Morphophysiological changes during vegetative stage drought stress in the local pigmented rice (Oryza sativa L.) from East Nusa Tenggara

Abstract

The ability of plants to adapt to drought stress is determined by their morphophysiological characteristics. By combining morpho-physiological characters, this study aims to obtain drought tolerance local-pigmented rice cultivars. This study was conducted with nine local pigmented rice cultivars and 2 control cultivars that were treated with 3 field capacity (FCs) levels: 100%(control), 50%(moderate-drought), and 25% (severe-drought). The observation was carried out during the vegetative period (46 days after planting). Evaluation of phenotypic characters showed that Padi Merah Noemuti, Padi Hitam Maumere, Hare Tora and Gogo Metan Noemuti has higher plant height, number of leaves and large number of tillers. Growth reduction analysis showed that Hare-Tora experienced the smallest decline in plant height, the number of leaves and tillers. The physiological analysis of photosynthetic pigments showed that Hare Tora and Kisol had the high chlorophyll content, while the smallest chlorophyll reduction (18%) showed by Gogo Pulut Merah. The highest levels of proline and carotenoid content were observed in Gogo Pulut Merah and Hare Tora while low intercellular content of CO2, high transpiration rate and also the high stomatal conductivity to H2O was shown by Kisol, Padi Merah Noemuti, Hare Tora and Padi Hitam Maumere. The highest relative water content and membrane stability index were observed in Padi Merah Noemuti. Based on morphophysiological and drought tolerance characters, in severe-drought condition, the cultivar of Hare Tora, Kisol, Padi Hitam Maumere, and Padi Merah Noemuti experienced the optimum physiological performance which indicates tolerance to drought stress.