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. | Turk J Biol 31 (2007) 103-107 © TÜB‹TAK Photosynthetic and Yield Responses of Nigella sativa L. to Pre-sowing Seed Treatment with GA3 Shoukat Hussain SHAH Plant Physiology Section, Department of Botany, Aligarh Muslim University, Aligarh-202 002, INDIA Received: Abstract: 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 (. ), 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%. Key Words: Dry mass, carbonic anhydrase, leaf area, chlorophyll, black cumin, net photosynthetic rate, stomatal conductance, seed yield Abbreviations: GA3 – gibberellic acid; CA – carbonic anhydrase; Chl – chlorophyll; DAS – days after sowing; gS – stomatal conductance; PN – net photosynthetic rate; GAs – gibberellins; RuBPCO – ribulose – 1,5 – biphosphate carboxylase / oxygenase; ER – endoplasmic reticulum. Introduction Black cumin is a Middle Eastern herb used since antiquity by the Romans for aromatic and culinary purposes and by the Arab pharmacists and herbalists to cure numerous ailments such as pityriasis, leucoderma, ringworm, eczema, chest congestion, migraine, paralysis, and rheumatism (1). Recently, because of concerns about the harmful side effects of allopathic drugs, there has been a dramatic reversion of preference towards the use of herbal medicines to cure
