| Project/Area Number |
06660174
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
林学
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| Research Institution | The University of Tokyo |
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Principal Investigator |
TANGE Takeshi Univ.Tokyo, Fac.Agric., Assoc.Prof., 農学部, 助教授 (20179922)
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| Co-Investigator(Kenkyū-buntansha) |
KOJIMA Katsumi Univ.Tokyo, ANESC,Assoc.Prof., アジア生物資源環境研究センター, 助教授 (80211895)
YAGI Hisayoshi Univ.Tokyo, Fac.Agric., Prof., 農学部(林), 教授 (80191089)
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| Project Period (FY) |
1994 – 1995
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| Project Status |
Completed (Fiscal Year 1995)
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| Budget Amount *help |
¥2,000,000 (Direct Cost: ¥2,000,000)
Fiscal Year 1995: ¥700,000 (Direct Cost: ¥700,000)
Fiscal Year 1994: ¥1,300,000 (Direct Cost: ¥1,300,000)
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| Keywords | 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 |
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| Research Abstract |
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.
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