Regulation of Nitrate Reductase Activity by Abscisic Acid in Poplar (Populus deltoids) Leaves.

Regulation of Nitrate Reductase Activity by Abscisic Acid in Poplar (Populus deltoids) Leaves.

Excised leaves from Populus deltoids incubated in half strength Hoagland’s solution containing 10mM KNO3 as nitrogen source and 25 to 100μM Abscisic acid for 24hr. Nitrate reductase activity were increased at lower concentration (25 μM) of ABA. Different concentrations of calcium (0.1, 0.5 and 1.0mM) with 25μM ABA inhibits the NR activity at lower to higher (0.1 to 1.0mM) concentrations of calcium. Different concentrations of calcium chelator EDTA (0.1 to 1.0mM) and calcium blocker LaCl3 (1.0 to 10.0mM) along with calcium (1.0mM) also decreases NR activity. EDTA specially reduce the availability of extracellular Ca2+ ions and ABA increased the inhibitory effect of LaCl3....