State Key Laboratory of Tree Genetics and Breeding, Key Laboratory of Tree Breeding and Cultivation of State Forestry Administration, Research Institute of Forestry, Chinese Academy of Forestry, Beijing, China.
Swiss Federal Research Institute WSL, CH-8903 Birmensdorf, Switzerland.
Sci Rep. 2017 Feb 14;7:42462. doi: 10.1038/srep42462.
Drought potentially affects carbon balance and growth of trees, but little is known to what extent soil plays a role in the trade-off between carbon gain and growth investment. In the present study, we analyzed leaf non-structural carbohydrates (NSC) as an indicator of the balance of photosynthetic carbon gain and carbon use, as well as growth of European beech (Fagus sylvatica L.) saplings, which were grown on two different soil types (calcareous and acidic) in model ecosystems and subjected to a severe summer drought. Our results showed that drought led in general to increased total NSC concentrations and to decreased growth rate, and drought reduced shoot and stem growth of plants in acidic soil rather than in calcareous soil. This result indicated that soil type modulated the carbon trade-off between net leaf carbon gain and carbon investment to growth. In drought-stressed trees, leaf starch concentration and growth correlated negatively whereas soluble sugar:starch ratio and growth correlated positively, which may contribute to a better understanding of growth regulation under drought conditions. Our results emphasize the role of soil in determining the trade-off between the balance of carbon gain and carbon use on the leaf level and growth under stress (e.g. drought).
干旱可能会影响树木的碳平衡和生长，但对于土壤在碳收益和生长投资之间的权衡中扮演何种角色，我们知之甚少。在本研究中，我们分析了叶片非结构性碳水化合物（NSC），作为光合作用碳收益和碳利用平衡以及欧洲山毛榉（Fagus sylvatica L.）幼苗生长的指标，这些幼苗生长在模型生态系统中的两种不同土壤类型（钙质和酸性）上，并经历了严重的夏季干旱。我们的结果表明，干旱通常会导致总 NSC 浓度增加和生长速度降低，而且干旱会减少酸性土壤中而不是钙质土壤中植物的新梢和茎生长。这一结果表明，土壤类型调节了净叶碳收益和碳投资对生长的碳权衡。在受干旱胁迫的树木中，叶片淀粉浓度与生长呈负相关，而可溶性糖：淀粉比与生长呈正相关，这可能有助于更好地理解干旱条件下的生长调控。我们的结果强调了土壤在决定叶片水平上碳收益和碳利用平衡以及胁迫（如干旱）下生长之间的权衡中的作用。
