Water relations and whole-crown transpiration rate of aged Cryptomeria japonica

老柳杉的水分关系及全冠蒸腾速率

• 批准号: 06660174
• 负责人: TANGE Takeshi
• 金额: $ 1.28万
• 依托单位: The University of Tokyo
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for General Scientific Research (C)
• 财政年份: 1994
• 资助国家: 日本
• 起止时间: 1994 至 1995
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-06660174/
• 关键词: Aged Cryptomeria japonica; Whole-crown transpiration; Vapor diffusion conductance; Water stress; Xylem pressure potential; Stomatal closure; Vapor pressure deficit; Hydraulic conductivity; 本部圧ポテンシャル

In order to clarify the changes in water relations along aging and increasing of tree height, whole-crown transpiration rates, xylem pressure potential and sap flow velocity were measured on a 100-year-old and a 10-year-old Cryptomeria japonica. The results obtained were as follows.(1) The whole-crown transpiration rates were measured with the chamber method. As liner relation was obtained between daily whole-crown transpiration and daily accumulated sap flow velocity, the chamber method was regarded as an available method for the whole-crown transpiration rate.(2) The leaf-mass-based vapor diffusion conductance of crown of the 100-year-old tree were much smaller than those of 10-year-old tree under high air humidity condition. Although the vapor diffusion conductance of the 10-year-old tree sharply decreased along decreasing of air humidity, those of the 100-year-old tree slowly decreased.(3) From the relationship between xylem pressure potentials and sap flow velocities, hydraulic conductivity of each sample tree were determined. The hydraulic conductivity of the 10-year-old tree was smaller than one of the 100-year-old tree under wet soil conditions. The hydraulic conductivity of 10-year-old tree much more increased than the 100-year-old tree along soil dehydration. These results implied that the hydraulic resistance from roots to leaves were larger in the 100-year-old tree than in the 10-year-old tree.(4) In conclusion, it was implied that the lower hydraulic conductivity in the 100-year-old tree than in the 10-year-old tree resulted in the lower crown conductance in the 100-year-old tree, and that the lower crown vapor conductance by stomatal closure resulted in decrease of photosynthetic production in the aged trees.

为探明柳杉水分关系沿着衰老和树高增加的变化规律，对100年生和10年生柳杉的全冠蒸腾速率、木质部压力势和液流速率进行了测定。获得的结果如下。(1)采用气室法测定全冠蒸腾速率。由于全冠蒸腾速率与日累积液流速率之间存在线性关系，因此箱法是一种有效的全冠蒸腾速率测定方法。(2)在高湿度条件下，百年生树冠的基于叶质量的水汽扩散导度远小于10年生树冠。虽然10年生树的水汽扩散导度随着空气湿度的降低沿着急剧下降，但100年生树的水汽扩散导度下降缓慢。(3)根据木质部压力势与液流速度的关系，测定了各样木的导水率。在湿润土壤条件下，10年生树的导水率小于100年生树。沿着土壤脱水，10年生树的导水率比100年生树的导水率增加得更多。这些结果表明，从根系到叶片的水力阻力在100年生的树大于10年生的树。(4)由此可见，100年生树冠层导度低于10年生树，导致了100年生树冠层导度的降低，而气孔关闭导致的冠层导度降低导致了老龄树光合生产的减少。

项目成果

Norisada,M.,Egami,H.,Tange,T.and Sasaki,S.: "Tree aging effects on water relations and whole-crown gas exchange of Japanese red ceder (Cryptomeria japonica D.Don)" Tree physiology. (投稿中).

Norisada, M.、Egami, H.、Tange, T. 和 Sasaki, S.：“树木老化对日本红柏 (Cryptomeria japonica D.Don) 水关系和全冠气体交换的影响” 树木生理学。期间）。

Norisada, M., Egami, H., Tange, T.and Sasaki, S.: "Tree aging effects on water relations and whole-crown gas exchange of Japanese red ceder (Cryptomeria japonica D.Don)" Tree Physiology. (submitted).

Norisada, M.、Egami, H.、Tange, T. 和 Sasaki, S.：“树木老化对日本红柏 (Cryptomeria japonica D.Don) 水关系和全冠气体交换的影响”树木生理学。