Crystal-like structures in plastids of tomato roots, infested by Meloidogyne incognita

Abstract

Crystalline inclusions occur in the cytoplasm of healthy cells in many plant species and represent protein storage structures or the accumulation of fraction-I protein or enzymes. The inclusions are of various sizes and shapes and have been found in cell constituents such as spherosomes, mitochondria and plastids (Marinos, 1967; Martelli and Russo, 1977; Newcomb, 1967). Crystalloids have often been observed in the plastids of bean leaves treated with hypertonic solutions or poisonous gases (Shumway et al., 1967; Gunning et al., 1968; Wrischer, 1973). There are cases in which ordinary crystalline cell contituents are much more abundant in diseased than in healthy cells. Esau (1975) related the higher number of the intraplastidial protein crystals, found in yirus infected cells in spinach, as compared to healthy cells, to an effect of the causal agent on the metabolism and sugar translocation in leaves. The results of cytological studies carried out to determine numerical and morphological differences between plastids in healthy and infested tomato roots, resistant to Meloidogyne incognita (Kofoid et White) Chitw., are discussed in this paper.