Photosynthetic quantum efficiency in south-eastern Amazonian trees may be already affected by climate change.
Photosynthetic quantum efficiency in south-eastern Amazonian trees may be already affected by climate change.
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亚马逊东南部树木的光合量子效率可能已经受到气候变化的影响。
DOI：
10.1111/pce.13770
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发表时间：
2021
期刊：
影响因子：
--
通讯作者：
Tiwari R
中科院分区：
文献类型：
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作者：
Tiwari R
由于气候变化，热带森林正在经历前所未有的高温条件，这可能限制它们的光合作用。我们研究了南亚马逊雨林地区光合作用的高温敏感性，那里记录了热带地区最高温度和最迅速变暖的一些记录。利用不同热胁迫水平下的叶片，测定了7种优势树种光系统II的量子产量（Fv/Fm）。t50是指fv / fm为最大值的一半时的温度。t5定义为断点温度，在此温度开始fv / fm下降。快速变暖的南亚马逊地区的叶片耐热性是全球森林树种中最高的。t50和t5值在不同种间存在差异，其中位于中层的阿麻瓜（Amaioua guianensis）表现出较高的t50和t5值。虽然采样物种的t50值比亚马逊南部最高气温高几度，但在当前最高气温下，一些物种的t50值现在已经超过了。
Tropical forests are experiencing unprecedented high‐temperature conditions due to climate change that could limit their photosynthetic functions. We studied the high‐temperature sensitivity of photosynthesis in a rainforest site in southern Amazonia, where some of the highest temperatures and most rapid warming in the Tropics have been recorded. The quantum yield (Fv/Fm) of photosystem II was measured in seven dominant tree species using leaf discs exposed to varying levels of heat stress.T50was calculated as the temperature at whichFv/Fmwas half the maximum value.T5is defined as the breakpoint temperature, at whichFv/Fmdecline was initiated. Leaf thermotolerance in the rapidly warming southern Amazonia was the highest recorded for forest tree species globally.T50andT5varied between species, with one mid‐storey species,Amaioua guianensis, exhibiting particularly highT50andT5values. While theT50values of the species sampled were several degrees above the maximum air temperatures experienced in southern Amazonia, theT5values of several species are now exceeded under present‐day maximum air temperatures.