Growth and Differentiation of the Epidermal Wall

Waxy coatings on leaves and other plant surfaces have been studied since DeBary\u27s early work. Surface wax has assumed additional importance with the advent of systemic and herbicidal sprays. The retention and absorption of these sprays depend upon the waxy coatings and other properties of the epidermis. Earlier publications have pictured the first development of the cuticle and the extrusion of surface wax through it. None of our observations have demonstrated any channels associated with wax extrusion, and we conclude that it permeates the cellulose matrix of the primary epidermal wall in a softened form, which then hardens on the surface of the leaf

Morphological factors of the central whorl leaf associated with leaf surface wetness and resistance in sorghum to shoot fly, Atherigona soccata

Earlier studies showed that leaf surface water on the central whorl leaf of sorghum seedlings is associated with resistance to shoot fly. In this study, the results of an experiment to determine if leaf surface wetness (LSW) originates from atmospheric condensation or from the plant are described. Morphological structures: trichomes, stomata, leaf cuticle and quantity of surface wax of the central whorl leaf were also examined for their role in LSW production. The results suggest that LSW of the central whorl leaf originates from the plant and is not due to condensation of atmospheric moisture. The presence of trichomes was indirectly associated with LSW and resistance to shoot fly but stomatal density was not associated with LSW production. The amount of wax extracted per 100 mg of fresh weight varied significantly between genotypes and seedling age. It was more in susceptible than in resistant genotypes; however, cuticular thickness was not associated with resistance. It is suggested that LSW could be the result of some form of cuticular movement of water to the leaf surface

Resistance in sorghum to the shoot fly, Atherigona soccata: epicuticular wax and wetness of the central whorl leaf of young seedlings

Sorghum genotypes known to be resistant or susceptible to shoot fly, Atherigona soccata Rondani were examined by scanning electron microscopy for differences in epicuticular wax structure and wetness of the central leaf whorl. Two major types of wax structures were observed: shoot fly resistant and moderately resistant genotypes were characterised by a smooth amorphous wax layer and sparse wax crystals while susceptible genotypes possessed a dense meshwork of crystalline epicuticular wax. The density of wax crystals decreased from the third leaf to the seventh leaf stage and was related to both seedling age and leaf position. Water droplets on susceptible genotypes with dense wax crystals showed spreading at the edges indicating a tendency to wet easily. In resistant genotypes with less dense wax crystals the droplets remained intact and did not spread

Oekologische und oekosystemanalytische Ansaetze fuer das Monitoring von gentechnisch veraenderten Organismen

Available from TIB Hannover: RN 8422(2002,44) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman