Nitric oxide is involved in salicylic acid-induced flowering of Lemna aequinoctialis Welw.

Salicylic acid (SA) is a well-known inducer of flowering in Lemna under both non-inductive and inductive photoperiod conditions. However, the underlying mechanism is not well understood. Herein, we report for the first time that nitric oxide (NO) is partially involved in SA-induced flowering in L. aequinoctialis (Syn. L.paucicostata Hegelm.). Our results demonstrated that SA-induced flowering is significantly reduced by exogenous application of NO scavengers; 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide and methylene blue, nitric oxide synthase inhibitors; N-ω-nitro-l-arginine and N-ω-nitro-l-arginine-methyl ester hydrochloride, and nitrate reductase inhibitor; sodium tungstate in two strains of Lemna viz. 6746 and LP6. Altogether our present findings shed a light on the new role of NO in SA-induced flowering and open interesting directions that need further investigation.