Ploidy dimorphism and reproductive biology in Stenodrepanum bergii (Leguminosae), a rare South American endemism

Genome ◽  
2012 ◽  
Vol 55 (1) ◽  
pp. 1-7 ◽  
Author(s):  
Irene Caponio ◽  
Ana M. Anton ◽  
Renée H. Fortunato ◽  
G.A. Norrmann
Keyword(s):  
Reproductive Biology ◽  
Chromosome Numbers ◽  
Reproductive Behaviour ◽  
South American ◽  
Chromosome Counts ◽  
Central Western Argentina ◽  
Sexual Cross ◽  
Aneuploid Chromosome ◽  
Rare Endemic ◽  
Two Populations

This is the first report on chromosome numbers and the reproductive behaviour in Stenodrepanum Harms, a rare endemic and monotypic legume genus from the arid and salty areas of central–western Argentina. Sixty individuals belonging to two populations from two salty areas (“salinas”) were surveyed and included mostly triploid (2n = 3x = 36) and only two diploid (2n = 2x = 24) plants. Meiosis in diploids is regular, with bivalent pairing and uniform and viable pollen. In contrast, meiosis in triploids is characterized by high trivalent pairing, with irregularly shaped pollen and variation in cytoplasm content and stainability, which is in agreement with an unbalanced segregation occurring in anaphases I and II. However, different triploid plants/individuals showed various degrees of pollen fertility, which may be attributed to particular genotypes. Research on reproductive biology events indicates sexual cross-pollinated reproduction enhanced by protogyny in both cytotypes. All plants produced seeds, but seedlings were only recovered from diploid plants pollinated with triploids, and even those eventually perished. Chromosome counts in these seedlings revealed aneuploid chromosome numbers owing to the combination of unbalanced gametes.

Life history and taxonomy of two populations of ligulate Desmarestia (Phaeophyceae) from Chile

1986 ◽  
Vol 64 (12) ◽  
pp. 2948-2954 ◽  
Author(s):  
M. E. Ramirez ◽  
D. G. Müller ◽  
A. F. Peters
Keyword(s):  
South Africa ◽  
Life History ◽  
Chromosome Numbers ◽  
Taxonomic Status ◽  
Southern Chile ◽  
Northeast Pacific ◽  
Laboratory Cultures ◽  
Monoecious Population ◽  
Two Populations

Two populations of broad-bladed (ligulate) Desmarestia from central and southern Chile were studied in laboratory cultures. They differ in sporophyte morphology and gametophyte characters (monoecism versus dioecism). The dioecious population is found to be related to D. firma from South Africa and D. munda from the northeast Pacific, while the taxonomic status of the broad-bladed monoecious population is left undetermined. In both populations sporophytes originate after fertilization as well as by apomixis. Chromosome numbers alternate between ca. 23 and ca. 46. Evidence is presented that spermatozoids of the dioecious Desmarestia can develop into sporophytes (androgenesis or ephebogenesis).

Chromosome numbers, meiotic behavior, and notes on tropical American grasses (Gramineae)

1974 ◽  
Vol 52 (2) ◽  
pp. 317-328 ◽  
Author(s):  
Gerrit Davidse ◽  
Richard W. Pohl
Keyword(s):  
Chromosome Numbers ◽  
Meiotic Behavior ◽  
Chromosome Counts

Chromosome numbers and meiotic behavior are reported for 126 collections of grasses representing 50 genera and 111 species. First counts are given for the genera Leptothrium, n = 10, and Cryptochloa, 2n = 22 (somatic count). First chromosome counts are given for the following 25 species: Aristida recurvata, n = 11; Axonopus laxus, n = 20; Chloris mollis, n = 20; Chusquea longifolia, n = 20; Cryptochloa concinna, 2n = 22; Digitaria abyssinica, n = 18; Eragrostis airoides, n = 36; E. guianensis, n = 10; Eriochloa boxiana, n = 18; Gymnopogon foliosus, n = 10; Leptothrium rigidum, n = 10; Luziola pittieri, n = 12; L. spruceana, n = 24; Otachyrium inaequale, n = 10; Panicum cayennense, n = 27; P. chloroticiun, n = 18; P. schiffneri, n = 18; Pappophorum pappiferum, n = 30; Paspalum apiculatum, n = 10; P. arundinaceum, n = 30; P. contractum, n = 9; P. coryphaeum, n = 30; P. trachycoleon, n = 20; Setaria barbata, n = 27; and Trisetum foliosum, n = 28. Counts that differ from previously reported counts are given for the following 15 species: Axonopus chrysoblepharis, n = 10; Cenchrus brownii, n = 34; Digitaria horizontalis, n = 9, 27; Echinolaena gracilis, n = 10; Euclasta condylotricha, n = 10; Hyperthelia dissoluta, n = ca. 30; Ischaemum guianense, n = 18; Microchloa indica, n = 12; Paspalum candidum, n = 10; P. melanospermum, n = 20; P. prostratum, n = 10; Rhytachne rottboellioides, n = 16; Setaria paniculifera, n = 16; Sorghastrum incompletum, n = 20; and Thrasya petrosa, n = 30. Changes in nomenclature are indicated for Digitaria species whose chromosome numbers were reported in our earlier publications.

