关键词: 实验技术, 细胞酶, 生理生态, 个体生长, 大气CO2浓度增加

Abstract: An introduction of methodology and techniques being adopted for experimental investigation of plants and ecosystems to elevated CO₂, including genetically manipulation, controlled environmental facilities, branch bags or chambers, open-top chambers, free-air controlled enrichment system, natural CO₂ vents, and eddy covariance measurement, was briefly made. The ultimate results of internationally current studies on elevated atmospheric CO₂ was reviewed with respect to responses of cells, leaves, individual plants. Most early experiments on CO₂ enrichment of trees were done in the same ways on agricultural crops, using potted juvenile seedlings and fixednutrient capital, leading to constrained root groWth, nutrient limitation, poor coupling to the atmosphere and lackof sustained active sinks for photosynthate. Also, these experiments were generally done in the short term, insteadof gradual adaptation and acclimation Processes. All these contribute to a large variations observed inphysiological and growth response of plants to elevated CO₂. Elevated CO₂ induced decrease in stomatalconductance by a range of 10%-69%, and increase in growth by a range of 20%-120%. Broad-leaved trees aremore sensitive to elevated CO₂ than conifers. Interaction between the responses of plants to elevated CO₂ and theavailability of nutrient raise important questions. Changes in the balance between rates of uptake of CO₂ and ofinorganic nutrient, especially N, may result in changes in the translocation of carbon and nitrogen within plants.Although nutrient has been increasingly involved in studies of the impact of elevated CO₂ on plant growth,andphysiology, the quantitative effects of the rate of supply of nutrients are often neglected in experiment design,leading to difficulties interpreting CO₂ responses and interactions between CO₂ and nutrition.Recent experiments, by adopting the steady-state nutrition approach, demonstrated that there was no effectof elevated CO, on allocation of carbon between roots and shoots with a high rate of N supply, but that a highfraction of plant dry mass was found in roots, primarily in fine roots when the rate of N-supply was low. Thedown regulation of photosynthesis in parallel by decrease in rubisco activities occurred regardless of nitrogensupply.The acclimation process of photosynthesis to elevated CO₂, the mechanism of CO₂ regulating stomatalaction, and the long term-effects of interaction between carbon and nitrogen on growth and physiologicalresponses of plants to elevated CO₂ were strongly recommended for future research.

Key words: experimental techniques, cellular enzyme, physiology, individual plants, elevated CO₂