Wayne P M, Reekie E G, Bazzaz F A
Department of Organismic and Evolutionary Biology, Harvard University, 16 Divinity Ave, Cambridge, MA 02138, USA fax: +1-617-495-9300; e-mail:
Department of Biology, Acadia University, Wolfville, Nova Scotia, BOP 1XO, Canada, , , , , , CA.
Oecologia. 1998 Apr;114(3):335-342. doi: 10.1007/s004420050455.
Despite predictions that both atmospheric CO concentrations and air temperature will rise together, very limited data are currently available to assess the possible interactive effects of these two global change factors on temperate forest tree species. Using yellow birch (Betula alleghaniensis) as a model species, we studied how elevated CO (800 vs. 400 μl l) influences seedling growth and physiological responses to a 5°C increase in summer air temperatures (31/26 vs. 26/21°C day/night), and how both elevated CO and air temperature during the growing season influence seedling ability to survive freezing stress during the winter dormant season. Our results show that while increased temperature decreases seedling growth, temperature-induced growth reductions are significantly lower at elevated CO concentrations (43% vs. 73%). The amelioration of high-temperature stress was related to CO-induced reductions in both whole-shoot dark respiration and transpiration. Our results also show that increased summer air temperature, and to a lesser degree CO concentration, make dormant winter buds less susceptible to freezing stress. We show the relevance of these results to models used to predict how climate change will influence future forest species distribution and productivity, without considering the direct or interactive effects of CO
尽管有预测称大气中二氧化碳浓度和气温将同时上升，但目前可用于评估这两个全球变化因素对温带森林树种可能产生的交互作用的数据非常有限。我们以黄桦（Betula alleghaniensis）作为模式物种，研究了高浓度二氧化碳（800 μl·l 与 400 μl·l 相比）如何影响幼苗生长以及对夏季气温升高 5°C（白天/夜间为 31/26°C 与 26/21°C 相比）的生理反应，以及生长季节的高浓度二氧化碳和气温如何影响幼苗在冬季休眠季节抵御冻害的能力。我们的结果表明，虽然气温升高会降低幼苗生长，但在高浓度二氧化碳条件下，温度引起的生长减少幅度显著更低（分别为 43%和 73%）。高温胁迫的缓解与二氧化碳诱导的全株暗呼吸和蒸腾作用降低有关。我们的结果还表明，夏季气温升高以及在较小程度上二氧化碳浓度升高，会使休眠的冬芽对冻害的敏感性降低。我们展示了这些结果与用于预测气候变化将如何影响未来森林物种分布和生产力的模型的相关性，而无需考虑二氧化碳的直接或交互作用
