Temperature acclimation of leaf respiration differs between marsh and mangrove vegetation in a coastal wetland ecotone
Temperature acclimation of leaf respiration differs between marsh and mangrove vegetation in a coastal wetland ecotone
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DOI：
10.1111/gcb.15938
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发表时间：
2021-10
影响因子：
11.6
通讯作者：
Matt Sturchio;Jeff Chieppa;S. Chapman;Gabriela Cañas;Michael J. Aspinwall
中科院分区：
文献类型：
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作者：
Matt Sturchio;Jeff Chieppa;S. Chapman;Gabriela Cañas;Michael J. Aspinwall
随着气候变暖，叶片呼吸(R)的温度适应是生态系统对温度的响应和温度-CO2反馈的大小的重要决定因素。然而，在不同的生长条件、生态系统和植物功能类型中，R的温度驯化在多大程度上表现出共同的模式仍不清楚。在这里，我们测量了两种滨海湿地物种(白骨壤[C3红树林]和互花米草[C4沼泽草])在10个月的6个时间点上的短期温度响应，它们生长在沼泽-红树林交错带的两个地点的环境温度和实验升温温度下。为了探索R和N之间的潜在耦合，我们在叶片的一个子样上测定了叶片氮(N)。我们假设这两个物种在25℃(R25)时都会随着气温(Tair)的增加而降低R(Q10)的短期温度敏感度，但Avicennia的下降幅度会比Spartina更大。对于每个物种，我们假设R的季节性温度驯化与生长在环境温度和温暖温度下的植物相同，表现出收敛驯化。令人惊讶的是，Avicennia通常随着生长温度的升高而增加R25，尽管Q10随着季节温度的增加而下降，并且在不同地点和处理之间保持一致。弱温度驯化导致白骨壤中R的动态平衡降低。随着季节气温的升高，斯巴达纳减少了R25和Q10。在斯巴达纳，季节性温度驯化在不同地点和处理之间基本一致，导致更大的呼吸稳态。我们得出结论，共同出现的滨海湿地物种可能表现出不同的呼吸温度驯化模式。尽管如此，在两个物种中，叶片N与R25呈正相关，突显了叶片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善对滨海湿地CO2通量的温度控制的预测。
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 (Tair) 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.