【摘要】 在青藏高原东部的一个高山雪床,沿着融雪梯度设置了早融、中间、晚融3个融雪部位,对每个部位的环境因子、大卫马先蒿的个体生长特征及其繁殖特征进行了测量,并在3个部位间对这些特征进行了比较。无雪期长度、土壤水分含量和表土温度的每日变化幅度在部位间有显著的差异,但土壤营养成分和pH并无明显的变化。从早融部位到晚融部位,大卫马先蒿的株高、单株叶数、单叶面积以及比叶面积显著增加,地上生物产量和总生物量也增加,而地下生物量以及地下生物量与地上生物产量之比却降低。花序中段和下段的花数、单花种子数和种子千粒重随融雪的推迟而增加,花序上段的花数、单花种子数和种子千粒重在融雪梯度上没有明显的变化;就整个花序而言,这些繁殖特征随融雪的推迟而增加。大卫马先蒿的个体生长及繁殖特征主要受冻融交替的影响。更多还原

【Abstract】 In an alpine snowbed on the eastern Tibetan Plateau,three portions were established along the snowmelt gradient.Environmental factors,individual growth and reproduction of Pedicularis davidii var.pentodon were measured and compared among the portions.It was found that snow-free period,soil water content and daily range of diurnal soil surface temperature were significantly different among the three portions,whereas soil nutrients and pH did not change significantly.Height,leaves per stem,area per leaf and specific leaf area increased significantly from early-to late-melting portion.From early-to late-melting portion,aboveground and total biomass increased,while belowground biomass and the ratio of below-to aboveground biomass decreased.Number of flowers,seeds per flower and 1000-seed weight increased in the lower and middle section of an inflorescence,whereas they almost kept constant in the upper section of an inflorescence.As for the whole inflorescence,these reproductive parameters increased from early-to late-melting portion.Individual growth and reproduction of Pedicularis davidii var.pentodon were mainly affected by freeze-thaw alternation.更多还原