A study was carried on the photosynthetic efficiency of blackgram to improve the transport efficiency by foliar application of plant growth regulators and nutrient mixture during rabi, 2017-18 as pot culture experiment at glass house of the Department of Crop Physiology. Foliar application of salicylic acid (SA) (250 ppm), mepiquat chloride (MC) (250 ppm), chlorocholine chloride (CCC) (150 ppm) were applied at flower initiation stage and 15 days after the first spray, on blackgram with and without the seed treatment of salicylic acid (50 ppm). TNAU Pulse Wonder (1%) was applied as foliar spray at peak flowering stage. Among the treatments, Mepiquat Chloride (MC) significantly increased chlorophyll content while TNAU Pulse Wonder recorded higher chlorophyll index, transpiration rate, stomatal conductance, seed yield plant-1and seed index. It is concluded that TNAU Pulse Wonder improved the source-sink relationship compared to other treatments with enhanced physiological, biochemical parameters and yield of blackgram.