Studies on the Exogenous Application of Plant Growth Regulators on Morphological and Biochemical Changes in Gladiolus (Gladiolus grandiflorus l.) Leaf

An experiment was conducted following Randomized Block Design at the instructional field of the Department of Floriculture, Medicinal and Aromatic Plants, Uttar Banga Krishi Viswavidyalaya, Pundibari, CoochBehar, West Bengal, India from October, 2013 to April, 2014. Three different plant growth regulators viz., Gibberellic acid (GA3), N6-Benzyladenine (BA) and Triacontanol each at 3 different levels (25ppm, 50ppm and 100ppm) were applied on Gladiolus cv. American Beauty and the effect was compared to control (distilled water). Each treatment was replicated thrice. In the present experiment, application of GA3 25ppm increased the initial leaf length (10.05 cm) and leaf chlorophyll content (62.30 SPAD value) but GA3 50ppm increased the phenol content of leaves (1.84 mg/ g of fresh wt.), whereas, GA3 100ppm increased the leaf protein content (2.49 mg/ g of fresh wt.). Exogenous application of BA 25ppm improved the reducing sugar content of leaves (4.230 mg/g of fresh weight) while, BA 100ppm improved leaf enzymatic activity (1.27 ∆490 nm/min/g fresh weight). Application of Triacontanol 50ppm improved initial plant height (14.49 cm), initial leaf production (3.08), initial and final leaf width (1.68 cm and 2.63 cm respectively), leaf enzyme activity (1.27 ∆490nm/min/g fresh weight) and final leaf length (57.96 cm). Triacontanol 100ppm improved final leaf production (11.61) and plant height (75.67 cm). Results revealed that Triacontanol 50ppm and 100ppm improved the vegetative growth of Gladiolus which is the integral activity towards improvement of the yield attributing characters and hence may be recommended for commercial cultivation of gladiolus in the Terai region of West Bengal.