Research on Grafting Variation of Terminalia boivinii

• Main Authors: Guan-Ru Peng, 彭冠儒
• Other Authors: 章錦瑜
• Format: Others
• Language: zh-TW
• Published: 2009
• Online Access: http://ndltd.ncl.edu.tw/handle/64614374589620101434

碩士 === 東海大學 === 景觀學系 === 97 === At present, Terminalia boivinii has been widely planted throughout Taiwan, which is considered as a prevalent and new plant species for the past twenty years. Some of the adult trees are bred from the grafted nursery stocks, whose rootstock is Terminalia catappa As the times goes by, these grafted stocks have grown into big trees, which also exhibit obvious grafting variation. In addition to particular swelling at the callus, the rootstock is notably thinned and shrunk, and the tree trunks are no longer straight or upright. Grafted branch would have different bark colors on the upper and lower parts. Since the lower part is Terminalia catappa, its bark is distinctly dark brown. The root may form buttress. The main purpose of this study is to investigate the current growing state of the grafted Terminalia boivinii, understand the variation of grafting on Terminalia boivinii, compare the difference between grafted and non-grafted Terminalia boivinii, and predict the possible problems of grafted stocks. This study was based on on-site investigation, and the research area was National Chung Cheng University and Taichung City. The results showed that the grafted Terminalia boivinii is likely to form buttress, and the size of buttress is much larger, in length, thickness, and height, than non-grafted samples. Terminalia boivinii with rootstock of Terminalia may easily form large buttress. Also, the position of the callus may affect the percentage of trunk thinning and shrinking. Comparison of the diameter of trunk showed that, as the grafting position is lower, the trunk thinning and shrinking is less obvious. The position of callus would affect the thickness and height of the rootstock. When the height difference of the callus of callus (height difference of horizontal cutting is zero), the thickness and height difference of the rootstock is also smaller. The results proved that the grafting produces variation, notably the rootstock thinning and shrinking, which may be more serious as the tree grows. The thinning and shrinking branch on tall Terminalia boivinii may likely to break, thus leading to collapse. Therefore, it is suggested to avoid using grafting to breed landscape trees. If grafting is necessary, the grafting position should be as low as possible so that the root grafting would not have obvious thinning and shrinking. In addition, the grafting should adopt horizontal cutting, instead of oblique cutting, so that the trunks can retain straight and upright. For the grafted Terminalia boivinii whose trunks are obviously thinned and shrunk, it is suggested to cut off the tree top to reduce its height and strengthen its strut, in order to avoid the risk of sudden collapse.