Killi Dilek, Haworth Matthew
Department of Agrifood Production and Environmental Sciences (DiSPAA), University of Florence, Piazzale delle Cascine 28, 50144 Florence, Italy.
The National Research Council of Italy, Tree and Timber Institute (CNR-IVALSA), Presso Area di Ricerca CNR, Via Madonna del Piano 10, Sesto Fiorentino, 50019 Florence, Italy.
Plants (Basel). 2017 Oct 17;6(4):49. doi: 10.3390/plants6040049.
Quinoa ( Willd.) has been proposed as a hardy alternative to traditional grain crops in areas with warm-to-hot climates that are likely to experience increased drought and salt stress in the future. We characterised the diffusive and metabolic limitations to photosynthesis in quinoa exposed to drought and salt stress in isolation and combination. Drought-induced pronounced stomatal and mesophyll limitations to CO₂ transport, but quinoa retained photosynthetic capacity and photosystem II (PSII) performance. Saline water (300 mmol NaCl-equivalent to 60% of the salinity of sea-water) supplied in identical volumes to the irrigation received by the control and drought treatments induced similar reductions in stomatal and mesophyll conductance, but also reduced carboxylation of ribulose-1,5-bisphosphate carboxylase/oxygenase, regeneration of ribulose-1,5-bisphosphate, increased non-photochemical dissipation of energy as heat and impaired PSII electron transport. This suggests that ion toxicity reduced via interference with photosynthetic enzymes and degradation of pigment-protein complexes within the thylakoid membranes. The results of this study demonstrate that the photosynthetic physiology of quinoa is resistant to the effects of drought, but quinoa may not be a suitable crop for areas subject to strong salt stress or irrigation with a concentration of saline water equivalent to a 300 mmol NaCl solution.
藜麦（Chenopodium quinoa Willd.）已被提议作为传统谷物作物的耐寒替代品，用于未来可能面临干旱和盐胁迫加剧的温暖至炎热气候地区。我们分别及综合研究了干旱和盐胁迫下藜麦光合作用的扩散和代谢限制。干旱导致对二氧化碳传输的气孔和叶肉限制显著，但藜麦仍保持光合能力和光系统II（PSII）性能。与对照和干旱处理所接受的灌溉量相同的咸水（300 mmol NaCl，相当于海水盐度的60%）供应，导致气孔和叶肉导度出现类似程度的降低，但也降低了1,5-二磷酸核酮糖羧化酶/加氧酶的羧化作用、1,5-二磷酸核酮糖的再生，增加了作为热量的非光化学能量耗散，并损害了PSII电子传输。这表明离子毒性通过干扰光合酶和类囊体膜内色素-蛋白质复合物的降解而降低。本研究结果表明，藜麦的光合生理对干旱影响具有抗性，但藜麦可能不是适合遭受强盐胁迫或用相当于300 mmol NaCl溶液浓度的咸水灌溉地区的作物。
