Foliar application of NPK and growth regulators enhances vegetative growth and chemical composition in Ficus benjamina L. plants

Abstract: An experiment was conducted from April 2020 to July 2021 to assess the effects of foliar applications of NPK (0, 0.5, 1, and 2 g/L) alongside two concentrations of GA? and BA (150 and 250 ppm) on the vegetative growth and chemical composition of Ficus benjamina L. under greenhouse conditions. Results indicated that applying GA? or BA with NPK at 1 g/L significantly increased plant height, with GA? showing a greater effect on stem diameter than BA. BA promoted branching, and both BA and GA? at 250 ppm enhanced root length and the fresh and dry weights of leaves, stems and roots. The lognest roots were observed with NPK at 2 g/L, while NPK at 1 g/L resulted in the heaviest fresh root weight. The maximum content of carbohydrate and nitrogen was obtained with 0.5 g/L NPK and there was relatively greater accumulation of potassium in plant treated with 1 g/L NPK The GA₃ was more effective than BA in increasing nitrogen and phosphorus content in plants. BA and GA? increased chlorophyll-a and -b, with the combination of BA (150 ppm) and NPK (1 g/L) yielding the highest chlorophyll-b levels. The highest carotenoid content was achieved with NPK at 2 g/L combined with either GA? or BA. Treatment with BA at 150 ppm enhanced the chlorophyll a/b ratio, while GA? at 250 ppm more effectively increased the total chlorophyll-to-carotenoid ratio. These findings suggest that foliar application of NPK at 1 g/L, combined with either BA or GA? (250 ppm), optimizes vegetative growth and enhances the chemical composition of F. benjamina L. under greenhouse conditions, promoting both growth quality and vigor.