对兰州市银滩黄河湿地10种植被优势种千屈菜、芦苇、酸模叶蓼、稗草、龙葵、反枝苋、曼陀罗、红豆草、藨草、水莎草的光合作用影响因子进行了分析，探讨了多种生理、生态因子对湿地植被优势种净光合速率(P n )的影响程度。采用主成分分析法对兰州银滩黄河湿地10种植物优势种的光合作用影响因子进行了分析，反枝苋提取了前3个主成分，其他9种植物提取了前2个主成分。结果表明，影响植物光合作用因子的主要成分中，第1主成分里光强和温度对湿地植物净光合速率的贡献很大，第2主成分里蒸腾速率(T r )、胞间 CO2浓度(C i )、气孔导度(G s )对净光合速率的影响较大，每天10：00~15：00各植物影响光合作用的因子主成分得分排序较高，说明强烈的太阳辐射是引起一天中空气温度、相对湿度等一系列环境条件变化的根本原因，进而通过影响气孔导度和蒸腾速率等生理因子影响植物的净光合速率。%The factors of photosynthesis of vegetation in Yintan Wetland of Yellow River in Lanzhou City is analyzed, the research is explored the physiological, ecological factors’ influences on the net photosynthetic rate (P n ) of the dominant species in Wetland. The dominant species are Lythrum salicaria ,Phragmites communis ,Polygonum lapathifolium ,Echinochloa crusgalli ,Solanum nigrum L ., Amaranthus retroflexus , Datura stramonium , Onobrychis viciaefolia , Scirpus triqueter , J uncellus serotinus .By using principal component analysis(PCA)method,photosynthesis of ten kinds of dominant species of vegetation in Yintan Wetland of Yellow River in Lanzhou is analyzed.By extracting the first three principal components of Amaranthus retroflexus and the first two principal components of the other nine kinds of plants,the main ingredients of factors which affect photosynthesis can be identified effectively by using PCA. In the first principal component, the intensity and temperature of light contribute to the photosynthetic rate of Wetland plants to a large degree.In the second main component, transpiration rate(T r ),intercellular CO2 concentration(C i ),stomatal conductance(G s )have a big impact on photosynthetic rate. According to higher-ranking scores of vegetation photosynthesis which are influenced by principal components between 10 am to 3 pm every day. It indicates that strong solar radiation is the fundamental cause of the change,such as air temperature,relative humidity and a series of environmental conditions in the day.Moreover,it affects net photosynthetic rate of plants through the influence on stomatal conductance,transpiration rate and other physiological factors.
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