SYNCYTIA DEVELOPMENT IN GERMPLASM PEA ACCESSIONS INFECTED WITH HETERODERA GOETTINGIANA

Abstract

The ultra structure of syncytial development in roots of pea accessions attacked by Heterodera goettingiana Liebscher is described 4 and 10 days after nematode invasion. Four days after inoculation a feeding plug was evident where the stylet had penetrated the wall of the initial syncytial cell. In the cell the fine structure was modified. Nonmembrane-bound materials, which appeared to be nematode secretions, were evident near the stylet terminus and within the syncytial cytoplasm. Syncytia continued to develop in susceptible pea accessions 10 days after nematode invasion. In the modified cells proliferation of actively synthesizing cytoplasm indicate that the syncytial components function as secretory system. At the same time the content of syncytial cells of the resistant pea accessions is strongly disintegrated. The hypersensitive response in terms of physiological cell death is discussed.