摘要:蔬菜不仅是人体所必需的维生素、矿质元素等的重要来源, 其提供的一些植物化学物质也对人体健康产生重要作用。气候变化背景下全球CO2浓度和温度升高等改变了蔬菜的生长条件, 然而气候变化如何影响蔬菜品质及其机理还缺乏全面系统的理解。本文综述了气候变化因子如大气CO2浓度、温度及其相互作用, 以及其与水分和氮素互作(非气候因子)对蔬菜品质的影响及其机制, 并对未来研究方向进行展望, 为气候变化背景下提升蔬菜品质促进人体健康提供依据。目前相关研究主要是通过人工模拟试验和作物生长模拟开展, 总体而言CO2浓度升高使蔬菜中蛋白质、硝酸盐、镁、铁和锌含量降低, 抗氧化能力增加(叶类蔬菜)或减少(果类蔬菜), 糖类和维生素含量增加, 植物素(总硫代葡萄糖苷、番茄红素、β-胡萝卜素等)含量增加。CO2浓度升高影响蔬菜品质的机制可能是: 1)促进了光合作用从而提供了更多的碳源, 增加可溶性糖含量; 2)增强硝酸还原酶(NR)活性和相关基因表达, 且碳水化合物增加可进一步促进NR的转录和翻译后调节, 增加硝酸盐的同化, 从而降低硝酸盐含量; 3)诱导抗坏血酸生物合成和再生途径基因表达, 导致抗坏血酸累积; 4)稀释作用、氮分配改变、气孔导度和呼吸作用降低、Rubsico酶合成减少、养分利用率和根系分泌物增加都可能导致蔬菜中矿质元素含量下降。温度升高总体上降低了蔬菜品质, 这是由于高温胁迫通过影响光反应电子传递中光系统Ⅱ和卡尔文循环暗反应Rubisco酶活性来限制光合作用。CO2浓度升高和温度升高的交互作用导致蔬菜品质整体下降。高CO2浓度下, 减少灌水和适量氮供应均可提高蔬菜品质。未来需要采取跨学科的综合方法结合生理学和基因组来研究蔬菜对环境变化的响应, 并研究气候适应性的品种和栽培措施。
关键词:气候变化/
大气CO2浓度升高/
温度升高/
蔬菜/
营养品质
Abstract:Vegetables are an important source of essential vitamins and mineral elements and provide phytochemicals that play an important role in human health. Increases in global carbon dioxide (CO2) concentrations and temperature have changed the growth conditions of vegetables. However, the mechanism by which climate change affects vegetable quality is not fully understood. In this paper, the effects of climate change factors, such as CO2, temperature, and their interactions, as well as their interaction with water and nitrogen (non-climatic factors) on vegetable quality, are briefly reviewed. At present, researches in this field mainly use artificial simulation experiments and crop growth simulation models. Under elevated CO2 concentrations, the contents of proteins, nitrate, magnesium, iron, and zinc in vegetables decrease, and the antioxidant capacity increases for leafy vegetables and decreases for fruit vegetables. The contents of carbohydrates, vitamins, and phytochemicals (e.g., total glucosinolates, lycopene, and beta-carotene) increase with elevated CO2. The physiological process may explain why elevated CO2 levels affect vegetable quality. 1) Elevated CO2 concentrations promote photosynthesis and thus provide more carbon, increasing the soluble sugar content. 2) Elevated CO2 enhances the activity of nitrate reductase (NR) and related gene expression, and the increase in carbohydrate content can further promote the transcription and post-translational regulation of NR, which increases nitrate assimilation and reduces nitrate content. 3) Elevated CO2 also induces the expression of genes involved in ascorbic acid biosynthesis and regeneration, leading to the accumulation of ascorbic acid. 4) The dilution effect, change in nitrogen distribution, decrease in stomatal conductance, respiration, and Rubisco synthesis, and increase in nutrient utilization and root exudates may lead to decreased mineral elements in vegetables under elevated CO2. Global warming generally decreases vegetable quality. Heat stress restricts photosynthesis by affecting electron transport in photosystem Ⅱ during photosynthesis and the activity of Rubisco in the Calvin cycle dark reaction, affecting vegetable quality. The interaction between elevated CO2 concentration and increased temperature results in an overall decline in vegetable quality. Reducing irrigation and using a moderate nitrogen supply could improve vegetable quality under elevated CO2 concentrations. Future vegetable production requires the application of an interdisciplinary and integrated approach that combines physiology and genomics to study the responses of vegetables to climate change.
Key words:Climate change/
Elevated CO2 concentration/
Increased temperature/
Vegetables/
Nutritional quality
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