2006 Fiscal Year Final Research Report Summary
Studies on water stress avoidance of trees in relation to the adjustment of hydraulic conductivity of xylem
| Project/Area Number |
16380110
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
林学・森林工学
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| Research Institution | Kyoto Prefectural University |
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Principal Investigator |
IKEDA Takefumi Kyoto Prefectural University, Graduate School of Agriculture, Professor, 農学研究科, 教授 (50183158)
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| Co-Investigator(Kenkyū-buntansha) |
MARUTA Emiko Toho Unlversity, Fac. Sclence, Assoclate Professor, 理学部, 助教授 (90229609)
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| Project Period (FY) |
2004 – 2006
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| Keywords | Pinus thunbergii / embolism / cavitation / Abies mariesii / water relations parameter / water stress |
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| Research Abstract |
1. Water stress avoidance in pine seedlings growing under water deficit condition in relation to vulnerability of xylem cavitation
Seedlings of Pinus thunbergii control water balance as following manners; osmotic adjustment to keep turgor pressure above zero, closing stomata at higher leaf xylem pressure potential. Dcreasing in hydraulic conductivity of xylem due to xylem cavitation does not function successfully in controlling water balance of whole tree.
2. The effects of xylem cavitation to deformed tree shape of Abies mariesii in ecotone between subalpine zone and alpine zone
Above snow-shoot xylem of A.mariesii was easy to lose hydraulic function because of more vulnerable to xylem cavitation, inducing leaf and shoot death. Needles of A.mariesii at the ecotone and Pinus pumila at the alpine zone change from green to brown in early spring, resulting in the death of leaf cells. One of perspective reasons is thought that the damage of cuticle layer of needle surface due to a strong wind, including an ice and snow particles, promote the dehydration of leaf and then the trees wilt. Anatomical study to confirm such an idea showed that there were wound in P.pumila, but no wound in A.merisii.
3. Vulnerability to xylem cavitation in some conifers
Comparative study showed that genus Pinus growing under bad site condition was more vulnerable in comparison with Cryptomeria japonica and Chamaecyparis obtusa growing under better site condition and to prevent decreasing in hydraulic conductivity from xylem cavitation the genus Pinus adjusted transpiration at higher leaf xylem pressure potential.
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