Temperature acclimation of leaf respiration (R) is an important determinant of ecosystem responses to temperature and the magnitude of temperature-CO₂ feedbacks as climate warms. Yet, the extent to which temperature acclimation of R exhibits a common pattern across different growth conditions, ecosystems, and plant functional types remains unclear. Here, we measured the short-term temperature response of R at six time points over a 10-month period in two coastal wetland species (Avicennia germinans [C₃ mangrove] and Spartina alterniflora [C₄ marsh grass]) growing under ambient and experimentally warmed temperatures at two sites in a marsh–mangrove ecotone. Leaf nitrogen (N) was determined on a subsample of leaves to explore potential coupling of R and N. We hypothesized that both species would reduce R at 25°C (R²⁵) and the short-term temperature sensitivity of R (Q₁₀) as air temperature (T_air) increased across seasons, but the decline would be stronger in Avicennia than in Spartina. For each species, we hypothesized that seasonal temperature acclimation of R would be equivalent in plants grown under ambient and warmed temperatures, demonstrating convergent acclimation. Surprisingly, Avicennia generally increased R²⁵ with increasing growth temperature, although the Q₁₀ declined as seasonal temperatures increased and did so consistently across sites and treatments. Weak temperature acclimation resulted in reduced homeostasis of R in Avicennia. Spartina reduced R²⁵ and the Q₁₀ as seasonal temperatures increased. In Spartina, seasonal temperature acclimation was largely consistent across sites and treatments resulting in greater respiratory homeostasis. We conclude that co-occurring coastal wetland species may show contrasting patterns of respiratory temperature acclimation. Nonetheless, leaf N scaled positively with R²⁵ in both species, highlighting the importance of leaf N in predicting respiratory capacity across a range of growth temperatures. The patterns of respiratory temperature acclimation shown here may improve the predictions of temperature controls of CO₂ fluxes in coastal wetlands.

中文翻译：

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滨海湿地交错带沼泽和红树林植被叶片呼吸的温度驯化差异

随着气候变暖，叶片呼吸的温度驯化 ( R ) 是生态系统对温度响应和温度-CO ₂反馈幅度的重要决定因素。然而，R 的温度适应在不同的生长条件、生态系统和植物功能类型中表现出共同模式的程度仍不清楚。在这里，我们测量的短期温度的响应ř在六个时间点在10个月期间两个沿海湿物种（白骨germinans [C ₃红树]和互花米草[C ₄沼泽草]）在沼泽-红树林交错带的两个地点在环境温度和实验升温下生长。叶片氮（N）测定叶子上的一个子样本探索的电位耦合ř和N.我们假设，这两个物种将减少ř在25°C（- [R ²⁵）和短期温度敏感性- [R （Q ₁₀）由于气温 ( T _air ) 随季节增加，但Avicennia的下降幅度比Spartina的下降幅度更大。对于每个物种，我们假设R 的季节性温度驯化在环境温度和温暖温度下生长的植物中将是等效的，表明收敛性驯化。令人惊讶的是，Avicennia通常会随着生长温度的升高而增加R ²⁵，尽管Q ₁₀随着季节性温度的升高而下降，并且在不同地点和处理方法之间保持一致。弱温度驯化导致的降低的稳态ř在白骨。随着季节性温度升高，Spartina降低了R ²⁵和Q ₁₀。在斯巴达，季节性温度适应在不同地点和治疗方法之间基本一致，从而导致更大的呼吸稳态。我们得出结论，共同发生的沿海湿地物种可能表现出对比鲜明的呼吸温度适应模式。尽管如此，在这两个物种中，叶子 N 与R ²⁵呈正比例，突出了叶子 N 在预测一系列生长温度下呼吸能力的重要性。这里显示的呼吸温度适应模式可能会改进对沿海湿地CO ₂通量的温度控制的预测。