The Role of Growth Regulators on Nodule Senescence and Nitrogen Fixation in Soybean

Despite that the number of nodules plant-1 and the diameter of pink bacteroid tissue were higher in Kinetin treatment as compared to other treatments, there was no significant effect determined on Acetylene reduction activity readings in different treatments. The four hormones IAA, ABA, GA and Kinetin did not show clear role on retarding or enhancing nodule senescence. There was no clear cut evident reflect the link between the senescence of upper portions of plant and nodule senescence.