Gibberellic Acid (GA3) Enhances biomass production, nitrogen accumulation and crude protein content of Sesbania Aculeata Pers. at Seedling Stage

Abstract

The use of plant growth regulators has been highlighted as a very essential practice in agriculture. A pot experiment was designed and conducted in a green-house of the Department of Soil Science, Faculty of Crop Production, SAU, Tandojam. The aim of the experiment was to investigate the influence of different concentrations of gibberellic acid (GA₃) on the vegetative growth, development and biomass yield of a commercially important plant species locally called Manjhandri (Sesbania aculeata Pers.). The experiment was laid out in a complete randomized design with three replications. The seed was purchased from the market and sown in the pots by placing ½ inch deep in soil. After one week the seedlings were thinned to allow single plant per pot. The crop was irrigated with canal water and fertilized with chemical macronutrient fertilizer (ENGRO-NPK) based on their specific growth requirement. Thirty-days after planting the seedlings were sprayed with GA₃ solutions: The GA₃ concentrations included in the study for spray were: G₀ = Control (without GA₃ application), G₁ = 40 mg L^-1, G₂ = 60 mg L^-1, G₃ = 80 mg L^-1, G₄ = 100 mg L^-1 and G₅ = 120 mg L^-1 (in G₅ treatment, seedlings could not survive, hence this treatment was excluded from the study). The data were recorded for plant height, number of composite leaves (plant^-1), shoot and root fresh and dry weights and stem girth (mm). The results obtained from the study revealed that almost all the recorded growth and development traits of Sesbania aculeata Pers. were significantly affected by GA₃. The seedlings sprayed with 40, 60, 80 and 100 mg L^-1 GA₃ showed 10, 31, 44 and 63% increase in height; 22, 35, 58 and 81% increase in number of composite leaves (plant^-1); 33, 59, 83 and 148% increase in shoot fresh weight; 15, 27, 49 and 90% increase in root fresh weight; 45, 73, 98 and 169% increase in shoot dry weight; 18, 34, 52 and 75% increase in root dry weight; 14, 28, 38 and 62% increase in stem girth and 32, 38, 70 and 81% increase in nitrogen and crude protein over unsprayed (control) seedlings, respectively.  The results advocate that the application of GA₃ (100 mg L^-1) at seedlings stage improves growth and development of Sesbania aculeata. Hence, GA₃ can be used to spray this industrially important plant species.