Uptake and Distribution Pattern of Applied Abscisic Acid ( 3 H-ABA) in Normal and Hypernodulating Soybean Varieties (Report‪)‬

Byline: Muhammad Asim, Muhammad Asif, Muhammad Munir and Muhammad Aslam ABSTRACT: The uptake and distribution of abscisic acid (ABA) were studied in inoculated and uninoculated plants of soybean [Glycine max (L.) Merr.] from the time of inoculation to root-nodule initiation (192 hours after inoculation). 3 H-ABA was applied to the leaves of two soybean cultivars: cv. Williams-82 and its hypernodulating mutant, NODI-3. There was a significant difference in the per- cent uptake of 3 H-ABA between the two varieties both in inoculated and uninoculated plants. A marked difference in the percent distribution of 3 H-ABA between different parts of the plants was observed at different developmental phases of root nodules. Leaves of NODI-3 retained more radioactivity as compared to Williams-82 in inoculated as well as uninoculated plants. The stem and roots of Williams-82 plants had a percent distribution of ABA that was higher than NODI-3. The phloem sap of Williams-82 had higher accumulation of 3 H-ABA at all stages after treatment.