| Budget Amount *help |
¥2,200,000 (Direct Cost: ¥2,200,000)
Fiscal Year 1989: ¥400,000 (Direct Cost: ¥400,000)
Fiscal Year 1988: ¥1,800,000 (Direct Cost: ¥1,800,000)
|
|---|
| Research Abstract |
Inclined dicotyledonous trees show characteristics of eccentric growth and reaction wood in common with coniferous trees. But in case of angiosperm trees, the reaction wood is formed on upper side of learning stem, and it exhibits anatomically different features from gymnosperms. Additionally, leaning trees do not always exhibit pronounced changes of tension wood, because some species show no marked eccentric and anatomical features as tension wood. In conifers the role of indole-3-acetic acid (IAA) has been postulated and understood as causal factors in controlling the formation of compression wood. But application of the concept to tension wood formed in angiosperms must be difficult, because it is questionable whether IAA concentration becomes higher in nature on upper side of inclined stem than lower side. In this study, appearances of eccentric growth and anatomical features as tension wood were, observed throughout stems in three species of dicotyledonous trees, sioji (Fraxinus s
… More
paethiana), mizunara (Quercus crispula) and oobaasagara (Pterostyrax hispida), inclined artificially. Furthermore, distribution of IAA and abscisic acid (ABA) levels were quantitatively examined on two positions of leaning stems, in relation to formation of tension wood.
(1) Although two species, sioji and mizunara, exhibited eccentric growth after inclination, in oobaasagara it was not recognized. It was substantiated that there are some species which the inclination was not associated with appearance of eccentricity. (2) Anatomical features as tension wood were recognized in leaning stems of sioji and mizunara, but not oobaasagara. On upper side in inclined stems of sioji, reduction of lignification was confirmed by observing sections stained with safranine-fastgreen, though the gelatinous fibers were not found the inside of secondary walls which was anatomically typical features of tension wood. In mizunara the formation of tension wood was confirmed by appearance of crescent-shaped and light colored marks in xylem formed after inclination which was able to observe with the naked eye, as a feature of tension wood. (3) IAA levels examined in mizunara forming typical tension wood after inclination exhibited no apparent differences among upper, lateral and lower sides. It may be considered that IAA has little or a little role in tension-wood formation, whereas it effects strongly on compression-wood formation in conifers. In case of dicotyledonous trees, ABA may be more important substance for formation of tension wood, and the result of the quantitative analysis will be expected. Less
|
