Surface sterilized seeds of black cumin (Nigella sativa L.) were soaked in 10-6, 10-5, or 10-4 M aqueous solution of gibberellic acid (GA3) for 5, 10, or 15 h and sown in pots with sandy loam soil. The plants were then sampled at 50, 70, and 90 days after sowing, for the analysis of shoot length, leaf area, dry mass, carbonic anhydrase activity (E.C. 4.2.1.1), leaf chlorophyll content, stomatal conductance, and net photosynthetic rate. Seed yield was recorded at harvest (130 DAS). All parameters were found to be significantly enhanced by the hormone (GA3) treatment, with maximum stimulation being noted following a 10-h soaking treatment with 10-5 M GA3. Moreover, the mentioned parameters were elevated by 70%, 68%, 65%, 39%, 44%, 37%, and 44% over the control at the 70 DAS stage. The seed yield was enhanced by 32%.

Surface sterilized seeds of black cumin (Nigella sativa L.) were soaked in 10-6, 10-5, or 10-4 M aqueous solution of gibberellic acid (GA3) for 5, 10, or 15 h and sown in pots with sandy loam soil. The plants were then sampled at 50, 70, and 90 days after sowing, for the analysis of shoot length, leaf area, dry mass, carbonic anhydrase activity (E.C. 4.2.1.1), leaf chlorophyll content, stomatal conductance, and net photosynthetic rate. Seed yield was recorded at harvest (130 DAS). All parameters were found to be significantly enhanced by the hormone (GA3) treatment, with maximum stimulation being noted following a 10-h soaking treatment with 10-5 M GA3. Moreover, the mentioned parameters were elevated by 70%, 68%, 65%, 39%, 44%, 37%, and 44% over the control at the 70 DAS stage. The seed yield was enhanced by 32%.