基于39个地理分布信息和19个生物气候因子,利用BIOCLIM生态位模型对紫玉兰(Yulania liliiflora(Desr.) D. L. Fu)潜在适生区进行预测。结果显示,紫玉兰自然分布于云南、四川、贵州、湖北、甘肃、重庆、福建等地海拔300～1600 m的中低山区。当前气候条件下,贵州苗岭是其主要适生区;随着全球气候变暖(CO2浓度倍增情况下),紫玉兰的适生区有向高海拔地区收缩的趋势,而在分布区的东北界,其潜在分布范围将扩散至湖南中部和浙江东部地区。影响紫玉兰地理分布格局的重要因素是水热条件的综合效应。ROC曲线检验的AUC值(0.998)表明,采用BIOCLIM模型对紫玉兰潜在分布区的预测结果准确性较高。本研究在气候变暖的大环境下分析紫玉兰的适生性,可为紫玉兰种质资源的保护利用提供依据。
This paper dealt with the effects of Pb 2+,Cd 2+ and their combined pollution on the contents of chlorophyll,potassium and calcium in Thuidium cymbifolium.The results showed that except at 0.1 mg Cd 2+·L -1,the chlorophyll content decreased with increasing Pb 2+ and Cd 2+ concentrations,which was 18% of the control at 100 mg Cd 2+·L -1,and decreased by 48.6% at 200 mg Pb 2+·L -1.The potassium and calcium contents also decreased with increasing pollutants concentrations,being decreased by 61.1% at 100 mg Cd 2+·L -1.Cd 2+ had a stronger toxicity than Pb 2+,and the toxicity of their combined pollution was stronger than that of each pollutant.Pb 2+ could increase the toxicity of Cd 2+.
