本研究係利用澱粉膠體電泳探討臺灣赤楊(Alnus formosana(Burk.)Makino
)的族群遺傳結構。總共分析了15種同功酵素，記錄了23個基因座，其中多
型性基因座約佔46.2%；每一基因座之平均對偶基因數為1.8；所觀察到之
平均異質結合度(Ho)為0.181，符合哈溫定律之期望值(He)為0.175。族群
之遺傳歧異度有98%是存在族群之內，族群間的遺傳距離由0到0.019，族群
間分化的程度很低(Fst=0.038)，由自交係數(Fis=-0.057)可看出臺灣赤楊
族群是逢機交配且偏向異配生殖，族群間有充份的基因流傳(Nm=6.326)，
使得整個族群呈現均質化的現象。在不同海拔分佈的族群中，有七個基因
座之對偶基因頻率分佈呈現顯著的異質性，其中基因座SOD和PGM-1之對偶
基因頻率和基因型頻率的分佈，與海拔的變化呈現顯著的相關性。這些結
果顯示，臺灣赤楊族群分化的程度很低，可能是由於臺灣赤楊傾向異配生
殖且花粉和種子均由風力傳播，有足夠的基因流傳使族群呈現均質化的分
佈。臺灣赤楊是演替早期的物種，應具備較低的遺傳變異度，但因為其多
年生的特性，再加上可能的天擇作用之影響，使其族群內維持著相當高的
遺傳變異性。

Electrophoretically demonstrable diversity of 15 enzymes encoded
by a total of 23 structural loci was analyzed in 22 sexually
mature populations of Alnus formosana(Burk.) Makino (Betulaceae)
in Taiwan. On average, 46.2% of the loci per population were
polymorphic, with a mean of 1.8 alleles per locus. The observed
heterozygosity was not significantly different from expected
heterozygosity(Ho=0.181,He=0.175). Approximately 98% of the total
genetic diversity resided within populations. Genetic distance
between populations waslow, ranging from 0 to 0.019 with a mean
of 0.004. F-statistics showed very low differentiation between
populations (Fst=0.038). Inbreeding coefficient (Fis=-0.057)
revealed that non-assortative mating was common in this species.
Most populations however, appeared homogeneous, implying that
high level of gene flow occurred among populations them. On the
other hand, heterogeneity of allele frequencies among populations
along elevational gradient was noted at seven loci. The finding
that significant correlations between allelic frequences and
elevational gradient revealed at SOD and PGM-1 loci suggest that
genetic variation tends to be partially corresponded with
temperature changes. Low genetic differentiation among popula-
tions in Formosan alder may be attributed to the factors such as
mating system, pollen and seed dispersal. Differential selection
pressures and life-history seemed to be the main factors that
maintaining theobserved genetic variability of this species.
Electrophoretically demonstrable diversity of 15 enzymes encoded