Inhibition and acclimation of C(3) photosynthesis to moderate heat: a perspective from thermally contrasting genotypes of Acer rubrum (red maple).
Inhibition and acclimation of C(3) photosynthesis to moderate heat: a perspective from thermally contrasting genotypes of Acer rubrum (red maple).
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DOI：
10.1093/treephys/27.8.1083
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发表时间：
2007-08
期刊：
影响因子：
4
通讯作者：
D. Weston;W. Bauerle
中科院分区：
文献类型：
--
作者：
D. Weston;W. Bauerle
研究了中度高温对两种红槭无性系基因型生长和光合作用的影响，最初收集自美国佛罗里达和明尼苏达的热对比生境，并且在园艺贸易中分别以对热的敏感性和不敏感性而闻名。在普通花园和温暖的温室条件下（33/25摄氏度的昼夜温度），佛罗里达基因型比明尼苏达基因型表现出更多的生长。为了确定与该响应相关的生理参数，使植物适应环境温度（27/25 ℃）或适度升高的温度（33/25 ℃）21天，然后在25至48 ℃的温度下测量净光合作用。对环境驯化植物的气体交换和叶绿素a荧光的活体测量表明，与明尼苏达基因型相比，佛罗里达基因型保持了更高的光合速率，更高的气孔导度，更开放的PSII反应中心，PSII量子产率较高，光系统II的量子需求较低在整个测量温度范围内，每摩尔固定的CO（2）（phi（CO（2）的（phi（PSII））。当这两种基因型在33/25摄氏度下驯化并在33摄氏度下测量时，净光合作用对计算的细胞间CO（2）浓度的响应分析表明，在明尼苏达基因型中Rubisco羧化的最大速率（V（cmax））比佛罗里达基因型对升高的温度的响应降低得更多。此外，在33 ℃下，光呼吸条件下明尼苏达州植物的phi（PSII）/phi（CO（2））明显较高，但在非光呼吸条件下与佛罗里达植物相似。结果表明，与明尼苏达基因型相比，佛罗里达基因型在33/25摄氏度下更高的净光合速率可能是几种机制的结果，包括维持更高的V（cmax）和更有效的PSII量子需求每摩尔固定的CO（2），这可能是较低的光呼吸的结果。
Effects of moderate heat on growth and photosynthesis were investigated in two clonal genotypes of Acer rubrum L., originally collected from the thermally contrasting habitats of Florida and Minnesota, USA, and known in the horticultural trade for sensitivity and insensitivity to heat, respectively. Under both common garden and warm greenhouse conditions (day/night temperature of 33/25 degrees C), the Florida genotype exhibited more growth than the Minnesota genotype. To determine the physiological parameters associated with this response, plants were acclimated to ambient (27/25 degrees C) or moderately elevated (33/25 degrees C) temperatures for 21 days before measurement of net photosynthesis at temperatures ranging from 25 to 48 degrees C. In vivo measurements of gas exchange and chlorophyll a fluorescence of ambient-acclimated plants revealed that, compared with the Minnesota genotype, the Florida genotype maintained a higher photosynthetic rate, higher stomatal conductance, more open PSII reaction centers, a greater PSII quantum yield and a lower quantum requirement for photosystem II (phi(PSII)) per mole of CO(2) fixed (phi(CO(2) )) throughout the measurement temperature range. When both genotypes were acclimated at 33/25 degrees C and measured at 33 degrees C, analysis of the response of net photosynthesis to calculated intercellular CO(2) concentration indicated that the maximal rate of Rubisco carboxylation (V(cmax)) decreased more in the Minnesota genotype than in the Florida genotype in response to elevated temperature. Additionally, phi(PSII)/phi(CO(2) ) at 33 degrees C was markedly higher for Minnesota plants under photorespiratory conditions, but similar to Florida plants under non-photorespiratory conditions. The results indicate that the higher net photosynthetic rate at 33/25 degrees C of the Florida genotype compared with the Minnesota genotype could be a result of several mechanisms, including the maintenance of a higher V(cmax )and a more efficient quantum requirement of PSII per mole of CO(2) fixed, which is likely the result of lower photorespiration.