Temperature response of parameters of a biochemically based model of photosynthesis. I. Seasonal changes in mature maritime pine (Pinus pinaster Ait.)
Temperature response of parameters of a biochemically based model of photosynthesis. I. Seasonal changes in mature maritime pine (Pinus pinaster Ait.)
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DOI：
10.1046/j.1365-3040.2002.00890.x
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发表时间：
2002-09
影响因子：
7.3
通讯作者：
B. Medlyn;D. Loustau;S. Delzon
中科院分区：
文献类型：
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作者：
B. Medlyn;D. Loustau;S. Delzon
植物过程对温度的反应可能会根据它们被测量的时间尺度而变化。在这项研究中，光合作用的短期和季节响应温度进行了研究。对法国和摩洛哥两个种源的成熟海松（PinuspinasterAit.）光合作用温度响应的季节变化进行了野外研究。在1年的时间内，每2个月进行一次测量，并用于参数化光合作用的机械模型。温度响应的最大Rubisco活性，V cmax，和潜在的电子传递速率，J最大值，得到每个测量期间，气孔导度的响应，g s，水蒸气压赤字（VPD）。25 ° C时的Vcmax和Jmax的绝对值与针叶含氮量、N面积有关。N面积，因此V cmax和J max，与平均最低温度在一个月前测量呈负相关。在25 ° C时，Jmax：VCmax的比值在1~1.7之间变化，但没有表现出任何季节性趋势。V cmax的相对温度响应也没有任何季节性趋势，在整个实验中，其活化能Ha约为57 kJ mol − 1。在整个实验过程中，J max的活化能也接近恒定，平均为39 kJ mol-1。法国种源的最适温度与前一天的最高温度呈正相关，而摩洛哥种源的最适温度与前一天的最高温度无相关性。G-S对VPD的响应也随季节变化，冬季气孔关闭更强。综上所述，这些结果意味着随着T prev的增加，光合作用温度响应曲线向下平移，并且夏季和冬季之间光合作用的最佳温度偏移5 - 10 ° C。这些结果表明，光合作用的短期温度响应在季节基础上变化显着。
Responses of plant processes to temperature may vary according to the time scale on which they are measured. In this study, both short-term and seasonal responses of photosynthesis to temperature were examined. A field study of seasonal changes in the temperature response of photosynthesis was conducted on two provenances, French and Moroccan, of mature maritime pine ( Pinus pinaster Ait.). Measurements were made every 2 months over a 1-year period and used to parameterize a mechanistic model of photosynthesis. Temperature responses of maximum Rubisco activity, V cmax , and potential electron transport rate, J max , were obtained for each measurement period, as was the response of stomatal conductance, g s , to water vapour pressure deficit (VPD). Absolute values of V cmax and J max at 25 ° C were related to needle nitrogen content, N area. N area , and thus V cmax and J max , were negatively correlated with the mean minimum temperature in the month preceding measurements. The ratio of J max : V cmax at 25 ° C varied between 1 and 1·7 but did not show any seasonal trend. Nor was there any seasonal trend in the relative temperature response of V cmax , which had an activation energy H a of approximately 57 kJ mol − 1 throughout the experiment. The activation energy of J max was also close to constant throughout the experiment, averaging 39 kJ mol − 1 . For the French provenance, the optimal temperature of J max was positively correlated with the maximum temperature of the previous day, but no such correlation was found for the Moroccan provenance. The response of g s to VPD also varied seasonally, with much stronger stomatal closure in winter months. Taken together, these results implied a translational shift downwards of the photosynthetic temperature response curve with increasing T prev , and a shift in the temperature optimum of photosynthesis of 5‐10 ° C between summer and winter. These results illustrate that the short-term temperature response of photosynthesis varies significantly on a seasonal basis.