ABSTRACT

Water shortage is the main limitation for agricultural production in many parts of the world. Drought or unavailability of water may seriously limit plant growth as well as yield. A pot experiment was carried out to evaluate the effects of various irrigation strategies, i.e., Full (FI), deficit (DI) and partial root-zone drying (PRD) on physiological, biochemical and yield-related attributes of cotton crop. Irrigation treatments started 60 days after planting and lasted for 60 days. For FI and DI, 100% and 50% of evapotranspiration (ET) was replaced by irrigating the entire pot surface every 4–5 days. For PRD, root system was split into two equal halves and during each irrigation event, only one-half of the root system was irrigated with the same amount of water as applied to DI, and subsequently, irrigation was switched to the second half.PRD irrigation significantly improved WUE, which was 21% and 26% higher than FI and DI, respectively. Higher ABA production under PRD reduced stomatal conductance and net photosynthesis. The activity of antioxidant enzymes namely superoxide dismutase, peroxidase, catalase and ascorbate peroxidase was significantly higher under PRD than DI and FI. Magnitude of osmotic adjustment (i.e. total sugar and proline content) was lowest and highest under FI and PRD, respectively. However, PRD reduced chlorophyll content index, seed cotton yield and fiber quality (fiber strength, fiber length, fiber fineness) as compared to FI. The results indicated that despite improving the WUE, PRD tended to compromise the yield and quality of cotton crop. Results imply that PRD treatment can be an option under water shortage; however, its suitability and efficacy should further be tested under field conditions by applying irrigation water in alternate rows.

摘要

水资源短缺是世界许多地区农业生产的主要限制因素。干旱或缺水可能会严重限制植物的生长和产量。进行盆栽试验以评估各种灌溉策略，即完全（FI）、亏缺（DI）和部分根区干燥（PRD）对棉花作物生理、生化和产量相关属性的影响。灌溉处理在种植后 60 天开始并持续 60 天。对于 FI 和 DI，100% 和 50% 的蒸散量 (ET) 被每 4-5 天灌溉一次整个盆表面所取代。对于 PRD，根系被分成相等的两半，在每次灌溉事件中，只有一半的根系用与 DI 相同的水量灌溉，随后，灌溉切换到后半部分。珠三角灌溉显着提高了 WUE，分别比 FI 和 DI 高 21% 和 26%。PRD 下较高的 ABA 产量降低了气孔导度和净光合作用。抗氧化酶即超氧化物歧化酶、过氧化物酶、过氧化氢酶和抗坏血酸过氧化物酶的活性在 PRD 下显着高于 DI 和 FI。渗透调节的幅度（即总糖和脯氨酸含量）分别在 FI 和 PRD 下最低和最高。然而，与 FI 相比，PRD 降低了叶绿素含量指数、籽棉产量和纤维质量（纤维强度、纤维长度、纤维细度）。结果表明，尽管提高了 WUE，但珠三角地区往往会损害棉花作物的产量和质量。结果表明，在水资源短缺的情况下，珠江三角洲治理可以成为一种选择；然而，