Nitrogen fertilizer application does not always improve available carbohydrate per spikelet but decreases chalkiness under high temperature in rice (Oryza sativa L.) grains
Nitrogen fertilizer application does not always improve available carbohydrate per spikelet but decreases chalkiness under high temperature in rice (Oryza sativa L.) grains
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DOI：
10.1016/j.fcr.2022.108741
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发表时间：
2023-01
影响因子：
5.8
通讯作者：
Olusegun Idowu;T. Katsube-Tanaka;T. Shiraiwa
中科院分区：
文献类型：
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作者：
Olusegun Idowu;T. Katsube-Tanaka;T. Shiraiwa
研究了施氮量与每小穗有效碳水化合物（ACPS）和淀粉体分子伴侣（cpHSP 70 -2）对稻米垩白的影响。连续两年（2020年和2021年），在日本京都不同氮肥和温度条件下，对5个具有不同光周期敏感性、ACPS和cpHSP 70 -2活性的水稻品种进行了研究。这些品种包括中国粳稻辽粳5号（LG 5）的近等基因系（NILs）（具有或不具有直立穗性状（EP或NEP））和日本粳稻品种日本晴、金迷宫和cpHSP 70 -2活性降低的flo 11 -2突变体。结果表明，flo 11 -2的垩白率最高。所有品种的垩白率均随开花后20 d平均日最高气温（Tmax）的升高而升高，随施氮量的增加而降低。垩白率在LG 5-EP中略高，可能是因为ACPS低于LG 5-NEP。然而，颗粒投影面积（从扫描的颗粒图像测量的颗粒面积），这是一个代理的ACPS，与相对垩白率的LG 5-NEP和日本粳稻品种在高温下，负和正相关，分别。Idowu et al.（2022）报道的LG 5近等基因系中籽粒投影面积对氮肥的基因型不同反应，以及ACPS与氮肥剂量之间的负相关性表明ACPS对垩白无关紧要。同时，施氮增加了小麦籽粒中cpHSP 70 -2的积累，说明cpHSP 70 -2参与了施氮降低垩白的过程。
The objective of this study was to understand the relationship between N fertilizer application and available carbohydrates per spikelet (ACPS) or amyloplast molecular chaperones (cpHSP70–2) on rice grain chalkiness. In two consecutive years (2020 and 2021), five rice cultivars with different photoperiod sensitivities, ACPS, and activity in cpHSP70–2 were grown in Kyoto, Japan under varied N fertilizer and temperature applications. The cultivars comprised near-isogenic lines (NILs) of Chinese japonica Liaojing 5 (LG5) with or without an erect panicle trait (EP or NEP) and Japanese japonica cultivars, Nipponbare, Kinmaze, and flo11–2 mutant with reduced activity in cpHSP70–2. The results showed that flo11–2 had the highest chalky ratio. The chalky ratio increased with the average of daily maximum temperature (Tmax) for 20 d after flowering and decreased with N fertilization in all cultivars. The chalky ratio was marginally higher in LG5-EP, possibly because ACPS was lower than in LG5-NEP. However, the grain projection area (grain area measured from a scanned grain image), which is a proxy of ACPS, correlated with the relative chalky ratio for the LG5-NEP and Japanese japonica cultivars at high temperatures, negatively and positively, respectively. The genotypically different responses of grain projection area to N fertilization, along with a negative correlation between ACPS and N dosage in NILs of LG5 reported in Idowu et al. (2022) suggest that ACPS is inconsequential for chalkiness. Meanwhile, N fertilization increased the cpHSP70–2 accumulation per grain, suggesting the involvement of cpHSP70–2 in lowering of chalkiness under N fertilization.