PLANT-GROWTH REGULATORS INFLUENCE (CO2)-C-14 ASSIMILATION AND TRANSLOCATION OF ASSIMILATES IN INDIAN MUSTARD

Effect of plant growth regulators Naphthalene acetic acid (NAA), Gibberellic acid (GA3) and Kinetin on (CO2)-C-14 assimilation, partitioning of C-14 into major biochemical fractions and translocation of assimilates was studied in different parts of Indian Mustard (Brassica juncea) at late ripening stage. Leaves, stem and pod walls are photosynthetically active and are important sources for seed filling. NAA and kinetin increased the (CO2)-C-14 assimilation rate in all the three photosynthetically active parts. All the three growth regulators increased the export of 14 assimilates out of source organs and increased the movement of assimilates into the reproductive parts (pods). The increased movement of photoassimilates into the developing pods may be due to the stimulation of sink activity by the growth regulators which resulted in the higher demand for photoassimilates. It was suggested that growth regulators may increase yield by altering distribution of assimilates in the mustard plants.