细叶云南松种实性状变异与地理气象因子的关联

细叶云南松(Pinus yunnanensis var. tenuifolia)是分布于滇、黔、桂交界处的一个云南松变种, 其自然生境独特, 属典型的干热河谷气候, 具有重要的生态、经济价值。该研究以分布于南盘江-红水河流域沿线的8个细叶云南松天然种群为材料, 采用描述性统计及巢式方差分析比较种群间及种群内种实性状差异, 运用Pearson相关及典型相关分析探究种实性状与地理气象因子间的相关性, 最后对种群进行主成分聚类和Mantel检验, 揭示其种实性状地理变异模式。结果显示: 细叶云南松11个种实性状在种群间和种群内都存在极显著差异(p < 0.001), 变异丰富。种实性状以种群内变异为主(平均表型分化系数V_ST = 18.65%), 球果性状种群间分化(24.22%-39.88%)高于种子及种翅性状(4.14%-13.80%), 表明球果性状受到更强的环境选择。尽管部分相关系数未达显著水平, 但整体上种实性状与经纬度、年平均气温呈正相关关系, 与相对湿度、年降水量呈负相关关系, 表明细叶云南松种实性状受到地理隔离、湿度和温度的协同选择作用, 使其能较好适应干热环境。主成分聚类将参试种群划分为3类, 位于东部的罗甸伍家坟(WJ)、罗甸大亭(DT)种群聚为一类, 其种实形态较大, 位于西南部的兴义坝汪(BW)种群单独一类, 其种实形态较小, 其他种群聚为一类, 种实形态介于前两类之间。总体上, 种实性状值有自西向东递增的趋势。Mantel检验表明, 参试种群存在明显的空间结构, 主要体现为渐变群模式。

Association of cone and seed traits of Pinus yunnanensis var. tenuifolia with geo-meteorological factors

Aims Pinus yunnanensis var. tenuifolia is an ecologically and economically important timber tree located at the junction of Yunnan, Guizhou and Guangxi, China. The natural distribution area represents a typical habitat of hot-dry valley. This paper aimed to describe the association between variation patterns of cone and seed traits (CST) and the geo-meteorological factors, explore its ecological adaptability, and provide a reference for the genetic resources conservation, evaluation and utilization.Methods We sampled eight wild populations of P. yunnanensis var. tenuifolia distributed along the Nanpan-Hongshui River basin. The CST among and within populations were analyzed via discriptive statistics and nested ANOVA. Correlations between CST and geo-meteorological were evaluated based on Pearson and canonical correlation coefficients. Principal component analysis and Mantel test were applied to reveal the geographic variation pattern.Important findings Abundant variations of eleven CST among and within populations were indicated by the extremely significant difference of nested ANOVA results (p < 0.001). The variation within population was the main source (the average coefficient of phenotypic differentiation V_ST = 18.65%), and generally, the V_ST of cone traits (24.22%-39.88%) were larger than those of seed and wing traits (4.14%-13.80%), indicating more environment selection pressure on the cone traits. Majority of CST was positively correlated (though part of variable-pairs statistically insignificant) with latitude and longitude, annual average temperature, and negatively correlated with relative humidity and annual rainfall. This result suggests that the CST of P. yunnanensis var. tenuifolia is subjected to strong environmental selection, especially to temperature and relative humidity, prompting the species to adapt the hot-dry environment. Eight natural populations of P. yunnanensis var. tenuifolia were divided into three groups via principal component and cluster analysis. The two Luodian populations (WJ and DT) in the east were grouped into one group, and their cones and seeds were large. A population (BW) of Xingyi in the southwest belonged to a separate group, and its cones and seeds were small. The other populations were grouped together, and their CST fell between the first two groups. On the whole, the CST in P. yunnanensis var. tenuifolia increased from west to east. Mantel test exhibited a significant spatial structure among populations, and the variation pattern of populations was consistent with that of the cline.