Biological studies of Pteris fauriei complex (Pteridaceae)

• Main Authors: Yao-Moan Huang, 黃曜謀
• Other Authors: Jenn-Che Wang
• Format: Others
• Language: en_US
• Published: 2007
• Online Access: http://ndltd.ncl.edu.tw/handle/48852012932177292536

博士 === 國立臺灣師範大學 === 生命科學研究所 === 95 === Pteris fauriei Hieron. is a very common, evergreen fern in Japan, China, the Ryukyu Islands, Taiwan and Vietnam. In Taiwan, two taxa, P. fauriei var. fauriei and P. fauriei var. minor Hieron. have been documented. These two varieties can be distinguished based on spore size, the number of spores in each sporangium, the number of sperm in each antheridium, antheridium size, reproductive behavior, and the morphology of juvenile sporophyte fronds. Using spore size, the type specimens of P. fauriei var. fauriei and P. fauriei var. minor, collected by U. Faurie in 1904 and published by Hieronymus in 1914, are able to be confirmed as triploid and diploid, respectively. Based on spore sizes and the number of spore per sporangium, the distribution and habitats of the two cytotypes in Taiwan are characterized from both living plants and herbarium specimens. Diploid plants distribute widely in Taiwan and nearby islands, but do not occur in central Taiwan or in the Matsu islands. In contrast, triploid plants are not found in southern Taiwan or on islands west of central Taiwan. In general, triploids grow at higher elevation and cooler habitat than the diploids. Both varieties have the same atpB-rbcL non-coding spacer sequence. No genetic differentiation between these two varieties in terms of this DNA sequence. ISSR molecular data shows that most genetic variations occur among populations and few within populations. Despite the nature of obligate apomictic of P. fauriei var. fauriei is detected, however, there is relative higher genetic variation in this variety than that in the diploid variety. Recurrent and independent origins are considered the major source of genetic variation of the apomictic triploid P. fauriei var. fauriei. This study documents that triploid Pteris fauriei var. fauriei and diploid P. fauriei var. minor have differentiated various cryptic characteristics, significant separation of reproductive modes, and the preference of their distribution and habitats. However, the genotypes of the P. fauriei var. fauriei and var. minor do not distinctly separate from each other based on the genetic similarity derived from ISSR DNA markers.