Factors influencing flower and pod development in oil-seed rape (Brassica napus L.)

Abstract

SummaryExperiments were carried out on oil-seed rape, variety Zollerngold, to determine the effects on flower and pod development when (1) the supply of carbon assimilates was reduced by shading or leaf removal at different stages of development or (2) the supply of assimilates to the more apically positioned flowers or pods on the terminal raceme was increased by removing 15 of the most basal flowers or pods.A decrease in the production of carbon assimilates led to fewer flowers and pods developing to maturity and when the stress continued over most of the period of pod development the pods were smaller and had fewer seeds which were also lighter in weight.Removal of the 15 basal flowers or pods led to more of the apically positioned flowers developing into mature pods and the other pods becoming heavier with bigger husks, heavier seeds and sometimes a greater number of seeds.The results of a shading experiment in a controlled environment cabinet suggest that stresses in the supply of carbon assimilates around the time of anthesis are particularly harmful since in addition to reducing the number of pods which develop they appear to restrict the capacity for compensatory growth in the pods that remain when the supply returns to normal.