Karyomorphological studies in some Primula species of Nepal Himalaya.

Sakya, S. R.; Joshi, Kunjani

doi:10.1508/cytologia.55.571

Cited by 10 publications

(12 citation statements)

References 9 publications

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“…It has been proposed that polyploids have a greater resistance to the severe conditions found at high elevations, which may have promoted endemism at higher altitudes (Vetaas & Grytnes, 2002). There is a high polyploidy ratio among neoendemic vascular plant species both in the Himalaya and elsewhere (Kadota, 1987; Sakya & Joshi, 1990; Nayar, 1996; Solitis et al. , 1996).…”

Section: Discussionmentioning

confidence: 99%

“…It has been proposed that polyploids have a greater resistance to the severe conditions found at high elevations, which may have promoted endemism at higher altitudes . There is a high polyploidy ratio among neoendemic vascular plant species both in the Himalaya and elsewhere (Kadota, 1987;Sakya & Joshi, 1990;Nayar, 1996;Solitis et al, 1996). Natcheva & Cronberg (2004) report the existence of polyploidy in hepatics, and suggested that several isolating mechanisms that are recognized in flowering plants may possibly also occur in bryophytes.…”

Section: Endemismmentioning

confidence: 99%

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A comparison of altitudinal species richness patterns of bryophytes with other plant groups in Nepal, Central Himalaya

Grau

Grytnes

Birks

2007

Journal of Biogeography

182

135

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Aim To explore species richness patterns in liverworts and mosses along a central Himalayan altitudinal gradient in Nepal (100-5500 m a.s.l.) and to compare these patterns with patterns observed for ferns and flowering plants. We also evaluate the potential importance of Rapoport's elevational rule in explaining the observed richness patterns for liverworts and mosses.Location Nepal, Central Himalaya.Methods We used published data on the altitudinal ranges of over 840 Nepalese mosses and liverworts to interpolate presence between maximum and minimum recorded elevations, thereby giving estimates of species richness for 100-m altitudinal bands. These were compared with previously published patterns for ferns and flowering plants, derived in the same way. Rapoport's elevational rule was assessed by correlation analyses and the statistical significance of the observed correlations was evaluated by Monte Carlo simulations. ResultsThere are strong correlations between richness of the four groups of plants. A humped, unimodal relationship between species richness and altitude was observed for both liverworts and mosses, with maximum richness at 2800 m and 2500 m, respectively. These peaks contrast with the richness peak of ferns at 1900 m and of vascular plants, which have a plateau in species richness between 1500 and 2500 m. Endemic liverworts have their maximum richness at 3300 m, whereas non-endemic liverworts show their maximum richness at 2700 m. The proportion of endemic species is highest at about 4250 m. There is no support from Nepalese mosses for Rapoport's elevational rule. Despite a high correlation between altitude and elevational range for Nepalese liverworts, results from null simulation models suggest that no clear conclusions can be made about whether liverworts support Rapoport's elevational rule.Main conclusions Different demands for climatic variables such as available energy and water may be the main reason for the differences between the observed patterns for the four plant groups. The mid-domain effect may explain part of the observed pattern in moss and liverwort richness but it probably only works as a modifier of the main underlying relationship between climate and species richness.

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Section: Discussionmentioning

confidence: 99%

Section: Endemismmentioning

confidence: 99%

A comparison of altitudinal species richness patterns of bryophytes with other plant groups in Nepal, Central Himalaya

Grau

Grytnes

Birks

2007

Journal of Biogeography

182

135

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“…Bruun (1930, 1932) reported a diploid chromosome count of 2 n = 4 x = 44 in P. denticulata , whereas Sakya & Joshi (1990) recorded a series of 2 n = 22, 24, 32, 34 and 44 in Himalayan material of this species. Geographically, P. denticulata is native to China, where it is frequent in Guizhou, Sichuan, Xizang and Yunnan.…”

Section: Resultsmentioning

confidence: 99%

“…The diploid chromosome count of many species has been problematic, mainly because of great variations in ploidy levels (2 x to 14 x ), and sometimes there are conflicting reports for the same species. Examples are the reports of 2 n = 22, 44 (Bruun, 1930, 1932; Sakya & Joshi, 1990) and 32, 34 (Sakya & Joshi, 1990) for P. denticulata , 2 n = 18 (Bruun, 1930; Kress, 1963) and 36, 72 (Bruun, 1930, 1932) for P. frondosa , 2 n = 54 (Chiarugi, 1941), 62 (Wanner, 1943), 63 (Kress, 1989), 64 (Bruun, 1930, 1932) and 72 (Ernst & Moser, 1925) for P. hirsuta , and 2 n = 44 (Chiarugi, 1941, 1956; Garbari, 1974) and 66 (Kress, 1963, 1989) for P. palinuri . These are amongst the subject matter of this study.…”

Section: Introductionmentioning

confidence: 99%

“…Variation of chromosome number of Primula species, together with karyological analyses (Bruun, 1932; Kress, 1963; Favarger, 1965; Sakya & Joshi, 1990; Conti et al ., 2000; Mast et al ., 2001), represent fundamental steps towards our understanding of evolutionary trends in the genus, especially the relationships between ploidy level, biogeography and the origin of the basic chromosome number. However, studies of the karyological data in relation to interspecific and phylogenetic relationships in the genus are very limited.…”

Section: Introductionmentioning

confidence: 99%

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Chromosomal variability in the genus Primula (Primulaceae)

Abou-El-Enain

2006

Botanical Journal of the Linnean Society

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Chromosome numbers and measurements were recorded in 47 individuals of ten taxa of Primula , representing eight species and two subspecies from ten populations. The basic numbers of chromosomes were x = 8, 9 or 11, and they were mostly metacentric, medium-long to medium-small, ranging in length from c . 3.6 µ m to 1.6 µ m. Diploid chromosome numbers of 2 n = 2 x = 24 and 22 were scored for the first time in P. loeseneri Kitag. and P. prenantha Balf. & Sm., respectively. A new ploidy level of 2 n = 4 x = 44 was found in P. burmanica Balf. & King. The recorded diploid numbers of the remaining species confirmed earlier reports. Interspecific variability in chromosome numbers was correlated with heterogeneity in their mean length. Comparison of the data with those in the literature revealed that the observed variability of chromosomal characters was compatible with the other taxonomic criteria and supports the current taxonomic delimitation. Chromosomal variation at the diploid level is the predominant feature in Primula evolution, and allopatric speciation has played a major role in its specific diversity. Subgen. Aleuritia could represent the main clade from which the other subgenera have evolved. The origin of the chromosome numbers, geographical distribution and evolution of the species were assessed, and the parallel polyphyletic mode of evolution in the genus was confirmed.

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Angiosperm Diversity in Nepal

Bhandari

2024

Plant and Vegetation

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Karyomorphological studies in some Primula species of Nepal Himalaya.

Cited by 10 publications

References 9 publications

A comparison of altitudinal species richness patterns of bryophytes with other plant groups in Nepal, Central Himalaya

A comparison of altitudinal species richness patterns of bryophytes with other plant groups in Nepal, Central Himalaya

Chromosomal variability in the genus Primula (Primulaceae)

Angiosperm Diversity in Nepal

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