhouse infections was improved greatly by pretreatment of leaves with weak acid solution at pH 2.5. Healthy leaves were used to assess the normal condition. Intracellular and intercellular hyphae of Discula sp. were abundant in the epidermis, mesophyll, and vascular tissues of artificially and naturally infected leaves. Proliferation of fungal hyphae was accompanied by extensive breakdown of chloroplasts in palisade and spongy parenchyma tissue.