Histochemistry of Corsican Pine Needles Infected by Lophodermella sulcigena (Rostr.) v.Höhn.

Abstract

A histochemical survey was made on lesion development in Pinus nigra (Aiton) Melville infected by Lophodermella sulcigena (Rostr.) v. Höhn. The fungus colonized the intercellular spaces of the mesophyll and then invaded the endodermis, hypodermis and epidermis. All tissues within the lesion were killed. Lesion expansion ceased in autumn when a stationary interface was established between infected mesophyll and healthy host cells at the needle base. The stationary interface was marked by a zone of fungalfree, dead mesophyll cells and the appearance of an intercellular matrix. Extensive hypertrophy and hyperplasia occurred in parenchyma tissues at the interface. Protein, starch and DNA persisted in tanned cytoplasm for many months.