[Effects of latitudinal transplanting on temperature sensitivity of leaf dark respiration for Larix gmelinii.]

Exploring the temperature sensitivity of leaf dark respiration is of significance for understanding forest carbon cycling and its response to climate change. However, its intra-specific variability and seasonality are not clear yet. In this study, we measured the temperature sensitivity coefficient (Q₁₀) of leaf dark respiration for Dahurian larch (Larix gmelinii) that were transplanted from four latitudinal sites (i.e., Tahe, Songling, Heihe, and Dailing) in a common garden. Our specific aims were to explore the seasonal dynamics of Q₁₀ and compare differences in Q₁₀ among the indivi-duals from the four latitudinal sites. The results showed that the Q₁₀ for the four sites exhibited similar seasonal trend, with the maximum Q₁₀ in the middle growing season. The inter-site difference in Q₁₀ was significant, ranging from (1.48±0.01) to (2.15±0.03). Furthermore, the inter-site difference showed the same pattern across the whole growing season, i.e., the warmer and lower latitudinal sites, the higher Q₁₀. The Q₁₀ was significantly and positively correlated with foliar nitrogen concentration and soluble sugar concentration, and mean annual temperature and mean annual precipitation in the transplanting sites. These findings suggested that the inter-site variation in Q₁₀ and its seasonality could be mainly attributed to the foliar nutrient concentration and adaptation of trees to the climatic conditions of the transplanting sites, which should be considered in modeling and predicting responses of forest carbon cycling to climate change.