Will rising CO2 protect plants from the midday sun? A study of photoinhibition of Quercus myrtifolia in a scrub‐oak community in two seasons
Will rising CO2 protect plants from the midday sun? A study of photoinhibition of Quercus myrtifolia in a scrub‐oak community in two seasons
复制标题
二氧化碳浓度上升会保护植物免受正午阳光的影响吗？两个季节灌木橡树群落中栎树光抑制的研究
DOI：
10.1046/j.1365-3040.2001.00792.x
复制
发表时间：
2001
影响因子：
7.3
通讯作者：
S. Long
中科院分区：
文献类型：
--
作者：
G. Hymus;P. Dijkstra;N. Baker;B. Drake;S. Long
在很大一部分光周期内，冠层上部叶片吸收的光能使光合作用饱和，超过光系统II （jpsii）光饱和线性电子流的能量需求，从而产生光抑制。从光饱和光合作用对大气co2分压（pco2）升高响应的理论考虑可以预测，在光饱和光合作用rubisco限制的地方，pco2的增加将刺激jpsii。因此，吸收的量子光化学耗散的比例将增加，光合作用的光抑制潜力将降低。这是通过测量猕猴桃的调制叶绿素a荧光来验证的。在美国佛罗里达州梅里特岛，在目前的环境或升高的（环境+35 Pa） CO 2环境中，在露天舱内生长。在春夏季，光饱和光合作用在当前环境co2下受到rubisco限制。与理论预测一致，春季co2浓度升高使jpsii升高，光抑制减弱。在夏季，当生长基本停止时，最大核酮糖1,5二磷酸饱和羧化能力（vcmax）的同化性降低消除了春季看到的jpsii的刺激，并且在pco2升高时光抑制增强。综上所述，对于田间生长的猕猴桃，co2浓度升高对jpsii和光抑制的影响可预测地反映出光合适应的季节差异。
Over a large part of the photoperiod, light energy absorbed by upper canopy leaves saturates photosynthesis and exceeds the energetic requirements for light-saturated linear electron flow through photosystem II ( J PSII ), so that photoinhibition results. From a theoretical consideration of the response of light-saturated photosynthesis to elevated atmospheric CO 2 partial pressure ( p CO 2 ) it may be predicted that, where light-saturated photosynthesis is Rubisco-limited, an increase in p CO 2 will stimulate J PSII . Therefore, the proportion of absorbed quanta dissipated photochemically will increase and the potential for photoinhibition of photosynthesis will decrease. This was tested by measuring modulated chlorophyll a fluorescence from Quercus myrtifolia Willd. growing in the field in open-top chambers, at either current ambient or elevated (ambient +35 Pa) p CO 2 on Merritt Island, Florida, USA. During spring and summer, light-saturated photosynthesis at current ambient p CO 2 was Rubisco-limited. Consistent with theoretical prediction, J PSII was increased and photoinhibition decreased by elevated p CO 2 in spring. In the summer, when growth had largely ceased, an acclimatory decrease in the maximum Ribulose 1,5 bisphosphate saturated carboxylation capacity ( V c max ) removed the stimulation of J PSII seen in the spring, and photoinhibition was increased in elevated p CO 2 . It is concluded that, for Q. myrtifolia growing in the field, the effects of elevated p CO 2 on J PSII and photoinhibition will reflect seasonal differences in photosynthetic acclimation to elevated p CO 2 in a predictable manner.