| dc.description.abstract | Changes in environmental factors result from global climate change, one of which is low rainfall which results in drought. Drought stress severely threatens global rice production, which can reduce rice production. Antioxidants can increase tolerance and reduce plant sensitivity to lack. The research was conducted at the greenhouse of the faculty of agriculture, University of North Sumatra, Medan from July to December 2022. The research used a randomized block design with 2 factors. The first factor was the drought stress level (percentage of soil water content) of 3 levels: 80%, 60% and 40% field capacity (FC). The second factor was antioxidants application of 4 levels: 0 mM, ascorbic acid 1 mM, salicylic acid 1 mM and ascorbic acid 0.5 mM + salicylic acid 0.5 mM. The result showed that the drought stress treatments decreased leaf area, root length, root volume, number of total and productive tillers, shoot and root dry weight, relative water content of the leaves, chlorophyll a and total, number of grains per clump, weight of 1.000 grains of rice and dry grain weight per clump, while the drought stress treatments indicate that late flowering, increased the activity of hydrogen peroxide, SOD and POD enzymes, proline content and percentage of empty grains per hill. Antioxidant treatments increased leaf area, root length, number of total and productive tillers, relative water content of the leaves, chlorophyll a, proline content, while decreased root volume, relative water content of the leaves, activity of hydrogen peroxide, POD enzyme, dry grain weight per clump and indicate that fast flowering. Interactions between 40% FC of drought stress with application of increased plant height, leaf area, root length, number of total and productive tillers, shoot root ratio, chlorophyll a and b, number of grains per clump and weight of 1.000 grains of rice, while decreased root volume, flowering time, shoot and root dry weight, relative water content of the leaves, SOD and POD enzymes, percentage of empty grains per hill and dry grain weight per clump. | en_US |
