暗紫贝母的物候和鳞茎在海拔梯度上的变化

Variation of phenology and bulbs of Fritillaria unibracteata along altitudinal gradients

在青藏高原东部的一个高山山坡上沿着海拔高度设置低、中、高3个海拔部位,在高、低2个海拔部位之间进行暗紫贝母植株的移植实验,并观察每个部位的生态因子、暗紫贝母的物候和鳞茎大小。结果表明,积雪融化完的时间、气温、土壤含水量在各部位之间有明显的差异;暗紫贝母各物候期都是在低海拔部位最先出现,中海拔部位次之,在高海拔部位最迟出现,各物候期高海拔部位比低海拔部位晚约14～25d;鳞茎平均单粒重量随着海拔的升高而降低,和低海拔部位相比,高海拔部位的鳞茎单粒重量减少了23.1%。移植实验的结果进一步证实了物候和鳞茎在高、低海拔部位之间的变化规律。暗紫贝母物候和鳞茎在海拔梯度上的变化主要是由无雪期的长度、气温以及土壤含水量等因子决定的。

To provide theoretical support for artificial cultivation of Fritillaria unibracteata, and to lay a foundation for protection of its wild resource, the effects of altitudinal height on phenology and bulbs of the species were studied. In this study, three locations （low, medium and high） were established along altitudinal gradients on a mountain slope of the eastern Tibetan Plateau, and a transplant experiment was carried out. In this experiment, 30 turfs in which individuals of F. unibracteata grew were transplanted between the high and the low location. Ecological factors at each location, such as snowmelt timing, soil water content, air temperature and soil pH were tested. In addition, phenological phases including plant emergence, first flowering, peak flowering and consenescence were observed at three day intervals, and bulbs at each location were weighed in September,2009. The results showed that phenological phases and most ecological factors given above were significantly different between locations. Snowmelt timing at the low location was nearly a month earlier than that at the high location and soil water content at the low location was 30.3% lower than that at the high one. Air temperature was 2.7℃ （March）, 3.0℃ （April） and 5.3℃ （May） higher at the low location than that at the high location. However, pH at all locations did not differ. All phenological phases appeared first at the low location, second at the medium location and finally at the high location. Compared with the low location, phenological phases at the high location were 14--25 d later. Single bulb weight at the low location was the heaviest, reaching 282.4 mg. With an increase of elevation, weight of si single bulb weight was only 217.4 mg, a decrease of 23.1% compar ngle ed w bulbs decreased. At the high location, ith the low location. That the phenolo gy and bulb weight changed with altitude was further confirmed by the results of a transplant between high and low locations. Individuals transplanted from the low to high location always showed consistent traits with those originally at the high location, and vice versa. Changing trends of phenology and bulbs with altitude was mainly affected by length of snow free period, air temperature and soil water content. In conclusion, altitude exerted a strong influence on phenology and bulbs of F. unibracteata.