The cytology of two varieties of Polyanthes tuberosa with special reference to their inter-relationship and sterility
01 Dec 1957-Genetica (Martinus Nijhoff, The Hague/Kluwer Academic Publishers)-Vol. 28, Iss: 1, pp 99-111
TL;DR: Relationship between the two varieties of Polyanthes luberos a and the relationship and taxonomic position of Agaveae is described.
Abstract: Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . 99 Materials and Methods . . . . . . . . . . . . . . . . . . . . . . 101 Observations . . . . . . . . . . . . . . . . . . . . . . . . . . 102 1. Karyotype analysis . . . . . . . . . . . . . . . . . . . . . 102 2. Meiosis . . . . . . . . . . . . . . . . . . . . . . . . . . 104 3. Cause of sterility . . . . . . . . . . . . . . . . . . . . . . . 105 Discussion . . . . . . . . . . . . . . . . . . . . . . . . . . . 107 1. Relationship and taxonomic position of Agaveae . . . . . . . . . 107 2. Relationship between the two varieties of Polyanthes luberos a . . . 108 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1 0 References . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 I0
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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
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01 Feb 1971
TL;DR: Bimodality and permanent anorthoploidy inOnosma are compared with similar phenomena in other plant species.
Abstract: This study is concerned with the karyology ofOnosma, and partly with related morphological and taxonomical problems. 24 species and subspecies, and l new hybrid have been considered. New or corrected chromosome numbers as well as new combinations and emendations are shown on the table p. 229. Some species have large (L-) and small (K-) chromosomes, some, additional B-chromosomes. Aberrant pairing in PMC meiosis is indicated by Roman numbers.
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29 citations
TL;DR: The present investigation clearly points out the chromosomal causes of sterility and makes possible a reinterpretation of the non-recovery of recombinant phenotypes and the occurrence of albina and other mutations in hybrid progenies.
Abstract: Pachytene analysis was undertaken in 4 japonica-indica rice hybrids. In all these hybrids, pairing was exceedingly abnormal lending evidence for structural hybridity. Earlier investigators who analysed metaphase-I and later stages of meiosis concluded that sterility is due to genic causes. The present investigation clearly points out the chromosomal causes of sterility and makes possible a reinterpretation of (1) non-recovery of recombinant phenotypes and (2) the occurrence of albina and other mutations in hybrid progenies.
26 citations
01 Aug 1961
TL;DR: The present study lends support to Nandi’s hypothesis that the basic chromosome number of the genus is 5 and indicated that the karyotypes of wild species, O. australiensis, are more symmetrical than those of the cultivated species,O.
Abstract: The karyomorphology ofOryza australiensis, O. glaberrima andO. stapfii was investigated at the pachytene stage. It was found that the twelve chromosomes of all the three species are identifiable by the lengths, arm ratios and chromomeric pattern. A detailed description of each of the bivalents is given. The bivalents ofO. australiensis are considered to be more heterochromatic than those of the other two species. The present study indicated that the karyotypes of wild species,O. stapfii andO. australiensis, are more symmetrical than those of the cultivated species,O. glaberrima andO. sativa. The present study lends support to Nandi’s hypothesis that the basic chromosome number of the genus is 5. The karyotype ofO. australiensis is distinct by aggregation of chromomeres and the absence of supernumerary nucleoli.
5 citations
References
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1,036 citations
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: Are sex chromosomes in higher pl,~nt~ nucleologenic?
Abstract: Introduction . M~t~rial and methods 0 bservations: Cucumis a~giz,u~ . Cucumis Memo Trichoaanth~ diolca Luffa aegyp~i~c,a . Luffa a~u~an~u~a . 6'o~iuia indica Beuincasa cerifera M~,mrdica cllarantia Cucurbita ~r~aarima Polysomaty Discussion (i) Numerica! correlation between m a~m um number ofnucleoli, sat~llltes and secondary constrictions (ii) Maximum number of nucleo]i ,lnd nucleolar constrictions of chromosomes witah reference to polyplcidy and aneuploidy . . . {iii) Variation of chromosome number in Cucm.bitaceac and R~. cytogsnetic interpretation (iv} Are sex chromosomes in higher pl,~nt~ nucleologenic? . Summary P, efsrsnces P A G ~
100 citations
Journal Article•
90 citations
"The cytology of two varieties of Po..." refers background or methods in this paper
...Another genus Bravoa, examined by SATO (1938) has also 2n = 60 chromosomes and Polyanthes tuberosa (single), as has been noted, also possesses the same number....
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...…attempts will now be made to show far HUTCHINSON'S opinion is acceptable with regard to the tribe Agaveae to which Polyanthes tuberosa be-10I~gs. SATO (1938) determined the chromosome numbers of twelve species of the genus Agave and found that the number is always a multiple of thirty, ranging…...
