Does free-Air carbon dioxide enrichment affect photochemical energy use by evergreen trees in different Seasons? A chlorophyll fluorescence study of mature loblolly pine
Does free-Air carbon dioxide enrichment affect photochemical energy use by evergreen trees in different Seasons? A chlorophyll fluorescence study of mature loblolly pine
复制标题
自由空气二氧化碳富集是否会影响不同季节常绿树木的光化学能量利用？
DOI：
10.1104/pp.120.4.1183
复制
发表时间：
1999
期刊：
影响因子：
7.4
通讯作者：
Long
中科院分区：
文献类型：
--
作者：
Hymus;Ellsworth;Baker;Long
先前关于在高CO(2)环境下生长对光合机构能量分配影响的研究产生了相互矛盾的结果。我们提出并验证了这样一个假设：当对同化物的需求高时，CO(2)的升高会增加光化学能的使用，而当需求低时，则会减少使用。在成熟的12 m火炬松（Pinus taeda L.）林顶针叶上测量了叶绿素a荧光和叶片气体交换的变化。树木暴露于环境CO(2)或环境+ 20 Pa CO(2)中，利用自由空气CO(2)富集。在4月和8月，增加的CO(2)增加了幼苗的生长期、光饱和光合作用和线性电子传递期。在11月，当生长停止但温度仍然适中时，CO(2)处理对线性电子传递没有显著影响。在2月份，当低温可能抑制易位时，CO(2)处理导致线性电子传递显著降低。这与将针叶转移到阴凉处的最大光系统II效率恢复较慢相吻合，表明CO(2)升高的生长诱导了更持久的光抑制。在CO(2)浓度升高的情况下，线性电子输运的夏季增加和冬季减少都是由于光化学猝灭的变化，而不是光系统II天线内能量传递效率的变化。除碳代谢外，没有证据表明CO(2)对光化学能量汇有任何影响。我们的研究结果表明，CO(2)升高可能会增加冬季胁迫对常绿叶片的影响。
Previous studies of the effects of growth at elevated CO(2) on energy partitioning in the photosynthetic apparatus have produced conflicting results. The hypothesis was developed and tested that elevated CO(2) increases photochemical energy use when there is a high demand for assimilates and decreases usage when demand is low. Modulated chlorophyll a fluorescence and leaf gas exchange were measured on needles at the top of a mature, 12-m loblolly pine (Pinus taeda L.) forest. Trees were exposed to ambient CO(2) or ambient plus 20 Pa CO(2) using free-air CO(2) enrichment. During April and August, periods of shoot growth, light-saturated photosynthesis and linear electron transport were increased by elevated CO(2). In November, when growth had ceased but temperatures were still moderate, CO(2) treatment had no significant effect on linear electron transport. In February, when low temperatures were likely to inhibit translocation, CO(2) treatment caused a significant decrease in linear electron transport. This coincided with a slower recovery of the maximum photosystem II efficiency on transfer of needles to the shade, indicating that growth in elevated CO(2) induced a more persistent photoinhibition. Both the summer increase and the winter decrease in linear electron transport in elevated CO(2) resulted from a change in photochemical quenching, not in the efficiency of energy transfer within the photosystem II antenna. There was no evidence of any effect of CO(2) on photochemical energy sinks other than carbon metabolism. Our results suggest that elevated CO(2) may increase the effects of winter stress on evergreen foliage.