Cytology of different species of palms and its bearing on the solution of the problems of phylogeny and speciation
01 Dec 1957-Genetica (Martinus Nijhoff, The Hague/Kluwer Academic Publishers)-Vol. 28, Iss: 1, pp 361-488
TL;DR: This document summarizes the main findings of a two-year investigation into the determinants of earthquake-triggered landsliding in Northern Ireland in the period of May 21-23, 1991.
Abstract: Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . 361 Materials and Methods . . . . . . . . . . . . . . . . . . . . . . 363 Observations . . . . . . . . . . . . . . . . . . . . . . . . . . 380 Discussions . . . . . . . . . . . . . . . . . . . . . . . . . . . 455 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . 483 References . . . . . . . . . . . . . . . . . . . . . . . . . . . 487
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TL;DR: Pollen-morphological groupings within the Palmae are compared with the taxonomic groupings of several authors and tentative taxonomic suggestions are made on the basis of pollen- morphological characters.
Abstract: This paper presents a pollen-morphological study of the Palmae. A total number of 350 species out of 120 genera were investigated. Pollen-morphological groupings within the family are compared with the taxonomic groupings of several authors and tentative taxonomic suggestions are made on the basis of pollen-morphological characters.
49 citations
TL;DR: The evolution of Chromosome Structure and the Origin of Agricultural Strains in Crop Plants and its Significance in Speciation are studied.
Abstract: Introducction 514 Types of Chromosomal Change in Relation to Speciation 516 Diminution in Chromatin as an Indication of Structural Changes in Chromosomes 518 Karyotypic Changes and the Origin of Agricultural Strains in Crop Plants 520 Fragmentation of Chromosomes as a Physical Basis of Speciation 521 A Tentative Suggestion Regarding the Evolution of Chromosome Structure 524 Inconstancy in Chromosome Complements within a Tissue and its Significance in Speciation 526 Conclusion 532 Further Research 534 References 5 35
46 citations
Cites background from "Cytology of different species of pa..."
...In one of the largest tropical families, the Palmeae, cytological investigations on which have recently been made ( 161 ), the same phenomenon is predominant in most of its members....
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01 Feb 1997
TL;DR: Nuclear DNA amounts are reported for 83 species and 53 genera of palms, covering all of the six subfamilies, and considerable variation occurs at the diploid level in some large and apparently actively evolving genera such as Chamaedorea, Pinanga, Cenoma and possibly Bactris.
Abstract: :
Nuclear DNA amounts are reported for 83 species and 53 genera of palms, covering all of the six subfamilies. 4C DNA contents range between 3.89 and 55.62 pg in diploids, showing an approximate 14.3-fold variation in genome size. Polyploids have DNA contents of up to 156.40 pg/4c which demonstrates a 40.2-fold variation. Diploids with high DNA contents occur in three subfamilies of palms (Coryphoideae, Calamoideae, Arecoideae), and seem to be further restricted to particular tribes or subtribes (Thrinacinae, Borasseae, Lepidocaryeae, Caryoteae, some subtribes of Areceae). Palms from the subfamilies Nypoideae and Phytelephantoideae have the lowest DNA amounts, followed by the Phoeniceae and the Corypheae: Livistoninae from the subfamily Coryphoideae. Although DNA amounts in some genera and subtribes are usually constant, e.g., in Phoenix, Phytelephas, the Livistoninae, Dypsidinae, diploid Butiinae), considerable variation occurs at the diploid level in some large and apparently actively evolving genera such as Chamaedorea, Pinanga, Cenoma and possibly Bactris. Formaldehyde fixation is recommended for palms, as conventional ethanol-acetic acid fixation has proved to be unsuitable for DNA estimation of Feulgen-stained nuclei by microdensitometry, since it can lead to errors up to 2.5-fold in extent. Chromosome counts are reported for 72 of the species studied, of which 42 are new.
42 citations
TL;DR: Karyological characters are compared to morphological, ecological, taxonomical, and chorological features, and give some new insight into older and more recent phases of palm evolution.
