2003 Fiscal Year Final Research Report Summary
Responses of leaves and shoots to environmental variables and tree growth
| Project/Area Number |
13440231
|
|---|
| Research Category |
Grant-in-Aid for Scientific Research (B)
|
| Allocation Type | Single-year Grants |
|---|
| Section | 一般 |
|---|
| Research Field |
生態
|
|---|
| Research Institution | Osaka University |
|---|
Principal Investigator |
TERASHIMA Ichiro Osaka University, Graduate School of Science, Professor, 大学院・理学研究科, 教授 (40211388)
|
|---|
| Project Period (FY) |
2001 – 2003
|
| Keywords | tree / photosynthesis / water relations / tree architecture / translocation / sink vs source / cell wall / biomechanics |
|---|
| Research Abstract |
1.By concurrent measurements of gas exchange and carbon isotope, we established that thick mesophyll cell walls in tree leaves, in particular those of evergreen trees, is a considerable barrier to photosynthetic CO_2 diffusion.
2.We clarified why sun leaves should be thicker than shade leaves. Thickness if important for increasing the surface area for CO_2 dissolution. We also found that palisade tissue cells divide periclinally in response to signal from the mature leaves. When mature leaves are exposed to high light, palisade tissue cells in developing leaves divide periclinally irrespective of the light conditions of the developing leaves.
3.We described development of photosynthetic activity in the leaves of evergreen tree species. The maximum photosynthetic rate was observed well after the full leaf expansion.
4.We analyzed behavior of the bulk elastic modules, an important parameter for determining water relations, in mature tree leaves. Bulk elastic modules decreased in response to water stress so that cell turgor was maintained. These changes were reversible and quicker than changes in osmotic potential.
5.We applied the pipe model theory in the derivative form to describe tree growth. Light interception and long and short shoot differentiation are important determinants of thickness growth of the trees.
|
