温带-亚热带栓皮栎种子形态的变异及其与环境因子的关系

在区域尺度上(25.14°-40.25° N, 99.87°-122.07° E), 采集20个栓皮栎(Quercus variabilis)种群的种子样品, 测定种宽、种长, 并计算宽长比形态指标, 探讨了区域尺度上种子形态变异特点及其与环境因子的关系。结果表明, 栓皮栎种子的宽度和长度变化幅度分别为1.21-2.18 cm和1.20-2.96 cm; 宽长比的变化幅度为0.57-1.10。栓皮栎的种宽与种长呈显著的正相关关系。单因素方差分析表明, 种宽、种长和宽长比在种群间差异显著(p < 0.001)。种长与等效纬度呈负线性(R² = 0.18; p = 0.05), 与经度呈凸型的变异关系(R² = 0.43; p = 0.009)。种宽和种长与最热月平均气温呈极显著正相关(R² = 0.35; p = 0.006; R² = 0.30; p = 0.012), 而与最湿季降水量呈显著负相关(R² = 0.28, p = 0.019; R² = 0.24, p = 0.017)。种子宽长比没有明显的变化趋势, 大致趋于恒定(0.88 ± 0.08)。

Variations of seed morphology related to climate for Quercus variabilis across temperate-subtropical China

Aims Our objective was to reveal the pattern of variations in seed morphology in Quercus variabilis across temperate-subtropical China and to determine how they respond to climate change.
Methods Seed samples were collected from 20 natural Q. variabilis populations across eastern China in autumn 2011. Seed width (SW) and seed length (SL) were used as measures for seed size, and the ratio of width and length (SW/SL) for seed shape.
Important findings The SW and SL ranged from 1.21 to 2.18 cm and from 1.20 to 2.96 cm, respectively, and the SW/SL ratio ranged from 0.57 to 1.10. There were significant differences among the populations (p < 0.001). There was also a significant linear relationship between SW and SL. Seed length increased significantly with mean temperature of warmest month (MTW), decreased with precipitation of wettest quarter (PWQ), and displayed negative linear and humped-shape relationships with equivalent latitude (ELAT) and longitude (LON), respectively. Seed width had a significant positive correlation with MTW and negative correlation with PWQ. The SW/SL was almost constant along the latitude and climate gradients. These results have important implications for understanding how the morphology of seeds responds to climate change.