No description available.

No description available.

No description available.

No description available.

主催：JST/CREST，Vrije University, ALTERRA, IBPC

Thesis (Ph. D.)--University of Oregon, 1999. / Typescript. Includes vita and abstract. Includes bibliographical references (leaves 87-98). Also available for download via the World Wide Web; free to University of Oregon users. Address: http://wwwlib.umi.com/cr/uoregon/fullcit?p9947979.

Shoot production and in vitro performance of Juglans nigra L and Quercus rubra L. was studied where 0, 3, 10, 30, or 100mM benzyladenine (BA) in a 20% white exterior latex paint diluted with deionized water were applied separately to 40 cm branch segments to determine the most effective concentration of benzyladenine on bud break and shoot growth. Softwood shoot production was maximized in the harvest months of March and April for J. nigra. Softwood shoot production was maximized in the harvest months of April and August for Q. rubra. Both shoot number and shoot length of softwood shoots decreased linearly with increasing BA concentrations applied to the branch segments of both species. Shoot production also decreased for both species during the dormant season September-December. The softwood shoots were surface disinfested and established on either 0 or 5µM Long Preece medium. When all BA treated softwood shoots were compared to the controls, the BA in the medium caused a significant increase in the number of shoots produced by explants obtained from the branch segments painted with BA. Painting with BA also increased shoot production in vitro, only if BA was also in the medium. Nodal explants cultured on 5µM LP medium taken from softwood shoots forced from branch segments painted with 3mM BA produced more shoots than any other BA concentration applied to branch segments except nodal explants on 5µM LP medium taken from softwood shoots forced from branch segments painted with 30mM BA.

Populus tremuloides Michx. (trembling aspen) is a tree species native to much of North America, characterized by an excurrent crown with horizontal to ascending branches and a dominant terminal leader. An unusual clone of trembling aspen was discovered in the 1940s near Hafford, Saskatchewan. This clone demonstrates abnormal crown morphology, in which vigorous shoots bend down, ultimately leading to an overall twisted or crooked appearance. The objectives of the present study were to investigate the mechanism of shoot bending by (1) characterizing the process and timing of bending, (2) evaluating structural aspects of developing wild-type and crooked aspen shoots, and (3) comparing anatomical features of bending shoots with wild-type shoots. L-system reconstruction models of 3-D digitized shoot development revealed dramatic bending midway through the growing season. Morphological analyses revealed that crooked aspen shoots had greater taper compared to the wild-type, typically known to create shoots resist deflection and bending. However, preliminary strength analyses indicated that crooked aspen shoots were less rigid, with smaller values of Young’s modulus compared to wild-type shoots. Anatomical investigations revealed differences in several structural tissues between developing wild-type and crooked aspen shoots, and differences within crooked aspen shoots. Primary phloem fibres on the upper side of bending shoots maintained relatively large lumens while those on the lower side were fully lignified, similar to those of mature vertically oriented wild-type leader shoots. These differences may result in differential extension growth early in development, and/or uneven mechanical support later on, ultimately resulting in bending due to self-weight. Gelatinous fibres (G-fibres), characteristic of tension wood (TW), were found throughout older wild-type and vertically oriented crooked aspen shoots; however, G-fibres were only found on the lower side of crooked aspen shoots. These lateral differences could have contributed to shoot bending by actively bending shoots downwards, or lack of TW on the upper side may not have prevented biomechanical bending from self weight. Nevertheless, shoot bending stops at the end of the growing season, suggesting that the mechanisms involved in creating bent shoots are only functional during the first growing season. / February 2006

Populus tremuloides Michx. (trembling aspen) is a tree species native to much of North America, characterized by an excurrent crown with horizontal to ascending branches and a dominant terminal leader. An unusual clone of trembling aspen was discovered in the 1940s near Hafford, Saskatchewan. This clone demonstrates abnormal crown morphology, in which vigorous shoots bend down, ultimately leading to an overall twisted or crooked appearance. The objectives of the present study were to investigate the mechanism of shoot bending by (1) characterizing the process and timing of bending, (2) evaluating structural aspects of developing wild-type and crooked aspen shoots, and (3) comparing anatomical features of bending shoots with wild-type shoots. L-system reconstruction models of 3-D digitized shoot development revealed dramatic bending midway through the growing season. Morphological analyses revealed that crooked aspen shoots had greater taper compared to the wild-type, typically known to create shoots resist deflection and bending. However, preliminary strength analyses indicated that crooked aspen shoots were less rigid, with smaller values of Young’s modulus compared to wild-type shoots. Anatomical investigations revealed differences in several structural tissues between developing wild-type and crooked aspen shoots, and differences within crooked aspen shoots. Primary phloem fibres on the upper side of bending shoots maintained relatively large lumens while those on the lower side were fully lignified, similar to those of mature vertically oriented wild-type leader shoots. These differences may result in differential extension growth early in development, and/or uneven mechanical support later on, ultimately resulting in bending due to self-weight. Gelatinous fibres (G-fibres), characteristic of tension wood (TW), were found throughout older wild-type and vertically oriented crooked aspen shoots; however, G-fibres were only found on the lower side of crooked aspen shoots. These lateral differences could have contributed to shoot bending by actively bending shoots downwards, or lack of TW on the upper side may not have prevented biomechanical bending from self weight. Nevertheless, shoot bending stops at the end of the growing season, suggesting that the mechanisms involved in creating bent shoots are only functional during the first growing season.

Populus tremuloides Michx. (trembling aspen) is a tree species native to much of North America, characterized by an excurrent crown with horizontal to ascending branches and a dominant terminal leader. An unusual clone of trembling aspen was discovered in the 1940s near Hafford, Saskatchewan. This clone demonstrates abnormal crown morphology, in which vigorous shoots bend down, ultimately leading to an overall twisted or crooked appearance. The objectives of the present study were to investigate the mechanism of shoot bending by (1) characterizing the process and timing of bending, (2) evaluating structural aspects of developing wild-type and crooked aspen shoots, and (3) comparing anatomical features of bending shoots with wild-type shoots. L-system reconstruction models of 3-D digitized shoot development revealed dramatic bending midway through the growing season. Morphological analyses revealed that crooked aspen shoots had greater taper compared to the wild-type, typically known to create shoots resist deflection and bending. However, preliminary strength analyses indicated that crooked aspen shoots were less rigid, with smaller values of Young’s modulus compared to wild-type shoots. Anatomical investigations revealed differences in several structural tissues between developing wild-type and crooked aspen shoots, and differences within crooked aspen shoots. Primary phloem fibres on the upper side of bending shoots maintained relatively large lumens while those on the lower side were fully lignified, similar to those of mature vertically oriented wild-type leader shoots. These differences may result in differential extension growth early in development, and/or uneven mechanical support later on, ultimately resulting in bending due to self-weight. Gelatinous fibres (G-fibres), characteristic of tension wood (TW), were found throughout older wild-type and vertically oriented crooked aspen shoots; however, G-fibres were only found on the lower side of crooked aspen shoots. These lateral differences could have contributed to shoot bending by actively bending shoots downwards, or lack of TW on the upper side may not have prevented biomechanical bending from self weight. Nevertheless, shoot bending stops at the end of the growing season, suggesting that the mechanisms involved in creating bent shoots are only functional during the first growing season.