Physiological responses of Abies faxoniana seedlings to different non-growing-season temperatures as revealed by reciprocal transplantations at two contrasting altitudes

Detailed information on plants' responses to varying temperature conditions will be useful when assessing the potential effects of climate change. We conducted reciprocal transplantations in Abies faxoniana Rehd. et Wils. to detect responses of seedlings to different winter (non-growing-season) temperatures in the Wanglang National Nature Reserve, China. Winter temperature variation might alter nitrogen allocation between 1-year-old leaves and branchlets. In leaves, coupling acclimation between photosynthesis potential (evident in pigment content and composition and carbon isotope composition ( δ 13 C)) and adversity tolerance (detectable in peroxidase activity, malondialdehyde content, and nonstructural carbohydrate composition) to winter temperature variation was documented, whereas in branchlets, warming winter did not result in a δ 13 C-discriminative respiration process at tissue level. Although the experiment included only a short winter period, warming winter was found to pose a negative influence (decreased storage and increased leaf thickness) on A. faxoniana seedlings of subalpine forest understory. As both genetic adaptation and phenotypic plasticity could be responsible for such physiological variation, a detailed altitudinal investigation and a long-term experiment on A. faxoniana seedlings are needed to properly assess their responses to climate change.