| Summary: | 碩士 === 國立臺灣大學 === 生態學與演化生物學研究所 === 103 === Leaf margins of woody non-monocot angiosperms strongly correlate with their climatic distribution. Species in temperate mesic forests usually have leaves with toothed margins while species in tropical mesic forests have leaves with entire margins. The formation of leaf teeth may be caused by the space limitation of resting buds and leaf folding in buds during leaf development. Viburnum luzonicum like several other woody plants, has the preformed leaves developed in resting buds and neoformed leaves developed directly along shoots, therefore can be used to study the relationship between leaf shape and the appearance of resting buds when leaves developed.
Leafing phenology of deciduous shrub V. luzonicum in Balaka Road in Yangmingshan National Park (YMSNP, elevation 840 m), Mount Danfeng in Taipei City (elevation 120 m) and Taipei Botanical Garden (TPBG, elevation under 50 m) was studied here, and recorded for the life-span and shape of each leaves on the study branches. V. luzonicum exhibited one or two leaf flush in a growing season. The first flush is from February to April. All of the leaves in this flush are preformed leaves, which developed in resting buds of last growing season (winter buds). The second flush is after the flowering in March and April, and usually with a pair of preformed leaves (developed in resting buds in this growing season) and one to several pairs of neoformed leaves. In Mt. Danfeng and TPBG, 80.85% of tagged branches have second leaf flush, while 31.58% in YMSNP can have a second leaf flush. Leaves in second flush have less (42.67% of means teeth number of first flushing leaves) and shallower teeth, and a smaller leaf area (32.29% of means area of first flushing leaves). This study concluded that leaves developed in winter buds will have more toothed margin. Furthermore, leaves that have longer period in winter buds will also have more toothed margin.
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