摘要
在新疆昭苏树轮碳同位素组成研究的基础上 ,初步分析了近 2 80a以来云杉内外CO2 浓度比(Ci/Ca)、云杉内部CO2 浓度 (Ci)和水分利用效率 (A/g)的变化 .结果表明 ,在整个分析时段内Ci/Ca相对恒定在 0 5 2左右 ,暗示树木生长对大气CO2 浓度升高的基本响应策略 ;Ci和A/g都有较明显的升高趋势 ,说明可能有更多的碳被固定在树木之中 ;进一步分析表明 ,它们的这种趋势与大气CO2 浓度变化有关 。
The well documented increase in CO 2 content of atmosphere since the beginning of industrialization has been variously attributed to the anthropogenic activities, such as agricultural explosion, global deforestation and enhanced fossil fuel combustion and so on. It was estimated that about one third of anthropogenic CO 2 released to atmosphere was taken up by terrestrial plants. To evaluate how the land carbon reservoir has been acting as a sink to the anthropogenic CO 2 input to atmosphere, it is important to study how plants in forests physiologically adjust to the changing atmospheric conditions. This has been studied intensively using controlled experiments, but it has been difficult to scale short term observations to long term ecosystem level response. However, models of carbon discrimination during carbon fixation show that C 3 plants are not passive recorders: carbon isotopic variations are subjected to strong physiological control through leaf gas exchange regulation. Therefore, records of carbon discrimination in tree ring cellulose could be used to study past variations of the ecophysiology of trees in reaction to environmental variations, in addition to the reconstruction of past environments. In this paper, based on the tree ring series from Zhaosu County of Xinjiang, the changes of the ratio of CO 2 concentration in the intercellular space of leaves to that on the atmosphere (C i /C a ), CO 2 concentration in the intercellular space of leaves (C i ) and plant water use efficiency ( A/g ) derived from carbon isotope chronology were analyzed for the past 240 a. The results show a relatively constant C i /C a value of 0 52 during the whole period, suggesting a strategy of response of plants to increased atmospheric CO 2 concentration. Significant increasing trends of C i and A/g are also found, implying more carbon being fixed; Further analysis shows that their changes are related to atmospheric CO
出处
《冰川冻土》
CSCD
北大核心
2001年第1期41-45,共5页
Journal of Glaciology and Geocryology
基金
中国科学院"九五"重大项目!(KZ95 1 A1 2 0 5
KZ95 1 A1 40 2 0 3
KZ95 2 S1 2 16 )
中国科学院新疆生态与地理研究所阜康荒漠生态
关键词
树轮
碳同位素
植物内外CO2浓度比
水分利用效率
纤维素
大气
tree ring
carbon isotope
ratio of CO 2 concentration in the intercellular space of leaves to that on the atmosphere
water use efficiency
