Controversy on the origin of angiosperms and gymnosperm s evolution What recent molecular have told us 1) about the evolution seed plants 2) why the evolutionary trees of extant gymnosperm has to be redrawn? Morphology of extant gymnosperms Relationship among the orders and families 3) why the evolutionary position of Gnetales has to be reconsidered. Demise of the anthophyte hypothesis (Doyle & Donoghue 1987) Gnetales probably is sister to Pinaceae (Chaw et al. 2000) 4) about the evolution of angiosperms.
顯花植物的起源和裸子植物演化的爭論 最近的分子證據告訴了我們 1) 關於種子植物的演化 2) 為什麼現生裸子植物的演化樹需要修訂 現生裸子植物的形態特徵 現生裸子植物各目各科之親緣關係新解 3) 買麻藤目的親緣地位需要重新定位 anthophyte hypothesis (Doyle & Donohue 1987) 成立否? 買麻藤目可能是松科的姊妹群 4) 顯花植物的演化
Extant gymnosperms 現生裸子植物 (4 orders; 16/17 families; 730 species) Cycadales 蘇鐵目 : 200+ spp. Cycaceae 蘇鐵科 (Zamiaceae, Stangeriaceae) Ginkgoales 銀杏目 : 1 spp. Ginkgoaceae 銀杏科 (Ginkgo biloba) Gnetales 買麻藤目 : Gnetaceae, Ephedraceae, Welwitschiaceae 買麻藤科 (30+ spp.) 麻黃科 (40 spp.) 千歲蘭科 (1 sp.) Coniferales 松柏目 : 500+ spp. Pinaceae 松科 (230 + spp.) Phyllocladaceae 枝葉科 Podocarpaceae 羅漢松科 Araucariaceae 南洋杉科 Sciadopityaceae 金錢松科 Taxaceae 紅豆杉科 Cephalotaxaceae 粗榧科 Taxodiaceae 杉科 Cupressaceae 柏科 (100+ spp.)
van Gelderen DM & JRP. van Hoey Smith. CONIFERS. 1992. 呂勝由攝 van Gelderen DM & JRP. van Hoey Smith. CONIFERS. 1992.
van Gelderen D M & J. R P van Hoey Smith. CONIFERS. 1992.. van Gelderen D M & J. R P van Hoey Smith. CONIFERS. 1992.
呂勝由攝 van Gelderen D M & J. R P van Hoey Smith. CONIFERS. 1992.
Page CN (1990) Coniferphytina. In kramer KU & Green PS (eds.) The Families and Genera of Vascular Plants. Vol.1. p. 385. Springer-Verlag, Berlin
by Y Qiu
琉球松 紅豆杉
具單胚珠毬果
Paraphyletic view Angiosperms were derived from certain gymnosperms: (* based on morphological & fossil data) Bennetatiales* (Arber & Parkin 1907, 1908) Glossipteridales* (Melville 1969; Retallack & Dichler 1981) Caytoniales* (Cronquist 1988) Gnetales (Wettstein 1907) * Mesozoic gymnosperms
Monophyletic view None of the extant gymnosperms is a direct ancestor of angios. Hori et al. (1985) -5S rrna seqs Troistky et al. (1991) -5.8S& partial 18S rrna seqs of nucleus & plastids Hasebe et al. (1992) - rbcl gene seqs Goremykin et al. (1996) - cp ITS seqs
Polyphyletic view - seed plants Beck (1981 and references therein) Aneurophytales Archaeopteridales Meyen (1984) Cycadopsids Coniferopsids Ginkgoopsida - progymnosperms, ginkgo, & Ephedra Pinopsida - dervied from Cycadopsida Mesozoic Mesozoic cordaites, cordaites, the the conifers conifers & ginkgo ginkgo Cycads, Cycads, Gnetum Gnetum Welwitschia, Welwitschia, angiosperms, angiosperms, seed seed ferns ferns
Monophyletic view - seed plants Rothwell (1981, 1982) Aneurophytes Pteridophytes Gymnosperms Archaeopteridales is unrelated to any of seed plants. The seed originated only once
The above molecular data were based on a few gymnosperm samples partial rrna or plastid sequences analysis including the saturated synonymous sites (Martin et al. 1993; Goremykin et al. 1996)
Phylogenetic analysis Sequence alignment Calculation of distance matrix (Kimura 2P method, 1980; Ts/Tv= 0.4/0.6) Tree reconstruction: outgroup -Sellaginella i) Neighbor-joining method (Saito & Nei 1980) ii) Parsimony method: using PAUP 3.1.1 (Swofford 1993) - Heuristic search Relative rate test (Wu & Li 1985)
Objectives reconstruct phylogenetic relationships of Seed plants and Extant gymnos. orders & families examine hypotheses - Seed plant evolution Evol. position of Gnetales study the Range of rate variation
Albert et al. (1983) Molecualr Biology of the Cell. 3 rd edn. Garland Publ., Inc. New York
從 18S rrna 序列重建現生裸子植物之親緣關係
RESULTS In gymnosperms - 3 monophyletic clades Cycadales-Ginkgoales, Gnetales, Coniferales None of the extant gymnosperm is a direct ancestor of the angiosperms We rejected Gnetales & Angios. are sister groups Diversification of modern gymnosperm orders occurs after they split from angiosperms
DISCUSSION Ginkgo is closer to cycads than to Coniferales/Genetales Cycads-Ginkgo clade is the basal gymnosperm lineage Refute Page s (1990) classification: Coniferphytina: ginkgo & conifers Cycadophytina: cycads & the Gnetales Reject Savard et al. s proposal (1994, p. 5166): conifers & cycads form a clade that represents the earliest seed plant lineage.
CONCLUSIONS Extant seed plants share a common ancestor - the seed evolved only once. The angiosperms & gymnosperms are two separate lineages. Within the gymnosperms there are three monophyletic clades:
從 18S rrna 序列重建現生裸子植物之親緣關係
CONCLUSIONS - within conifers - Pinaceae is monophyletic & basal to the remaining conifer families. - Among the latter there are monophyletic clades: Phyllocladaceae-Podocarpaceae- Araucariaceae, & Sciadopityaceae-Taxaceae-Cephalotaxaceae- Taxodiaceae-Cupressaceae. - Sciadopityaceae is an outgroup to Taxaceae-Cephalotaxaceae- Taxodiaceae-Cupressaceae
Chaw et al. 2000
Appendix 1. Summary of Cretaceous leaf and pollen sequences. Note pollen sequences from monosulcate to triporate types and primitive angiosperms leaf types in the Barremian Aptian (after Stewart & Rothwell, 1993; Fig. 30.6)
Appendix 2. Change in diversity, at the species level, of suprageneric taxa represented in the late Mesozoic and Cenozoic Eras (after Stewart & Rothwell, 1993; Fig. 32.3). Portrait of Charles C. Darwin,1840
Combined 18S rdna, rbcl, & atpb seqs. Soltis PS et al. (1999) Nature 402: 402-404
Acknowlegement Research Grants National Science Foundation Institute of Botany,Academia Sinica, Taiwan People & Organization for Materials (Method or Unpublished Sequences*). D. E. Bouford, C.-Y. Chen, T.-Y. Chiang, J. R. Haller, M. Hasebe, H. Keng, R. Nicolson, T.-P. Lin, C.-I. Peng, D. E. Soltis*, T. Takaso, H. Tobe, K. Trapp, Q.-Y. Xiang