Studies in the Physiology of Virus Diseases in Plants

SUMMARY It has been shown that the symptoms induced by aucuba or yellow mosaic of tomato in certain other members of the Solanaceae (notably N. glutinosa and D. stramonium) differ markedly from those in tomato. Neither formation of intracellular inclusions nor systemic infection occurs in these plants. In N. glutinosa, the symptoms appear only on the rubbed portion of the leaves and little multiplication of the virus takes place. In D. stramonium, although no mosaic symptoms appear on the host, the virus travels through the tissues and can infect susceptible grafts. Holmes' work on the use of N. glutinosa as a ready means of demonstrating the presence of the virus agent in a juice has been confirmed and amplified. It has also been shown that it is possible to inject the intercellular spaces of the leaf of N. glutinosa with virus juice and that no infection occurs unless cells have been ruptured.