Altitudinal Variation of Resin Ducts in Pinus Taiwanensis Hayata (Pinaceae) Needles
Resource
Botanical Bulletin of Academia Sinica 44 (4): 305-313
Journal
Botanical Bulletin of Academia Sinica
Journal Volume
44
Journal Issue
4
Pages
305-313
Date Issued
2003
Date
2003
Author(s)
Chiou-Rong Sheue, Yuen-Po Yang
Abstract
The variation of resin ducts in needles of Pinus taiwanensis along an altitude gradient (700 m- 3,100 m) in central Taiwan is revealed for the first time in this study, including position type, number, size, arrangement pattern and anatomical structural variation. Three types of resin ducts-medial, external and septal-were found according to their relative positions in the mesophyll. All needles sampled showed combinations of these three resin duct types. Mostly, 3-7 resin ducts were found in the mesophyll per needle, and the number of resin ducts was significantly greater at mid altitudes than at high and low altitudes. Septal ducts decreased in number with an increase in altitude; however, needles from mid altitudes had more external ducts. Eight patterns (basic and patterns I-VII) of resin ducts in the mesophyll of needles were delineated to present the arrangement variations. In addition to the primary ducts found in the mesophyll, we found the rare bundle sheath ducts in some needles, and their frequencies decreased obviously with an increase in altitude. The consistent combination feature of medial, external, and septal ducts in needles of P. taiwanensis from Taiwan could be easily distinguished from those with medial ducts from mainland China. However, this difference has unrecognized before, and it should be considered in future taxonomic work.
SDGs
Publisher
中央研究院植物研究所
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