A scanning electron microscopy and X-ray microanalysis study during induction of morphogenesis in Camellia japonica L.

Abstract

A scanning electron microscopy (SEM) study during the induction of direct and indirect morphogenesis (root and embryo formation) from leaves of Camellia japonica L. showed that the induction of morphogenesis is linked to the appearance of a layer of fibrillar material covering the surface cells of induced leaves and calli. Before embryo formation a 2nd deposition of material of smooth texture occured being the embryogenic regions of calli and globular embryos totally covered by a layer of this material. A positive reaction to aniline blue staining suggests that a deposition of ‘callose’ precedes embryo formation. Results of electron probe microanalysis (EPMA) during direct morphogenesis show higher levels of Ca, K, Na, Fe and S in leaf-induced parenchyma cells which decrease with the onset of morphogenesis. Results suggest a correlation between X-ray spectra and the in vitro response obtained (calli, embryogenesis, rhizogenesis). Identical X-ray spectra were obtained for both globular somatic and zygotic embryos. Roots also presented identical X-ray spectra independently of their origin. Can X-ray microanalysis be used to diagnose cell competence and determination?