The changes in the growth pattern of peas caused by flower formation

Weekly growth analyses were made of a very late flowering pea line (‘L’) and its medium flowering (‘M’) and early flowering (‘E’) mutants, grown at three photoperiods.The number of stem nodes of young vegetative plants is not affected by the genotype (L, M, E) nor by the day length. In older plants node numbers tend to increase with the day length, but the rate of node formation decreases with flower formation.Internode length is also independent of genotype, but it increases with day length, even in very young plants, and shows a further considerable increase when flower formation starts.Hence, flower formation clearly marks changes in the growth pattern, consisting of a decrease in node formation and an increase in internode length. These effects are primarily brought about by the genes which determine the rate of flower formation.