Effect of drought stress on the cytological status in Ricinus communis

Growing leaves of dicots are characterized by the simultaneous development of cytological structure and physiological function. Cytological development of growing leaves of castor bean (Ricinus communis L.) and the impact of drought on this process was studied, Cell division was observed when the middle lobe of the leaf was below 8 cm length. Cell densities dropped when the middle leaflet had reached 4 cm. Identical relationships between leaf size (length of the middle lobe) and (i) exposed surface area of epidermal cells, (ii) height of palisade cells, (iii) cell density and stomatal density were observed. During drought, areal growth decreased, but the relationships between the cytological parameters and leaf size did not change. The impact of drought on the cellular growth processes depended on the stage of cytological development at the onset of the drought. These results are the basis for an analysis of physiological and biochemical parameters in forthcoming studies.