融雪时间对长毛风毛菊个体生长的影响

Effect of snowmelt time on individual growth of Saussurea Hieracioides Hook. F.

在青藏高原东部的一个季节性高山雪场,沿着融雪梯度设置三个梯度部位,在每个部位测量融雪时间及土壤水分等因子,并测定长毛风毛菊(Saussurea hieracioides Hook.F.)的单株叶数、单叶面积和地上生物量等个体生长特征.结果表明,晚融部位的生长季长度比早融部位迟了将近一个月,晚融部位的土壤水分含量比早融部位高,在早融到晚融的梯度上长毛风毛菊的个体生长逐渐增加;长毛风毛菊个体特征的变化与融雪时间的早晚相反而与土壤含水量高低一致.

In a seasonal alpine snow field in the east of Qinghai - Tibet Plateau, three portions were estab- lished along snowmeh gradient. At each portion, snowmelt time, soil moisture and individual growth （including leaves per individual, area per leaf and aboveground biomass） of Saussurea Hieracioides Hook. F. were measured. The results showed that the length of growing season at late - melting portion was nearly one month later than that at early - melting portion. However, soil moisture at late - melting portion was higher than that at early - melting portion. In addition, individual growth gradually increased from early - to late - melting portion. The results suggested that individual growth of this species was reverse to snowmeh timing, whereas it was consistent with soil moisture.