Ultrastructure of haustorium development in Puccinia coronata avenae. I. Cytochemistry and electron probe X-ray analysis of the haustorial neck ring

Abstract

The structure and composition of the haustorial neck ring in Puccinia coronata avenae was determined by histochemical methods and by electron-probe X-ray analysis (EDX). In mature haustoria, the neck ring structure was composed of two cylindrical bands. A broad band, nearer to the haustorial mother cell, was designated as the α (alpha) band and a narrower band, nearer to the haustorial body, the β (beta) band. The chemical composition of the two bands was different. The results of EDX analysis showed silicon as the major element present in the α band, and iron and phosphorus (possibly in the form of ferric pyrophosphate), the major elements of the β band. Digestion with protease or treatment with the organic solvents chloroform–methanol, ether–ethanol, or acetone failed to extract either band, indicating the presence of little, if any, protein or lipid materials.