Effect of p-sitosterol and Gibberellic Acid on Leaf Angle, Growth, Flowering and Biochemical Constituents of Marigold (Calendula officinalis L.)

摘要

Marigold (Calendula officinalis L.) plant growth and orientation were improved by foliar application of gibberellic acid (GA_3; 25, 50 and 100 mg L~(-1)) and p-sitosterol (20, 40 and 80 mg L~(-1)) singly, or in combination. GA_3 at 25 mg L~(-1) more effective increased the number of branches, fresh and dry weight of shoots and roots/plant while GA3 at 100 mg L~(-1) significantly increased plant height. Leaf angle decreased more with GA_3 than with P-sitosterol application. Both GA3 (100 mg L~(-1)) orp-sitosterol (40 mg L~(-1)) significantly induced flowering earliness and number of inflorescences while a low concentration of both substances improved other inflorescence characters. The GA_3 (100 mg L~(-1)) x p-sitosterol (40 mg L~(-1)) interaction significantly increased earliness, number and stalk length of marigold plant inflorescences. Pigments (Chlorophyll (Chi) a and b, and carotenoids) and biochemical constituents (total sugars, indoles and free amino acids) were significantly enhanced by GA_3 (25 mg L~(-1)) and/or p-sitosterol (20 or 40 mg L'1) as a foliar application. However, the highest concentration of both bioregulators resulted in the highest phenolic content of marigold plant leaves. GA_3 and p-sitosterol were positively correlated to fresh weight of inflorescences and Chl a + b content. There was a significant negative correlation between all results and phenolic content of marigold plant leaves.