Leaf is a sensitive plant organ in responding to abiotic stresses, especially drought stress. Objective of this research was to evaluate changes of relative leaf expansion rate (RLER) and other leaf-related indicators as affected by gradual drought stress. The stress was induced by withholding water supply to chili pepper (Capsicum annum L.) for up to 12 days. Afterward, the crops were allowed to recover. The research was conducted in two stages. The first stage was for finding a reliable leaf area (LA) estimation model. The second stage was for evaluating relevance of RLER, specific leaf fresh weight (SLFW), specific leaf water content (SLWC), and total leaf area (TLA) as indicators for drought stress in chili pepper. Combinations of five regression models (linear, zero-intercept linear, quadratic, zero-intercept quadratic, and power) and three predictors, i.e. leaf length (L), leaf width (W), and LW were evaluated as candidates of LA estimation model. Selection of the models were based on coefficient of determination (R2) and geometrical principles. The selected model was used for calculating RLER, SLFW, SLWC and TLA. Results of this study indicated that dynamic changes of RLER were mainly driven by daily day-night cycle rather than long-term gradual drought stress. SLFW and SLWC did not significantly decrease during drought stress period. However, drought stress significantly inhibited TLA in chili pepper. Chili pepper was able to recover from short-term (4 days) exposure to drought stress; yet, this crop was unable to recover after 8 days exposure to drought stress or longer.
Full article can be downloaded 2017 AJCS Drought stress in chili pepper