Zhejiang Provincial Key Laboratory of Plant Evolutionary Ecology and Conservation, Taizhou University, Taizhou 318000, China; College of Nature Conservation, Beijing Forestry University, Beijing 100083, China; Forest dynamics, Swiss Federal Research Institute WSL, Zuercherstrasse 111, CH-8903 Birmensdorf, Switzerland.
Zhejiang Provincial Key Laboratory of Plant Evolutionary Ecology and Conservation, Taizhou University, Taizhou 318000, China; Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110164, China; Forest dynamics, Swiss Federal Research Institute WSL, Zuercherstrasse 111, CH-8903 Birmensdorf, Switzerland.
Sci Total Environ. 2018 May 1;622-623:1463-1475. doi: 10.1016/j.scitotenv.2017.12.070. Epub 2017 Dec 19.
Elevation is a complex environmental factor altering temperature, light, moisture and soil nutrient availability, and thus may affect plant growth and physiology. Such effects of elevation may also depend on seasons. Along an elevational gradient of the Balang Mountain, southwestern China, we sampled soil and 2-year old leaves, 2-year old shoots, stem sapwood and fine roots (diameter<5mm) of Quercus aquifolioides at 2843, 2978, 3159, 3327, 3441 and 3589m a.s.l. in both summer and winter. In summer, the concentrations of tissue non-structural carbohydrates (NSC) did not decrease with increasing elevation, suggesting that the carbon supply is sufficient for plant growth at high altitude in the growing season. The concentration of NSC in fine roots decreased with elevation in winter, and the mean concentration of NSC across tissues in a whole plant showed no significant difference between the two sampling seasons, suggesting that the direction of NSC reallocation among plant tissues changed with season. During the growing season, NSC transferred from leaves to other tissues, and in winter NSC stored in roots transferred from roots to aboveground tissues. Available soil N increased with elevation, but total N concentrations in plant tissues did not show any clear elevational pattern. Both available soil P and total P concentrations in all plant tissues decreased with increasing elevation. Thus, tissue N:P ratio increased with elevation, suggesting that P may become a limiting element for plant growth at high elevation. The present study suggests that the upper limit of Q. aquifolioides on Balang Mountain may be co-determined by winter root NSC storage and P availability. Our results contribute to better understanding of the mechanisms for plants' upper limit formation.
海拔是一个复杂的环境因素，会改变温度、光照、水分和土壤养分供应，从而影响植物的生长和生理。海拔对植物的这些影响可能还取决于季节。在中国西南部的巴郎山，我们在夏季和冬季分别在 2843、2978、3159、3327、3441 和 3589 米海拔处采集了锐齿栎的土壤和 2 年生叶片、2 年生嫩枝、茎边材和直径<5mm 的细根。在夏季，组织非结构性碳水化合物（NSC）的浓度并没有随着海拔的升高而降低，这表明在生长季节高海拔地区的碳供应足以支持植物的生长。冬季细根中 NSC 的浓度随海拔升高而降低，整个植物组织中 NSC 的平均浓度在两个采样季节之间没有显著差异，这表明 NSC 在植物组织之间的再分配方向随季节而变化。在生长季节，NSC 从叶片转移到其他组织，而在冬季，储存在根部的 NSC 从根部转移到地上组织。土壤有效氮随海拔升高而增加，但植物组织中总氮浓度没有表现出明显的海拔模式。所有植物组织中的土壤有效磷和总磷浓度都随海拔升高而降低。因此，组织氮磷比随海拔升高而增加，这表明在高海拔地区磷可能成为植物生长的限制因素。本研究表明，巴郎山锐齿栎的上限可能由冬季根 NSC 储存和 P 供应共同决定。我们的研究结果有助于更好地理解植物上限形成的机制。
