Stomatal conductance, leaf chlorophyll content, growth, and yield of sweet pepper in response to plant growth regulators

Abstract

ABSTRACTThe demand for sweet pepper (Capsicum annuum L.) is increasing because of nutrition and quality factors. Research to improve pepper yield using plant growth regulators (PGRs) has occurred, but results are not consistent. This study evaluated the effects of the PGRs naphthalene acetic acid (NAA), gibberellic acid (GA3), 4-chlorophenoxyacetic acid, Kelpak® (seaweed extract), and their combinations, on stomatal conductance, leaf chlorophyll content, and growth and yield of hydroponically grown sweet pepper. Seedling root plugs were soaked in Kelpak® at 10 mL L−1, 3 h before transplanting. Thereafter, solutions were applied to foliage with NAA at 20 mg L−1, GA3 at 15 mL L−1, and Kelpak® at 5 mL L−1 and their combinations at 15, 30, and 45 days after transplanting. PGR treatments benefitted stomatal conductance. Leaf chlorophyll content of untreated plants decreased with time compared to treated plants. Foliar application of GA3, alone, and in combination with Kelpak®, increased plant height, fresh and dry biomass, and yield compared to other treatments. Further investigation with application rates, and time of foliar application, on sweet pepper will provide a better understanding of how plants respond to PGRs.