X-ray microanalysis of leaf tumors from maize plants experimentally infected with maize rough dwarf virus: scanning and transmission electron microscopic study.

X-Ray microanalysis, performed by both scanning and transmission electron microscopes equipped with energy-dispersive spectrometers (EDS), was used to analyze the element distribution in phloem tumors induced by maize rough dwarf virus (MRDV) in Zea mays L. The content of both Si and Ca was lower in tumors than in the nontumoral surrounding tissues. The Si content increased in old tumors where this element was mainly concentrated in the trichomes growing at their surface. The peaks of other detectable elements, P, K, and S, were higher in tumor than in nontumor tissues. The distribution of inorganic cations in the cells was also studied by the potassium pyroantimonate (KPA) precipitation technique. The KPA precipitates have proved to be primarily of calcium salts and they occurred quite frequently in the cells at the tumor periphery.