Salicylic acid an emerging growth and flower inducing hormone in marigold (Tagetes sp. L)

Abstract

Salicylic acid (SA) is an emerging plant growth regulator that acts as signaling molecule in plants under biotic and abiotic stresses. SA also exerts a stimulatory effect on different physiological processes of plant growth but its association with leaf pigments and flowering is less known. Current experiment was conducted to evaluate the effect of exogenous application of different doses of SA on marigold (Tagetes sp.) in greenhouse condition. Marigold (Tagetes sp. L) plants were randomly divided in 4 groups and treated exogenously with four different concentrations of SA (T0: 0 (only water), T1: 40, T2: 80 and T3: 120 mg/L). The solutions were sprayed on aerial parts of plant after 60 days of sowing. Results analysis showed that T3 (120 mg/L SA solution) showed maximum number of leaves plant-1 (30.38), highest plant height (50.63 cm), more number of inflorescence, greater stem diameter (7.84 mm), maximum fresh weight of flowers (11.90 g), and maximum dry weight of flower (1.25 g). Whereas, minimum number of leaves (22.74), lowest plant height (40.8 cm), less number of inflorescence, smaller stem diameter (4.75 mm), minimum fresh flower weight (7.13 g), and minimum dry flower weight (0.7 g) were observed in T0. Furthermore, various leaf pigments were found higher in T3. Present study concluded that T3 treatment of SA improved leaf pigments and morphometric parameters in Marigold. From the aforementioned results, it is suggested that 120 mg/L concentration of SA should be sprayed exogenously before flowering stage, on marigold plants for better growth and flower production.