[...]
...SATO (1938) on the basis of the numbers and general appearance of the somatic chromosomes of about a dozen species of Agaveae and of one species of each of the genera Polyanthes and Bravoa supported HUTCHINSON'S contention and concluded that Agavaceae stands apart sharply from Amaryllidaceae and…...
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...…behaviour during meiosis of the two common varieties of Polyanthes tuberosa, if compared with the corresponding data obtained from the family Amaryllidaceae (Cf. previous paper and also SATO, 1938) might provide evidence of a more convincing nature with regard to the systematic status of Agaveae....
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...The need of cytological data with respect to the structure and behaviour of chromosomes in solving taxonomical problems is being more and more felt in recent years (SATO, 1937, 1938 ; BABCOCK, 1942 ; LONGLEY, 1942; WILKINSON, 1944; BHADUKI i~nd BOSE, 1947)....
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TL;DR: All genera except Haernanthus in the Amaryllidoideae may be concluded to have some karyotypical resemblances, when the karyotype alteration such as fusion, fragmentation, duplication, translocation, inversion, elimination and deficiency have been taken into consideration.
Abstract: (1) The karyotypes of nineteen genera in the Amaryllidoideae, namely Haerrzanthus (2n=16, 18), Grij inia (2n=77), Clivia (2n=44), Galanthus (2n=24, 25, 28, 48), Leucojum (2n=14, 22), Nerine (2n=22, 33), Amaryllis (2n=22), Zephyranthes (2n=12, 24, 38), Sternbergia (2n=22) Crirzum (2n=22, 33), Cyrtanthus (2n=22) Eucharis (2n=68), Hymenocallis (2n=46, 69), Narcissus (2n=14, 21, 22, 32), Paracratium (2n=44), Sprekelia (2n=ca. 117), Hippeastrum (2n=44), Habranthus (2n=21) and Lycoris (2n=27) have been analyzed from the point of karyotype alteration (cf. Table 1). Many genera such as Grinia, Clivia, Leucojum, Nerine, Amaryllis, Stervbergia, Crinum, Cyrtanthus, Pancratiurn, Hippeastrunz, Habranthus and Lycoris have the 11-series of chromo-somes, in the ether word 11 is their basic number of chromosomes which indicates the intimate relationship existing between these karyotypes. More striking is the fact that various karyotypes be-longing to the same genus, for instance Leucojutm (b=7, 11), have been explicitly explained by the dislocation hypothesis of Navashin (1932). By further reference to this hypothesis it may be possible to suggest the derivaticn of karyotypes in other genera.(2) The karyotypes of Hymenocallis (2n=46, 69) and Eucharis (2n=68) clearly indicate their derivation from the 11-series by the duplication of chromosomes and the secondary balance. The similar secondary polyploid appeared in Zephyranthes (b=6), i.e., Z. candicla (2n=38). All genera except Haernanthus in the Amaryllidoideae may be concluded to have some karyotypical resemblances, when the karyotype alteration such as fusion, fragmentation, duplication, translocation, inversion, elimination and deficiency have been taken into consideration. The karyotypes of Haemanthus resemble those of Scilla in the Liliaceae or Alstroemeria in the Hypoxidoideae.(3) The karyotypes of five genera in the Agavoideae, namely Bravoa, Polianthes, Agave, Fourcroya, and Beschorneria are similar (so-called the Yucca-Agave karyotype) (5 long and 25 short chromo-somes) (cf. Table 2). The karyotype of Dorjanthes (4 long and 44 short chromosomes) is different from the Yucca-Agave type, but some similarities are suggested, although difference in chromosome sizes can clearly be detected. The karyotypes of the Agavoideae are generally speaking different from other ones in the Amaryllidaceae and rather resemble those of Yuccae in the Liliaceae.(4) The karyotypes of Alstroenteria (2n=11) and Bornalia (2n=18) in the Hypoxidoideae are similar to those of Haemanthus (2n=16), especially in respect to the SAT-chromosomes.(5) The hypothesis of the SAT-chromosome has been adopted in the present analysis of karyotypes in the Amaryllidaceae and has brought about successful results. Various hypotheses of karyotype alteration were discussed and such karyotype alterations are con-cluded to be genotypically controlled (cf. Levitskij 1937). The genotypic control of karyotype alteration and the secondary balance seem to play an important role in the process cf evolution.(6) The relation between the nucleoli and the SAT-chromosomes was discussed and the hypothesis of the SAT-chromosome was extended to reconcile it with the conception of the nucleolar chromosome. The presence of the SAT-chromosome was emphasized by the observation of satellites or secondary constrictions in many species which had usually been overlooked cr neglected by previous investigators.The writer wishes to express his thanks to Ass. Prof. Y. Sinoto under whose direction this investigation has been carried out.
89 citations