The effects on Arbutus unedo L. of long‐term exposure to elevated CO2
The effects on Arbutus unedo L. of long‐term exposure to elevated CO2
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长期暴露于高浓度二氧化碳对杨梅的影响
DOI：
10.1111/j.1365-2486.1995.tb00028.x
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发表时间：
1995
影响因子：
11.6
通讯作者：
F. Miglietta
中科院分区：
文献类型：
--
作者：
MICHAEL B. Jones;J. Brown;A. Raschi;F. Miglietta
杨梅是一种硬叶万年青，是地中海沿岸灌丛植被的特征。在意大利，A.在接近天然CO2喷口的地方，大气中二氧化碳的平均浓度约为2200 μmol mol−1。在高浓度和环境CO2浓度下生长的树木之间进行了比较，以测试适应长期暴露于高浓度CO2的证据。在CO2浓度升高条件下形成的叶片气孔密度和气孔指数较低，比叶面积较高，但叶片组织的碳氮比没有变化。气孔导度较低，在高CO2在春季快速增长。在仲夏，在干旱胁迫下，所有叶片的气孔关闭，并在秋季，当压力缓解，叶片的电导率在高浓度和环境CO2增加。在春季，气孔导度的新冲洗的叶片在环境CO2高于叶片在CO2浓度升高，提高瞬时水分利用效率在CO2浓度升高。叶绿素荧光测量表明，CO2浓度升高在仲夏提供了一些保护，以防止光抑制。A/Cicurves分析表明，没有证据表明，无论是向上或向下调节的光合作用在CO2浓度升高。因此，预计A.随着环境CO2浓度的增加，undowill有更高的增长率。
Arbutus unedois a sclerophyllous evergreen, characteristic of Mediterranean coastal scrub vegetation. In Italy, trees ofA. unedohave been found close to natural CO2vents where the mean atmospheric carbon dioxide concentration is about 2200 μmol mol−1. Comparisons were made between trees growing in elevated and ambient CO2concentrations to test for evidence of adaptation to long‐term exposure to elevated CO2. Leaves formed at elevated CO2have a lower stomatal density and stomatal index and higher specific leaf area than those formed at ambient CO2, but there was no change in carbon to nitrogen ratios of the leaf tissue. Stomatal conductance was lower at elevated CO2during rapid growth in the spring. In mid‐summer, under drought stress, stomatal closure of all leaves occurred and in the autumn, when stress was relieved, the conductance of leaves at both elevated and ambient CO2increased. In the spring, the stomatal conductance of the new flush of leaves at ambient CO2was higher than the leaves at elevated CO2, increasing instantaneous water use efficiency at elevated CO2. Chlorophyll fluorescence measurements suggested that elevated CO2provided some protection against photoinhibition in mid‐summer. Analysis ofA/Cicurves showed that there was no evidence of either upward or downward regulation of photosynthesis at elevated CO2. It is therefore anticipated thatA. unedowill have higher growth rates as the ambient CO2concentrations increase.