Variable chlorophyll fluorescence in response to water plus heat stress treatments in three coniferous tree seedlings

Effects of water and heat stress treatments on chlorophyll fluorescence of Chinese fir (Cunninghamia lanceolata), Masson pine (Pinus massoniana) and western redcedar (Thuja plicata D. Don)_seedlings were monitored during a three-cycle stress period. It was shown that ratio of variable to maximal chlorophyll fluorescence (Fv/Fm) of these three species responded differently to water stress treatments. The Fv/Fm ratio of western redcedar decreased dramatically after water stress, while that of Chinese fir had only a slight reduction and that of Masson pine had no significant change. The experiment also showed that the Fv/Fm ratio of all three species differed significantly under heat stress treatments. Concerning three different water plus heat stress cycles, it was found that the Fv/Fm ratios of Chinese fir and Masson pine measured at the end of each water plus heat stress cycle were not significantly different. However, the Fv/Fm ratio of western redcedar was diminished significantly in response to an increase of stress time. Keywords Chinese fir - Chlorophyll fluorescence - Heat stress - Masson pine - Water stress - Western redcedar CLC number Q945.17 - S791.248 Document code A Biography: Yu Fang-yuan (1965-), male, Ph. Doctor. Associate professor in College of Forest Resources and Environment, Nanjing, Forestry University, Nanjing 210037, P. R. China.Responsible editor: Zhu Hong

竹产品生命周期中碳足迹研究

竹子生长过程中吸收的二氧化碳会转移存储在竹产品中,并在产品碳足迹中以负的二氧化碳排放当量形式被扣除。目前竹产品全生命周期碳足迹研究甚少,且多集中在竹林培育经营阶段的碳固定,忽略了竹产品的碳转移和碳存储。文中简要介绍了基于生命周期评估(LCA)的碳汇计量标准,通过分析主要工程竹产品碳足迹研究结果发现:1)在LCA碳足迹评价标准中,以ISO14067和PAS2050应用最广;两者在目的和范围、抵消、数据和数据质量控制等方面相对一致,在分配和产品比较上存在不同。2)竹产品碳足迹的主要影响因素包括能源结构和加工能耗、运输方式、使用添加材料、加工工艺及产品寿命。3)因加工工艺、能源结构、分析标准和方法、功能单位、系统边界不同,不同类型竹产品碳足迹的评估结果之间难以直接比较,可以通过减少重组竹竹单板生产阶段和胶合层积竹竹条制备阶段的电力和能源消耗减少其碳足迹。4)手工竹工艺品因运输和包装中使用化石能源造成碳足迹偏高。研究结果将为双碳背景下增加产品碳封存、调控全生命周期各环节减排提供技术支撑。