油松叶功能性状分布特征及其控制因素

植物叶功能性状能够直接或间接反应植物对环境的适应策略,这种适应策略会间接影响植物的生长、繁殖和生存。目前已有大量关于植物叶功能性状与环境间关系的研究,但这些研究多使用性状平均值代替物种,忽略了性状的种内变化。油松是我国重要的造林树种,对我国陆地生态系统起着重要的作用,研究其叶功能性状与环境的关系有助于更好的的理解种内功能性状与环境间的关系。于2014年6—9月对辽宁、内蒙、北京、山西、陕西、宁夏、青海等地天然油松进行采样并对其重要的8个叶功能性状的分布特征及主控环境因子进行了研究,结果表明:1)油松各叶性状值存在较大的种内变异系数(4.82%—25.85%),除1年生叶碳含量(LCC)油松各叶功能性状值在不同研究地点间差异显著(P0.05);2)油松叶长(LL)、叶厚(LT)、比叶面积(SLA)、气孔密度(SD)、叶氮含量(LNC)存在较弱的经度格局,LT、SD、LNC存在较弱的纬度格局(0.05R~20.3),水热条件的变化以及较大的局部效应是造成这种格局的可能原因;3)控制油松各叶性状分布的主要环境因子各不相同,其中LL主要受到年平均降水量和海拔高度的影响;LT主要受到年均温和土壤体积含水率的影响;SLA主要受到年平均降水量和土壤氮含量的影响;叶干物质含量(LDMC)主要受到水因子的影响;SD主要受到海拔高度的影响;LNC主要受到海拔和水因子的影响;叶磷含量(LPC)主要受到土壤磷含量的影响。

Leaf functional trait distribution and controlling factors of Pinus tabuliformis

Leaf functional traits can directly or indirectly reflect the adaptation strategy of plants to the environment, influencing their survival, growth, and reproduction. Until recently, there have been many studies on the relationship between leaf functional traits and environment, but most have used the single or mean value of the traits to represent one species, ignoring considerable intraspecific variations.Pinus tabuliformis is one of the main afforestation tree species in China, playing an important role in terrestrial ecosystems. Thus, the relationship between the leaf functional traits of P. tabuliformis and environmental factors could elucidate the relationship between intraspecific variations and environmental factors. The results of this study could provide a theoretical basis for better protection, development, and utilization of P. tabuliformis forests under global climate change. In the present paper, we analyzed the environment factors and distribution of eight leaf functional traits of P. tabuliformis in its natural distribution range, including leaf length (LL), leaf thickness (LT), specific leaf area (SLA), leaf dry matter content (LDMC), stomatal density (SD), leaf nitrogen concentration (LNC), leaf phosphorus concentration (LPC), and leaf carbon concentration (LCC), from leaves collected in Inner Mongolia, Liaoning, Beijing, Shanxi, Shaanxi, Ningxia and Qinghai Provinces, from June to September 2014. The results showed that 1) The leaf functional traits of P. tabuliformis showed significant intraspecific variations, and the variation coefficient was between 4.82% and 25.85%. The traits, except the LCC of annual leaves, showed significant differences between different research sites (P < 0.05), the intraspecific variation of LPC was the highest (23.29% for annual leaves and 25.85% for perennial leaves), and the intraspecific variation of LDMC was the lowest (5.91% for annual leaves and 4.82% for perennial leaves). 2) There were significant correlations between the leaf trait and the longitude and latitude (P < 0.05). LL, LT, SLA, SD, and LNC of P. tabuliformis leaves exhibited a weak longitude distribution pattern, and LT, SD, and LNC exhibited a weak latitude distribution pattern. The combined effect of changing hydrothermal conditions along longitude and latitude and strong local effects could contribute to the formation of these patterns. There was also significant variation among different individuals at the same site, suggesting large local effects, which could weaken the longitude and latitude distribution pattern on the large scale, leading to a small R value (0.05 < R² < 0.3). 3) The pattern of leaf functional traits was affected by various environmental factors, and each leaf trait of P. tabuliformis was affected by several factors. Further, the main controlling factors of different traits were different; the controlling factors of annual and perennial leaves were different in some traits. In the present study, we found that the LL was mainly affected by the mean annual precipitation and altitude, LT was mainly affected by the mean annual temperature and volumetric soil water content, SLA was mainly affected by the mean annual precipitation and soil nitrogen content, LDMC was mainly affected by water factors, SD was mainly affected by altitude, LNC was mainly affected by altitude and water factors, and LPC was mainly affected by soil phosphorus content.