Variation in photosynthetic photon flux density within a tropical seasonal rain forest of Xishuangbanna, south-western China
  • 【DOI】

    10.3321/j.issn:1001-0742.2005.06.018

  • 【摘要】

    The effects of canopy development, solar angle, and weather conditions on temporal variation in photosynthetic photon flux density(PPFD) at three heights within a tropical rain forest canopy in Xishua... 展开>>The effects of canopy development, solar angle, and weather conditions on temporal variation in photosynthetic photon flux density(PPFD) at three heights within a tropical rain forest canopy in Xishuangbanna, China, were examined. PPFD was measured every second and stored as 10-min averages from 1 December 2002 to 30 November 2003. PPFD variability was examined at three different tempcral scales. Specific days in March, September, and December with clear and overcast sky conditions were selected to separate the effects of leaf area index(LAI) and solar angle on diumal variability. On both clear and overcast days, mean daily average PPFD was significantly different between March and September at all heights, except 10 m on clear days, suggesting that LAI directly influences PPFD. In contrast, the differences in daily average PPFD among three heights between September and December were likely due to variation in solar angle. In addition, daily average PPFD at all locations were significantly lower under overcast than clear sky conditions in March, September and December. Over the year-long study, the mean daily total PPFD at 21 m, 10 m and 4 m was 2.8, 2.7 and 0.7mean daily total PPFD occurred at the same heights among different seasons, and diurnal, day-to-day and seasonal PPFD varied at different heights within the canopy. The possible effects of light variability on physiological and morphological responses of plants are discussed. 收起<<

  • 【作者】

  • 【作者单位】

    Xishuangbanna Tropical Botanical Garden/Xishuangbanna Tropical Botanical Garden/Research Center for Eco-Environmental Sciences

  • 【刊期】

    环境科学学报(英文版) ISTIC SCI 2005年6期

  • 【关键词】

    photosynthetic photon flux density  temporal light variability  tropical seasonal rain forest canopy  Xishuangbanna 

  • 【基金项目】

    中国科学院知识创新工程项目 the Grant Program of the Chinese Academy of Sciences 云南省自然科学基金