Root cell response in rice attacked by Hemicycliophora typica

Abstract

The sheath nematode Hemicycliophora typica fed exclusively on emerging root tips of rice seedlings. Response to nematode feeding was the transformation of root tip cells to form a syncytium. Electron microscopy observations indicated that syncytia were formed by perforations in the cell walls. Abnormal perforations were apparent 2 days after nematode inoculation. The site of the perforations increased as"rr'ematode feediug continued and at 7 days, all of the root tip was transformed into a large syncytium, connected to the site where the nematode seemed to have inserted its stylet. The formation of the syncytium involved deterioration of the cytoplasm; the nuclei were free within the amorphous background. Similarities between the syncytia induced by H. typica and endoparasitic nematodes are discussed.