Abstract: Karyological data are given for 56 palm taxa coming from all 6 palm subfamilies. In 11 genera and 17 species, chromosome numbers are reported for the first time. Most chromosome numbers in palms range between 2n = 36 and 2n = 26 in dysploid series. Species of the same genus usually exhibit identical chromosome numbers which additionally may be constant in larger groups of closely related genera (Coryphoideae trib.Corypheae with nearly always 2n = 36,Arecoideae subtribesEuterpeinae andRoystoneinae with 2n = 36,Arecoideae subtrib.Butiinae with mostly 2n = 32). Polyploidy among palms is of minor significance but the endemic Madagascan genusVoanioala (2n = 606 ± 3) is the most striking exception. — With respect to structure of interphase nuclei and longitudinal differentiation of prophase and metaphase chromosomes, the palm family is highly differentiated. Euchromatin types with different prophase condensation properties and fluorochrome and C-banding patterns of heterochromatin permit a discrimination of several subfamilies on the nuclear level (Arecoideae, Ceroxyloideae, Nypoideae, Phytelephantoideae, Calamoideae).Arecoideae andCeroxyloideae, andNypoideae andPhytelephantoideae have some features in common. Subfam.Coryphoideae s. l. is a non-uniform group. — Nuclear characters among palms exclusively found in recentCoryphoideae subtrib.Thrinacinae link palms with other monocotyledons. Most probably, such a nuclear condition represents an ancestral state in the evolution of palm genomes within subfam.Coryphoideae s. l., but also the conspicuous nuclear characters of the other modern palm subfamilies appear to be derived from a similar starting point, since transitional character states are still present in subfam.Calamoideae and some taxa of subfam.Arecoideae. Early karyoevolution in palms obviously did not involve numerical change of the ancient chromosome number of 2n = 36 which started subsequently, as a dysploid reduction in numerous parallel series, independent in subfam.Coryphoideae (2n = 36 to 2n = 28),Calamoideae (2n = 36 to 2n = 26),Ceroxyloideae (2n = 34 to 2n = 26), andArecoideae (2n = 36 to 2n = 28). Possible mechanisms of karyological change are discussed. — Karyological characters are compared to morphological, ecological, taxonomical, and chorological features, and give some new insight into older and more recent phases of palm evolution. (1) Strong deviations in vegetative or floral morphology are often accompanied by major karyological differences, and sometimes the direction of advancement can be traced through intermediate stages. (2) Apart fromCoryphoideae subtrib.Thrinacinae, the strongest concentration of apparently original karyological traits is found in the more basal members of each subfamily. (3) The most successful and actively radiating colonizers of the forest floors in evergreen tropical forests which belong to completely different subfamilies (Old WorldLicuala, New WorldChamaedorea andGeonoma), appear to be very advanced karyologically.
42 citations
Journal Article•
TL;DR: A taxonomic account of the palm genus Livistona is presented and a neotype is proposed for L. saribus, and lectotypes are chosen for Lorophylla Becc.
Abstract: A taxonomic account of the palm genus Livistona is presented. Thirtysix species are recognised. Taxonomic and nomenclatural changes are applied to a number of species. Livistona rotundifolia (Lam.) Mart. is treated as a highly variable species, with L. rotundifolia var. luzonensis Becc., L. rotundifolia var. microcarpa (Becc.) Becc., L. rotundifolia var. mindorensis (Becc.) Becc. and L. robinsoniana Becc. placed as synonyms; L. fengkaiensis X.W.Wei & M.Y.Xiao is placed under L. speciosa Kurz; Livistona chinensis var. subglobosa (Hassk.) Becc. is placed under L. chinensis (Jacq.) R.Br. ex Mart.; Livistona tonkinensis Magalon is placed under L. saribus (Lour.) Merr. ex A.Chev.; and Livistona kimberleyana A.N.Rodd is placed under L. lorophylla Becc. A neotype is proposed for L. saribus, and lectotypes are chosen for L. altissima Zoll., L. beccariana Burret, L. hoogendorpii Hort. ex Teysm. & Binn. ex Miq., L. olivaeformis (Hassk.) Mart., L. subglobosa (Hassk.) Mart., L. tonkinensis Magalon, L. woodfordii Ridl., and Chamaerops biroo Siebold.
