Gao Bo, Hu Shaowu, Jing Liquan, Wang Yunxia, Zhu Jianguo, Wang Kai, Li Hongyang, Sun Xingxing, Wang Yulong, Yang Lianxin
Key Laboratory of Crop Genetics and Physiology of Jiangsu Province, Co-Innovation Center for Modern Production Technology of Grain Crops of Jiangsu Province, Yangzhou University, Yangzhou, China.
Jiangsu Coastal Area Institute of Agricultural Sciences, Yancheng, China.
Front Plant Sci. 2021 Dec 23;12:788104. doi: 10.3389/fpls.2021.788104. eCollection 2021.
Evaluating the impact of increasing CO on rice quality is becoming a global concern. However, whether adjusting the source-sink ratio will affect the response of rice grain quality to elevated CO concentrations remains unknown. In 2016-2018, we conducted a free-air CO enrichment experiment using a popular cultivar grown at ambient and elevated CO levels (eCO, increased by 200 ppm), reducing the source-sink ratio cutting leaves (LC) at the heading stage, to investigate the effects of eCO and LC and their interactions on rice processing, appearance, nutrition, and eating quality. Averaged across 3 years, eCO significantly decreased brown rice percentage (-0.5%), milled rice percentage (-2.1%), and head rice percentage (-4.2%) but increased chalky grain percentage (+ 22.3%) and chalkiness degree (+ 26.3%). Markedly, eCO increased peak viscosity (+ 2.9%) and minimum viscosity (+ 3.8%) but decreased setback (-96.1%) of powder rice and increased the appearance (+ 4.5%), stickiness (+ 3.5%) and balance degree (+ 4.8%) of cooked rice, while decreasing the hardness (-6.7%), resulting in better palatability (+ 4.0%). Further, eCO significantly decreased the concentrations of protein, Ca, S, and Cu by 5.3, 4.7, 2.2, and 9.6%, respectively, but increased K concentration by 3.9%. Responses of nutritional quality in different grain positions (brown and milled rice) to eCO showed the same trend. Compared with control treatment, LC significantly increased chalky grain percentage, chalkiness degree, protein concentration, mineral element levels (except for B and Mn), and phytic acid concentration. Our results indicate that eCO reduced rice processing suitability, appearance, and nutritional quality but improved the eating quality. Rice quality varied significantly among years; however, few CO by year, CO by LC, or CO by grain position interactions were detected, indicating that the effects of eCO on rice quality varied little with the growing seasons, the decrease in the source-sink ratios or the different grain positions.
评估二氧化碳浓度升高对稻米品质的影响正成为全球关注的问题。然而，调整源库比是否会影响稻米品质对二氧化碳浓度升高的响应仍不清楚。在2016 - 2018年期间，我们使用一个常见品种进行了自由空气二氧化碳富集实验，该品种分别种植在环境二氧化碳浓度和升高的二氧化碳浓度（eCO，升高200 ppm）条件下，并在抽穗期通过剪叶（LC）降低源库比，以研究eCO和LC及其相互作用对稻米加工品质、外观品质、营养品质和食味品质的影响。三年的平均值显示，eCO显著降低了糙米率（-0.5%）、精米率（-2.1%）和整精米率（-4.2%），但增加了垩白粒率（+22.3%）和垩白度（+26.3%）。值得注意的是，eCO提高了米粉的峰值粘度（+2.9%）和最低粘度（+3.8%），但降低了回生值（-96.1%），并提高了米饭的外观（+4.5%）、粘性（+3.5%）和平衡度（+4.8%），同时降低了硬度（-6.7%），从而使适口性提高（+4.0%）。此外，eCO显著降低了蛋白质、钙、硫和铜的浓度，分别降低了5.3%、4.7%、2.2%和9.6%，但钾浓度增加了3.9%。不同粒位（糙米和精米）的营养品质对eCO的响应呈现相同趋势。与对照处理相比，LC显著增加了垩白粒率、垩白度、蛋白质浓度、矿质元素含量（硼和锰除外）以及植酸浓度。我们的结果表明，eCO降低了稻米的加工适宜性、外观品质和营养品质，但改善了食味品质。稻米品质在年份间差异显著；然而，未检测到显著的年份×二氧化碳、二氧化碳×LC或二氧化碳×粒位的交互作用，这表明eCO对稻米品质的影响随生长季节、源库比的降低或不同粒位的变化较小。
