THE DEVELOPMENT OF THE STRIPE RUST PATHOGEN PUCCINIA GLUMARUM IN WHEAT LEAVES DURING THE INCUBATION PERIOD
ARMY BIOLOGICAL LABS FREDERICK MD
Pagination or Media Count:
It was confirmed that the penetration of the spore infection P. glumarum into the leaf occurs only through the stomata. Within a day or two after inoculation the fungus penetrates into the tissue of the upper epidermis, forming a substomatal sac, or growth hypha, which is sometimes binucleate. The first four days the fungus develops very slowly in the leaf tissues in the form of short hyphae and localizes primarily around the stomata in the cells of the upper epidermis. On the 6th-8th day there occurs a more intense growth of the rust and a spread along the entire tissue of the leaf. Within 11-14 days the formation of pustules is noted at 16-18C. In the places where pustulation occurs, there is a disruption of the leafs cellular structure and complete destruction of the chloroplasts. The thin walled, slightly septate mycelium of the rust fungus is easily discernable in its growing part in the plant tissue around the stomata prior to and at the moment of sporulation. The remaining portion is deprived of its contents and reduced to thin colorless hyphae that are weakly discernable in the tissue of the parenchyma. Under conditions of etiolation also the inoculation of the leaf occurs, but the fungus, when penetrating into the tissue, forms only the short hyphae of the mycelium and on this the development evidently ceases. With a transfer of the etiolated plants into conditions of natural light, however, the development of the rust is resumed and the fungus is able to sporulate.
- Anatomy and Physiology