大气CO2浓度升高对植物的直接影响-国外十余年来模拟实验研究主要手段及基本结论

 本文针对国外近十几年来在CO2浓度升高对植物的直接影响方面所开展的生理生态学研究方法、动态、基本结论、存在问题等内容做了简要的介绍。大气CO2浓度在过去200年内已增加了80μmol·mol-1，生长在高CO2环境下的植物，其生理生态、形态及化学成分等方面将会发生相应的变化。表现在光合作用速率出现不同程度的提高；呼吸作用受抑制；气孔密度减少，水分利用效率增加；生物量及产量增加；一些关键蛋白质及酶、非结构性碳水化合物含量增加；组织中的氮、硫等元素含量降低；根系及花的发育也随CO2浓度的升高而提前等。不同光合途径(C3、C4及CAM)及不同植被类型(自然植被、栽培植被)的植物随CO2浓度发生的上述指标的变化在长期反应与短期反应方面具有很大的差异。另外，实验控制条件如温度、光照、水分、养分甚至实验装置(如花盆)的大小对预测结果也有很大的影响。

Response of Plant Growth to Elevated CO2: A Review on the Chief Methods and Basic Conclusions Based on Experiments in the External Countries in Past Decade

Plants growing in high CO2] levels may change with their physiological, morphological and plant chemical features. Photosynthetic rate may be enhanced while respiration may be inhibited. Stomatal density may become fewer while water-use efficiency (WUE)increases with CO2] increases. Biomasses and yields of plants growing in high CO2] may also increase, together with the total non-carbohydrate (TNC) and some key proteins and enzymes increasing. But the C: N ratio could become lower. Contents of some elementary element such as N, S and P may decrease. The development of roots and flowers can be also affected by the elevated CO2] levels. These conclusions, however, are with some kinds of uncertainty. Plants with different photosynthesis paths (C3 ,C4 and CAM) and different vegetation types (natural and artificial vegetation) have the different response to the electedCO2]. Long-term and short-term responses of the same plants may differ on the other hand, controlled environmental factors during experiments such as light, temperature, water availability, nutrient content, air pollution, even pot sizes applied for experiment, may have a profound effect on the results. This paper reviews some main methods, leading conclusions and existing problems in the experiments of plant growth responses to high CO2], based on the existed experimental results in some external countries in the past decade.