New chromosome numbers for rutaceae

1992 ◽  
Vol 5 (4) ◽  
pp. 501 ◽  
Author(s):  
HM Stace ◽  
JA Armstrong
Keyword(s):  
Chromosome Numbers ◽  
Pollen Sterility ◽  
Chromosome Counts ◽  
Cytological Data ◽  
Taxonomic Implications

Chromosome counts for 30 taxa, representing five genera, are reported for Rutaceae subfamily Rutoideae, mostly in the Australasian tribe Boronieae. We found n = 10 for Boronia algida which is previously unreported in the genus, and a sterile triploid taxon in Zieria. Generic chromosome numbers of n = 18 in Zieria, n = 16 in Phebalium and n = 14 in Eriostemon sens. lat. occur, while Boronia shows cytoevolution on n = 18, 11, 10, 9. Pollen sterility and possible apomixis is indicated in some species. Some taxonomic implications of cytological data in the tribe Boronieae are discussed.

The mating system and genic diversity in Martínez spruce, an extremely rare endemic of México's Sierra Madre Oriental: an example of facultative selfing and survival in interglacial refugia

2000 ◽  
Vol 30 (7) ◽  
pp. 1156-1164 ◽  
Author(s):  
F Thomas Ledig ◽  
Basilio Bermejo-Velázquez ◽  
Paul D Hodgskiss ◽  
David R Johnson ◽  
Celestino Flores-López ◽  
...  
Keyword(s):  
Mating System ◽  
High Frequency ◽  
Expected Heterozygosity ◽  
Sierra Madre ◽  
Fixation Indices ◽  
Rare Endemic ◽  
Genic Diversity ◽  
Total Genic Diversity ◽  
Two Populations ◽  
Nei's Genetic Distance

Martínez spruce (Picea martínezii T.F. Patterson) is a conifer currently passing through a bottleneck, reduced to a few relict populations totaling less than 800 trees. We used isozyme markers to analyze the mating system and survey the level of genic diversity in two populations. The mating system was characterized by a high frequency of selfing. The multilocus outcrossing rates (tm) and 95% confidence intervals were only 0.399 (0.197 < tm < 0.601) for the smallest population and 0.589 (0.475 < tm < 0.703) or 0.685 (0.465 < tm < 0.905), depending on year, for the largest. These are among the lowest rates of outcrossing observed in conifers. The fixation indices for the two populations were -0.058 and 0.121, less than expected for such high levels of selfing. Expected heterozygosity, unbiased He, based on 22 loci in 13 enzyme systems, was 0.121 and 0.101 in the two populations. The proportion of the total genic diversity between populations, FST, was 2.4%. Nm, the number of migrants per generation, was about 1.00 or 10.17, depending on the method of estimation. The time since the two populations were isolated was estimated from Nei's genetic distance as only 150 to 15 000 years, which is consistent with a hypothesis of population collapse during late Pleistocene or Holocene warming. We discuss the implications for conservation.

Aneuploidy Alnus formosana Selection and ISSR Analysis

2014 ◽  
Vol 998-999 ◽  
pp. 177-182
Author(s):  
Heng Xing Zhu ◽  
Ding Jie Yi ◽  
Jiaia Tang ◽  
Xiao Hui Huang ◽  
Guo Lu Liang ◽  
...  
Keyword(s):  
Chromosome Numbers ◽  
Drying Method ◽  
Issr Analysis ◽  
Aneuploid Chromosome

the chromosomal counting was carried out with 51 of annual Taiwan alder (Alnus formosana) by the wall degradation and hypotonic flame-drying method, and 6 aneuploid plants has been selected from these seedings. The viable aneuploid chromosome numbers included 2n=52 (No.4),2n=42 (No.19),2n=54(No.21),2n=50(No.24),2n=56,112 (No.25),2n=52(No.33). Subsequently, the ISSR was taken to analyze the genome of these aneuploid plants,and 5 primers were obtained from 57 which could separate 6 aneuploid plants. And the ratio of polymorphism was more than 78.2%.

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