Exogenous application of paclobutrazol promotes water-deficit tolerance in pepper (Capsicum annuum)

Abstract

Abstract. Slichatun, Khasanah FU, Pitoyo A, Etikawati N, Mudyantini W. 2021. Exogenous application of paclobutrazol promotes water-deficit tolerance in pepper (Capsicum annuum). Cell Biol Dev 5: 1-6. Pepper (Capsicum annuum L.) is a vegetable commodity with high economic value. However, pepper cultivation in Indonesia is still hampered by pests and drought, reducing its growth and production. The efforts to increase pepper productivity and its resistance to drought stress can be conducted by applying growth regulators (ZPT), one of which is paclobutrazol (PBZ). This study aims to determine the effect of PBZ on the growth and accumulation of proline, a plant osmoprotectant, in pepper seedlings grown in water-deficit soil. This study used a completely randomized design (CRD) with two factors, i.e., a variation of PBZ and soil water capacity. PBZ concentration was made in four levels, namely 0 ppm, 25 ppm, and 50 ppm. The variation of the water-capacity level was made in three levels, namely 100% FC (field capacity as well-watered treatment), 75% FC (mild water deficit), and 50% FC (severe water deficit). The treatment was given for three weeks. The quantitative data obtained were analyzed by ANOVA, and if there was a significant difference, a further test was carried out with DMRT at the 95% confidence level. In addition, qualitative data were analyzed descriptively. The results showed that applying PBZ to pepper (Capsicum annuum L.) seedlings that grew under water-deficit stress significantly affected proline levels, total chlorophyll content, and carotenoid levels; meanwhile, the parameters of plant dry weight and root shoot ratio had no significant effect. Furthermore, this indicates that PBZ is quite capable of inducing resistance to pepper seedlings in drought conditions.