Zha Tian-Shan, Kellomäki Seppo, Wang Kai-Yun, Ryyppö Aija
Faculty of Forestry, University of Joensuu, P.O. Box 111, FIN-80101 Joensuu, Finland.
Tree Physiol. 2005 Jan;25(1):49-56. doi: 10.1093/treephys/25.1.49.
Stem respiration in 20-year-old Scots pine (Pinus sylvestris L.) trees was examined following 5 years of exposure to ambient conditions (CON), elevated atmospheric carbon dioxide concentration ([CO2]) (ambient + 350 micromol mol(-1), (EC)), elevated temperature (ambient + 2-6 degrees C, (ET)) or a combination of elevated [CO2] and elevated temperature (ECT). Stem respiration varied seasonally regardless of the treatment and displayed a similar trend to temperature, with maximum rates occurring around Day 190 in summer and minimum rates in winter. Respiration normalized to 15 degrees C (R15) was higher in the growing season than in the non-growing season, whereas the temperature coefficient (Q10) was lower in the growing season. Annually averaged R15 was 0.36, 0.43, 0.40 and 0.44 micromol m(-2) s(-1) under CON, EC, ET and ECT conditions, respectively, whereas the corresponding values for total stem respiration were 6.55, 7.69, 7.50 and 7.90 mol m(-2) year(-1). The EC, ET and ECT treatments increased R15 by 18, 11 and 22%, respectively, relative to CON, and increased the modeled annual total stem respiration by 18, 15 and 21%. The increase in modeled annual stem respiration under EC and ECT conditions was caused mainly by higher maintenance respiration (22 and 25%, respectively, whereas the increase in growth respiration was 9 and 12%). Growth respiration was unaltered by ET. The treatments did not significantly affect the respiratory response to stem temperature; the mean Q10 value was 2.04, 2.10, 1.99 and 2.12 in the CON, EC, ET and ECT treatments, respectively. It is suggested that the increase in stem respiration was partly a result of the increased growth rate. We conclude that elevated [CO2] increased the maintenance component of respiration more than the growth component.
在对20年生欧洲赤松（Pinus sylvestris L.）树进行5年的环境条件（CON）、高浓度大气二氧化碳（[CO2]）（环境浓度 + 350 μmol mol⁻¹，（EC））、高温（环境温度 + 2 - 6℃，（ET））或高浓度[CO2]与高温组合（ECT）处理后，对其树干呼吸进行了研究。无论处理方式如何，树干呼吸都随季节变化，且与温度呈现相似趋势，夏季约在第190天出现最高速率，冬季出现最低速率。生长季中归一化至15℃的呼吸速率（R15）高于非生长季，而温度系数（Q10）在生长季较低。在CON、EC、ET和ECT条件下，年平均R15分别为0.36、0.43、0.40和0.44 μmol m⁻² s⁻¹，而树干总呼吸的相应值分别为6.55、7.69、7.50和7.90 mol m⁻² 年⁻¹。与CON相比，EC、ET和ECT处理使R15分别增加了18%、11%和22%，并使模拟的年树干总呼吸增加了18%、15%和21%。EC和ECT条件下模拟的年树干呼吸增加主要是由于维持呼吸增加（分别为22%和25%，而生长呼吸增加分别为9%和12%）。ET对生长呼吸没有影响。这些处理对树干呼吸对温度的响应没有显著影响；CON、EC、ET和ECT处理中的平均Q10值分别为2.04、2.10、1.99和2.12。研究表明，树干呼吸增加部分是生长速率增加的结果。我们得出结论，高浓度[CO2]增加呼吸的维持部分多于生长部分。
