ECCENTRIC GROWTH AND GROWTH STRESS IN INCLINED STEMS OF GNETUM GNEMON
| Autor: | Abubakar M. Lahjie, Mitsuaki Sawada, Chisato Ko, Masato Yoshida, Sachie Yagami, Hiroyuki Yamamoto, Kazuhiko Fukushima, Yasuyuki Matsushita, Abraham Kule, Tatsuya Shirai, Mikuri Inatsugu |
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| Rok vydání: | 2015 |
| Předmět: | |
| Zdroj: | IAWA Journal. 36:365-377 |
| ISSN: | 2294-1932 0928-1541 |
| Popis: | Gnetum gnemon L. (Gnetales) forms hardwood-like secondary xylem in its trunks and branches although it is a gymnosperm. The present study tested the surface growth stress in relation to anatomical and chemical properties of the secondary xylem in inclined and vertical stems of G. gnemon using morphological and chemical composition analyses. Secondary growth was promoted on the upper half of the cross section in an inclined stem; at the same time, tensile growth stress increased on the upper side and decreased on the lower side of the inclined stem. However, formation of reaction wood fibers was not detected on either side. The microfibril angle was associated with differences in tensile growth stress. Thus, we conclude that negative gravitropism in G. gnemon is caused by a synergistic effect of increased tensile growth stress as well as the promotion of secondary growth on the upper side of the inclined stem. Our results are comparable to the negative gravitropism observed in the family Magnoliaceae, which does not form gelatinous fibers in its tension wood. |
| Databáze: | OpenAIRE |
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