Guan'gai paishui xuebao (Jul 2022)
Response of Oxidation Resistance and Yield of Rice to Onset and Recession of Waterlogging
Abstract
【Objective】 The plum rainy season from May to July in southern China is a period where rice accumulates nutrients. The purpose of this paper is to explore the effects of onset, duration of flooding and recession of waterlogging in this period on oxidation resistance and yield of rice in the catchment of Poyang Lake. 【Method】 Pot experiments with Semilate rice as the model plants were conducted when the crop was in the elongation stage. Sediment contents of the surface water was 0 kg/m3 (S0), 0.10 kg/m3(S1) and 0.25 kg/m3 (S2), respectively. For each sediment content, there were two waterlogging treatments with the duration of surface-flooding being 3d (F1) and 6 d (F2) respectively. For each sediment and waterlogging combination, there were two drainages with the duration of the surface water receding being 3 d (D1) and 6 d (D2) respectively. The control was without taking interferences (CK). In each treatment, we measured the SPAD, activity of antioxidant enzymes in the flag leaves and the rice yield. We then analyzed the response of the rice to waterlogging and its associated recession. 【Result】 ①The SPAD decreased with the increase in sediment content, duration of flooding and its recession; it peaked prior to the onset of the drainage. The greatest SPAD fall was in S2+F2+D2, decreasing by 46.20% compared to the CK. ②The activities of SOD and POD, as well as MDA content increased first followed by a decline as the waterlogging recessed; they all peaked prior to the starting of the drainage. ③Waterlogging reduced the 1 000-grain weight and hence the grain yield significantly, compared to the CK (P<0.05), especially S0+F2+D2 and S2+F2+D2 whose yield was down by 52.22% and 52.00%, respectively, than the CK. 【Conclusion】 The enhanced oxidation resistance in semilate rice leaves due to waterlogging at the elongation stage reduced the grain yield. Among the three factors we investigated, duration of flooding and flooding recession affected the rice yield more. To alleviate yield reduction, the duration of the waterlogging and the time it takes to drain the flooding should be less than six days.
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