植物生态学报 ›› 2006, Vol. 30 ›› Issue (2): 295-301.DOI: 10.17521/cjpe.2006.0039

所属专题: 碳水能量通量

• 研究论文 • 上一篇    下一篇

西双版纳热带季节雨林晴天CO2交换的日变化和季节变化特征

赵双菊1,3(), 张一平1,*(), 于贵瑞2, 宋清海1,3, 孙晓敏2   

  1. 1中国科学院西双版纳热带植物园,昆明 650223
    2中国科学院地理科学与资源环境研究所,北京 100101
    3中国科学院研究生院,北京 100039
  • 接受日期:2005-06-02 发布日期:2006-03-30
  • 通讯作者: 张一平
  • 作者简介:*E-mail: yipingzh@xtbg.ac.cn
    E-mail: zsj@xtbg.ac.cn
  • 基金资助:
    中国科学院知识创新重大项目(KZCX1-SW-01-01 A4);国家973项目(2002CB412501)

DIURNAL AND SEASONAL CO<sub>2</sub> EXCHANGE ON CLEAR DAYS IN A TROPICAL SEASONAL RAINFOREST OF XISHUANGBANNA

ZHAO Shuang_Ju1,3(), ZHANG Yi_Ping1,*(), YU Gui_Rui2, SONG Qing_Hai1,3, SUN Xiao_Min2   

  1. 1Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Kunming 650223, China
    2Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China
    3Graduate school of Chinese Academy of Sciences, Beijing 100039, China
  • Accepted:2005-06-02 Published:2006-03-30
  • Contact: ZHANG Yi_Ping

摘要:

应用2003年11月~2004年10月晴好天气涡度相关通量观测资料,对西双版纳热带季节雨林CO2交换的日变化和季节变化进行分析。结果表明:雾凉季、干热季和雨季的净生态系统CO2交换(NEE)均呈现出单峰型曲线的日变化趋势,昼间其变化规律较强,夜间呈波动状态。昼间NEE(取绝对值)雾凉季和雨季均显著大于干热季;夜间NEE雨季显著大于干热季,而干热季显著大于雾凉季。光合有效辐射是影响NEE日变化的主要因素,但不是造成季节差异的主要因素;饱和水汽压差和气温对NEE的季节差异有较大贡献。另外,应用Michaelis_Menten模型对昼间不同饱和水汽压差和气温下NEE对光合有效辐射的响应进行分析,结果表明:各季节较高饱和水汽压差下的表观最大光合速率(Pmax)、表观暗呼吸速率(Re)比较低饱和水汽压差下的PmaxRe大,而表观光量子产额(α)则相反。各季节较高气温下的Re比较低气温下的Re大;雾凉季气温的差异对Pmaxα的影响较小;干热季和雨季较高气温下的α较小。

关键词: 净生态系统CO2交换, 涡度相关, 日变化和季节变化, 热带季节雨林, 西双版纳

Abstract:

Tropical forests play an important role in altering the carbon budgets of terrestrial ecosystems. We examined patterns of diurnal and seasonal net ecosystem CO2 exchange (NEE) in a tropical seasonal rainforest of Xishuangbanna on clear days between November 2003 and October 2004. We found that the diurnal dynamics of NEE showed a single_peaked curve. During daytime throughout the year, NEE increased with solar radiation after sunrise, but fluctuated after sunset. Values of NEE (absolute values) in the foggy_cool and wet seasons were greater than those in the dry_hot season during daytime. During the night, NEE values were dominated by soil temperature and soil water content and were highest in the wet season, followed by those in the dry_hot season and lowest in the foggy_cool season. NEE, water vapor deficit (VPD) and air temperature (Ta) curves all showed pronounced seasonal variation, but photosynthetically available radiation (PAR) did not vary significantly. Maximum photosynthesis rates (Pmax) and dark respiration rates (Re) were greater when VPD≥16 hPa than whenVPD<16 hPa, whereas photon density (α) was the opposite. Re was also greater when Ta≥25 ℃ than whenTa<25 ℃ in the three seasons.α was reduced when Ta≥25 ℃ in the dry_hot and wet seasons. ThePmax increased in the dry_hot season and decreased in the wet season when Ta≥25 ℃. Our data suggested thatPAR is the main factor influencing NEE diurnal dynamics, whereas both VPD and Ta play a major role in regulating NEE seasonal dynamics.

Key words: Xishuangbanna tropical seasonal rainforest, Net ecosystem CO2 exchange, Eddy covariance, Diurnal and seasonal variation