GIBBERELLINS AND EARLY DISEASE SYNDROME OF ASPERMY VIRUS IN TOMATO (LYCOPERSICON ESCULENTUM MILL)

A quantitative examination of the development of the disease syndrome created by as permyvirus in tomato (Lycopersicon esculentum Mill., cultivar Potentate) revealed an early reduction in subapical mitotic activity which led to the development of smaller internodes. Later symptoms were associated with necrosis of young axillary buds and the failure of a new vegetative apex to develop once flower initiation had begun in the primary apical bud.Application of gibberellic acid (GA3) to the growing point tended to reverse virus-induced stunting by increasing cell expansion but the response was less than that in healthy plants. This was due to a reduction in the number of mitoses associated with virus infection. No consistent difference was found between the endogenous gibberellin levels of healthy and infected plants. It is suggested that the most important single factor in early symptom development is a virus-induced reduction in cell division which cannot be overcome by applying GA3. © 1968 OXFORD UNIVERSITY PRESS.