Effects of drought stress and exogenous abscisic acid on reprodutive meristem structure, morphology, yield and yield components of oilseed rape (Brassica napus L.)

This study was designed to determine the effects of drought stress and exogenous abscisic acid on the structure of reproductive meristem, pollen grains, morphological traits, yield and yield components of Brassica napus. Plants were grown in Karaj Seed and Plant Improvement Institute in a randomized blocks design with 3 replications. Treatments included irrigated plants without exogenous abscisic acid, under drought stress without exogenous abscisic acid and under drought stress with 3 concentrations of exogenous abscisic acid. Reproductive meristem and anthers of control and treated plants were fixed in proper fixative for cyto-histological studies. Plants were collected for studying the morphological traits, yield components and seed yield. Results showed that drought stress plus the lowest concentration of exogenous abscisic acid prematured the meristem, increased the number of pollen grains and their viability. More ribosomes and mithochondria were observed in pollen grains. Drought stress plus the lowest concentration of exogenous abscisic acid showed an increase in yield in comparison with other plants under drought stress also showed 2-3 percent increase in oil percentage.