Short-term drought exposure decelerated growth and photosynthetic activities in chili pepper (Capsicum annuum L.)

Abstract

Chili pepper (Capsicum annuum L.) is a preferred vegetable by local farmers at a riparian wetland in Indonesia due to high market demand and its economic value. Chili pepper can be grown immediately after rice harvesting, concurrently with the early dry season. Three chili pepper varieties, namely Genie, Romario, and Laris were evaluated for their adaptability to drought condition. Drought treatment was imposed for 7 days until soil water potential was dropped to around −30 to −40 kPa. Morphological and photosynthetic traits were measured at pre-, during, and post-drought exposures. Growth analysis was calculated based on measured morphological traits. Results indicated that the number of leaves (NoL), total leaf area (TLA), total accumulated dry matter (TDM), and relative growth rate (RGR) were negatively affected by drought. Water content of shoot (SWC), leaf (LWC), and root (RWC) were significantly decreased during drought exposure; yet, able to fully recover at 7 days after drought treatment was terminated. Decrease in shoot root ratio (SRR) and leaf weight ratio (LWR); reversely, increase the root weight ratio (RWR) under drought condition, was not associated with enhancement of root growth. Rather, it was due to less negatively effect of drought on roots than on the above-ground organs. Simultaneously, chlorophyll fluorescence, LWC, stomatal conductance, transpiration and photosynthetic rates declined during drought exposure. However, 7 days after drought treatment was terminated, all traits were able to return to pre-drought levels. Among chili pepper varieties studied, Genie exhibited better overall performance than Laris and Romario did under drought stress condition.