Analysis of the relative increase in photosynthetic O2 uptake when photosynthesis in grapevine leaves is inhibited following low night temperatures and/or water stress
Analysis of the relative increase in photosynthetic O2 uptake when photosynthesis in grapevine leaves is inhibited following low night temperatures and/or water stress
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DOI：
10.1104/pp.121.2.675
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发表时间：
1999-10-01
期刊：
影响因子：
7.4
通讯作者：
Osmond, CB
中科院分区：
文献类型：
--
作者：
Flexas, J;Badger, M;Osmond, CB
我们发现夜间低温（5摄氏度-10摄氏度）和缓慢施加的水分胁迫对葡萄藤（葡萄属vinifera L.）光合作用的影响之间存在相似之处。叶子暴露在室外生长的植物连续寒冷的夜晚造成光和CO2饱和光合O-2的演变下降到零5天内。经过四个温暖的夜晚，植物恢复了健康。这些光合反应在盆栽植物中得到证实，即使根被加热。光照一段时间后，低温的抑制作用更大，可能是因为蒸腾诱导更高的水分亏缺。气孔关闭只是光合作用抑制的一部分。荧光测量表明没有光抑制的证据，但非光化学猝灭增加，在强调植物。这两个应力的最典型的反应是增加的比例，电子传输净O-2的演变，即使在高外部CO2浓度。氧同位素交换表明，这种不平衡是由于增加O-2吸收，这可能有两个组成部分：光呼吸和Mehler反应。寒冷和干旱引起的水分胁迫增强了O-2吸收过程，这两个过程保持相对较高的电子流率CO2交换接近零，在胁迫叶片。据推测，与O-2吸收过程相关的高电子传递也保持了高Δ pH，从而提供光保护。
We found similarities between the effects of low night temperatures (5 degrees C-10 degrees C) and slowly imposed water stress on photosynthesis in grapevine (Vitis vinifera L.) leaves. Exposure of plants growing outdoors to successive chilling nights caused light- and CO2 saturated photosynthetic O-2 evolution to decline to zero within 5 d. Plants recovered after four warm nights. These photosynthetic responses were confirmed in potted plants, even when roots were heated. The inhibitory effects of chilling were greater after a period of illumination, probably because transpiration induced higher water deficit. Stomatal closure only accounted for part of the inhibition of photosynthesis. Fluorescence measurements showed no evidence of photoinhibition, but nonphotochemical quenching increased in stressed plants. The most characteristic response to both stresses was an increase in the ratio of electron transport to net O-2 evolution, even at high external CO2 concentrations. Oxygen isotope exchange revealed that this imbalance was due to increased O-2 uptake, which probably has two components: photorespiration and the Mehler reaction. Chilling- and drought-induced water stress enhanced both O-2 uptake processes, and both processes maintained relatively high rates of electron flow as CO2 exchange approached zero in stressed leaves. Presumably, high electron transport associated with O-2 uptake processes also maintained a high Delta pH, thus affording photoprotection.