31 citations
Cites methods from "Cytology of different species of pa..."
...The morphological species concept by Stuessy (1990) and Kanis et al....
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References
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TL;DR: L'importanza delle modificazioni cromosomiche del soma nel problema della speciazione delle piante che si riproducono vegetativamente si delinea.
Abstract: RIASSUNTOL'A delinea l'importanza delle modificazioni cromosomiche del soma nel problema della speciazione delle piante che si riproducono vegetativamente
107 citations
TL;DR: The chromosomes of the male plants of 17 genera, 22 species and 2 varieties of dioecious phanerogams have been investigated and the following 13 forms show each an unequal pair of chromosomes in addition to autosome pairs at the meiotic division in microsporocytes.
Abstract: 1. The chromosomes of the male plants of 17 genera, 22 species and 2 varieties of dioecious phanerogams have been investigated. Of these the following 13 forms show each an unequal pair of chromosomes in addition to autosome pairs at the meiotic division in microsporocytes. This unequal pair of chromosomes is assumed to be a sex chromosome complex of an XY-type. Consequently in these forms the male plants are heterogametic with respect to sex. The 13 forms are Salix leucopithecia, S. sachalinensis, S. japonica, S. melanostachys, S. gracilistyla, S. viminalis var. yezonensis Morus bombycis, Cannabis sativa, Datisca cannabina, Daphniphyllum macropodum, Trichosanthes japonica, Hydrilla verlicillata and Trachycarpus excelsus.2. In Cudrania triloba, Acer negundo, Trachycarpus excelsus, var. Fortunei and Ginkgo biloba, one unequal pair-like pair is found at the first meiotic metaphase in microsporocytes; but it is not safe to take this for a true unequal pair of chromosomes until a further examination has been made.3. One large chromosome pair in Morus and Trachycarpus often divides in two unequal parts at the first meiotic division. The signifi-cance of this particular behaviour, especially in relation to sex determi-nation, is not yet known.4. Although many suitable figures of metaphase and anaphase of the first and second meiotic divisions in the male of Spinacia oleracea have been examined, no evidence of the existence of sex chromosomes has been obtained. An examination of the female has still to be undertaken.In microsporocytes of Aucuba japonica, 16 chromosomes are found at the first meiotic anaphase. The zygotic numbers of chromosomes in both sexes are the same, being 32. No evidence as to the sex chromo-somes could be obtained in the male plant.5. All Salix plants studied, except one form of S. sachalinensis, have 19 as the gametic chromosome number which is a basis in Salicaceae. The meiotic division is quite normal in them.One form of S. sachalinensis from Hokkaidoo has ca. 24 chromosomes at the first meiotic metaphase and their behaviour in the meiotic stages is irregular.6. Humulus japonicus, growing wild in the vicinity of Tokyo, has a tripartite chromosome in addition to 7 autosomic gemini at the first meiotic division in microsporocytes. At the first meiotic metaphase, the tripartite chromosome divides in such a way that the two end chromosomes go to the one pole, while the middle one goes to the other. Its behaviour is strikingly similar to that of Rumex acetosa. As a result, with respect to chromosomes, two kinds of pollen grains maybe formed. These results confirm that attained by KIHARA.7. Humulus lupulus has 10 gametic and 20 zygotic chromosomes. In the first meiotic division of microsporocytes, 16 chromosomes of the 20 form 8 gemini in all, while the 4 remaining chromosomes do not form gemini, but are connected end to end to form a beaded string. This tetrapartite chromosome can be identified in several stages from early diaphase, in the first meiotic division. At metaphase each alternate chromosome of the tetrapartite goes to opposite poles respectively. Thus the daughter nuclei receive an equal number of chromosomes, i.e. 10 respectively. The two middle members of a tetrapartite chromosome are equal in size and larger than the two end ones which differ in size from each other. As a result, two kinds of gametes may be formed, one having a larger amount of chromatin volume than the other. The tetrapartite chromosome may be a sex chromosome complex in H. lupulus, a new type of sex chromosome.8. At metaphase of the first meiotic division in the microsporocytes of Xanthoxylum piperitum, 35 chromosomes are counted, one of which is not only the largest
104 citations