两种喀斯特生境植物旱雨季生理指标特征

喀斯特地区旱雨季降水分布的显著差异导致其生境植物的生理生态差异.为评估这种差异,本研究选取喀斯特森林次生林常见落叶植物红背山麻杆(Alchornea trewioides Muell.)和常见经济作物桂花(Osmanthus fragrans Lour.)进行分析.通过对这两种植物旱、雨季饱和净光合速率(Pmax)、比叶面积(SLA)、叶氮量(Nmass-leaves)、茎氮量(Nmass-sterm)、叶绿素a、b总量(Chla+b)及其比值(Chla/b)的比较分析,结果显示:两种植物的上述所有指标在旱季均呈下降趋势,红背山麻杆在不同季节的生理指标均高于桂花,营养获得和储存能力较强.红背山麻杆作为喀斯特特殊生境优势种比桂花在生理指标方面显示出更好的适应性,这可能是其成为喀斯特森林群落的先锋种和优势种的原因.

COMPARISON FOR PLANT PHYSIOLOGY OF TWO SPECIES IN SOUTHWEST CHINA KARST FOREST

The distribution of precipitation in karst region of southwest China is significantly different in dry and rain season which leads diversity in plants physiological characteristic.In order to know the distinctions of plant physiology and analyze the adaptability,two species(Alchornea trewioides Muell.and Osmanthus fragrans Lour.) in Southern China karst region were studied.Certain plant physiological indexes(Pmax,Nmass in root and leaves,SLA,Chla+b and Chla/b) were compared.All of these indexes were tested every month in spring(from March to May,2008) and autumn(from September to November,2008).The results indicated that all of these indexes were all decreased in autumn,and the indexes of Alchornea trewioides were higher than Osmanthus fragrans.It means the capability of nutrient gain and store of Alchornea trewioides are higher than Osmanthus fragrans.As a pioneer and dominant species in karst forest,Alchornea trewioides,shows better adaptability in plant physiological.