广东连州上柏场报春苣苔种群及其生境特征

Habital characteristics of Primulina tabacum populations in a cave at Shangbaichang, Lianzhou, Guangdong

2012年用自动记录仪对已知最大规模的广东连州上柏场报春苣苔Primulina tabacum种群所处生境的气温、相对湿度进行为期1年的监测，每季度监测植物叶片绿色度和种群数量；测定土壤、岩石、水体和植物体多种元素的含量，计算植物的吸收系数，以期为种群的保护和发展提供基础资料。结果表明：岩洞的气温变幅为1．262～24．847℃，平均气温和温差均为洞内〉洞中〉洞口；相对湿度为洞15〉洞中〉洞内，洞内湿度的变幅最大。报春苣苔能较好地适应4000lx以下的光强，低于洞外最强光的10％。所测定的元素含量，以ca最高，且岩石〉土壤〉植物体，以N最低，且植物体=土壤〉岩石。地面植株对元素的吸收系数顺序为H〉N〉C〉P〉K〉Na〉Ca〉Mg〉A1，侧壁植株的为H〉C〉K〉Mg〉N〉Ca〉Na〉P〉A1。植株叶片绿色度为洞口〉洞中〉洞内，但差异不显著。种群数量波动较大，夏季和秋季多，冬季和早春少，与气温和相对湿度有较明显相关性。结果提示，报春苣苔虽要求石灰岩生境．但对不同牛态因子仍具一定适廊性．为迁地傈护提供了王单论依据．

Using the sensor of an automatic onset HOBO mini-weather station, the air temperature, air relative humidity were monitored for one year （2012） in a lime cave located at Shanbaochang, Lianzhou, Guangdong where the national Grade I key protected plant species Primulina tabacum grows. The leaf SPAD values and the population sizes were measured seasonally. The elemental contents of soil, rock, underground water and plant were also measured, and the assimilative coefficient by plant were calculated, in order to provide basic data for protecting and enhancing the plant population. Results showed that the air temperature ranged from 1.622 ℃ to 24.847℃. Mean air temperature and the range of temperature were in the following order inner〉 middle〉 entrance of the cave. The order of range in air relative humidity was entrance〉 middle〉 inner of the cave. The inner location had the greatest range in humidity. P tabacum was shown to be adapted to low light density within 4 000 lx, which was less than 10% of the highest light density found outside the cave. The Ca content which was the highest concentration of the elements measured were in the following order rock〉soil〉plant. Meanwhile, the N content in plant ~ soil〉 rock was lowest of the element measureed. The assimilative coefficient was in the following order H〉N〉C〉P〉K〉Na〉Ca〉Mg〉A1 for individual plants growing on the cave floor, and H〉C〉K〉Mg〉N〉Ca〉Na〉P〉A1 for individual plants growing on the jamb rock wall. Leaf SPAD values were in the following order among the locations entrance〉 middle〉 inner of the cave, with no significant difference among locations. The population size fluctuated, largest in summer and in autunm. Lowest populations were found in winter and early spring, which were related to the air temperature and relative humidity. Although P tabacum growth is restrict in lime cave habitats, the results in this paper suggest that the species is adapted for some changes in different ecological factors, and maybe is useful for the ex-situ conservation of the plant.