The Effect of EGTA, Calcium Channel Blockers (Lanthanum Chloride and Nifedipine) and their Interaction with Abscisic Acid on Seed Germination of Brassica juncea cv. RLM-198

Recent investigations have shown that abscisic acid (ABA) dependsupon the availability of Ca²⁺ for its action in certain systems.In order to check whether ABA requires Ca²⁺ to inhibit seedgermination, the effects of ABA, CaCl₂, EGTA (a Ca²⁺ chelator)and lanthanum chloride and nifedipine (Ca²⁺ channel blockers),individually and in combination, on seed germination of Brassicajuncea L. cv. RLM-198 were studied. ABA inhibited germinationin a concentration dependent manner. ABA-induced inhibitionwas abolished with the lapse of time after application. Calciumneither affected germination nor altered the ABA-induced inhibition.EGTA. La³⁺ and nifedipine suppressed seed germination when testedindividually and further elevated the ABA effect, in a synergisticway, when applied simultaneously. They also prevented the time-dependentreduction in ABA-induced inhibition. The findings indicate thatCa²⁺ is not essential for ABA to cause germination inhibition. EGTA, Ca²⁺ channel blockers, abscisic acid, seed germination, Brassica juncea