Abstract A challenge exists in the need to understand plant responses in complex environmental matrixes, such as those predicted by climate change models, being this information essential for species that support important ecosystem functions. A factorial climatic chamber experiment was designed to evaluate the impact of atmospheric CO2 concentration (400 ppm and 700 ppm CO2) in combination with two maximum and minimum temperature ranges (28/13 °C and 32/17 °C) and salinity concentrations (0 and 171 mM NaCl) on the growth and photosynthetic responses of the ecosystem engineer species Spartina maritima. Plants grown at 32/17 °C showed a reduction ∼39% on relative growth rate (RGR) and this was more drastic (i.e. 64%) in those exposed to 700 ppm CO2, which also showed an increment in the percentage of dead tillers regardless of salinity. These reductions were explained by the negative impact on net photosynthetic rate (AN), which decreased with temperature increment, being this reduction more acute at 700 ppm CO2. This response was associated with an augmentation in CO2 diffusion limitations, as indicated the lower stomatal conductance (gs), together with a down-regulation photochemical apparatus efficiency, as indicated the lower electron transport rate (ETR) and energy fluxes derived from Kautsky curves. In addition, the greatest gs drop at 700 ppm CO2, would limit plant ability to cope with temperature excess through evapotranspiration, a fact that could have boosted temperature-triggered damage and, consequently, leaf senescence. Therefore, we can conclude that temperature and atmospheric CO2 increments would compromise the development of S. maritima and consequently the maintaining of its ecosystem functions.

中文翻译：

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了解与气候变化相关的复杂环境矩阵对欧洲沼泽工程物种 Spartina Maritime 的影响

摘要 需要了解复杂环境矩阵中的植物响应存在挑战，例如气候变化模型预测的那些，这是支持重要生态系统功能的物种所必需的信息。因子气候室实验旨在评估大气 CO2 浓度（400 ppm 和 700 ppm CO2）结合两个最高和最低温度范围（28/13 °C 和 32/17 °C）和盐度浓度（0和 171 mM NaCl）对生态系统工程物种 Spartina maritima 的生长和光合反应的影响。在 32/17 °C 下生长的植物的相对生长率 (RGR) 下降了约 39%，而在暴露于 700 ppm CO2 的植物中，这一下降幅度更大（即 64%），这也表明死蘖的百分比有所增加与盐度无关。这些减少的原因是对净光合速率 (AN) 的负面影响，随着温度升高而降低，这种减少在 700 ppm CO2 时更为剧烈。这种反应与 CO2 扩散限制的增加有关，如较低的气孔导度 (gs)，以及下调的光化学装置效率，如较低的电子传输速率 (ETR) 和源自考茨基曲线的能量通量。此外，700 ppm CO2 时的最大 gs 下降将限制植物通过蒸发蒸腾来应对温度过高的能力，这一事实可能会加剧温度触发的损害，从而导致叶片衰老。因此，我们可以得出结论，温度和大气 CO2 的增加会损害 S 的发展。