Ultrastructural Changes Associated with the Tanning Process in the Cyst Wall of the Soybean Cyst Nematode, Heterodera glycines ICHINOHE : Ecological significance of dormancy in plant parasitic nematodes. II.

Abstract

At an early stage of development in Heterodera glycines ICHINOHE, irregular bodies were observed in cysts. Phenolic substances were detected at higher concentrations in brown cyst walls than in those with a pale-yellow coloration. These substances were primarily detected in the outer half of the brown cyst wall. Under the electron microscope, the layers of the cyst wall were more clearly observed in brown cysts than those exhibiting a pale color, because of pronounced differences in electron density among layers which were progressively being taned. A fibrous layer with high electron density developed in the innermost layer (C₃) subsequent to the yellow-brown cyst stage.