Cytomorphological Diversity in Some Members of Family Asteraceae from the Ecologically Disturbed Habitats of Solang Valley, Kullu District, Himachal Pradesh

Kaur, Maninder; Singhal, Vijay Kumar

doi:10.1508/cytologia.80.203

Cited by 7 publications

(5 citation statements)

References 68 publications

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“…Present count of diploid chromosome number (2n=18) in the studied accessions supports the earlier chromosome reports by Shetty (1964), Mehra et al (1965), Mehra and Remanandan (1974), Mathew and Mathew (1988), and Gupta and Gill (1989), Kaur and Singhal (2015), and Rana et al (2015) from different parts of India and by a number of workers from outside of India. Achillea millefolium which constitutes a species complex having 2x, 3x 4x, 5x, 6x and 8x cytotypes (based on x =9) is one of the most extensively studied species from N-W Himalayas.…”

Section: Discussionsupporting

confidence: 88%

Occurrence of Syncytes: A Possible Mechanism Owing to the Origin of Polyploid Cytotypes in <i>Achillea millefolium</i> L. within Indian Himalayas

2017

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Present study records the existence of tetraploid and hexaploid meiocytes and subsequently the formation of large and very large-sized pollen grains for the first time in the diploid individuals of Achillea millefolium. In majority of the diploid accessions, meiocytes exhibited nine bivalents, equal segregation of chromosomes during anaphases, regular tetrads and normal-sized n pollen grain formation. In the accessions scored from Palchan (2400 m) and Dhundhi (3050 m) regions of Solang Valley, two to three proximate PMCs fused during early stages of Prophase-1 and Metaphase-1 resulting into tetraploid (4x) and hexaploid (6x) meiocytes with 18 and 27 bivalents, respectively. Although the frequency of polyploid PMCs was rather low these are detectable due to their larger size compared to diploid PMCs. In both the accessions, the diploid and polyploid PMCs exhibited the multiple chromosomal associations of four to eight chromosomes indicating the existence of structural heterozygosity. Analysis reveals that there is an increase in the chiasma frequency with structural heterozygosity for reciprocal translocations. Syncyte meiocytes followed a regular meiotic course resulting into the formation of normal tetrads but the products of such sporads yielded atypical (large and very large-sized) pollen grains compared to normal sized typical pollen grains. Although the exact cytological status of aforesaid pollen grains could not be ascertained but such fertile larger-sized pollen grains with possible 2n or 3n genetic constitution might be involved in fertilization to generate polyploid offsprings and the origin of intraspecific polyploid cytotypes (4x, 6x) which are known to exist in some populations of Himalayas in India.

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Section: Discussionsupporting

confidence: 88%

Occurrence of Syncytes: A Possible Mechanism Owing to the Origin of Polyploid Cytotypes in <i>Achillea millefolium</i> L. within Indian Himalayas

2017

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“…But a diploid form of S. oleraceus (2n= 16) and tetraploid (2n= 32) were previously reported by Marchal (1920) and Cooper & Mahony (1935), respectively. More studies had described S. asper as diploid (2n= 18) and S. oleraceus as tetraploid (2n= 32) (Turner et al 1961;Walter & Kutta 1971;Boulos 1972;Hsieh et al 1972;Gupta & Gill 1983;Sidhu et al 2011;Kaur & Singhal 2015). The variation of chromosome number in Sonchus species points towards the incidence of aneuploidy that has happened over time in the genus Sonchus.…”

Section: Resultsmentioning

confidence: 99%

A cytomorphological investigation of three species of the genus Sonchus L. (Asterales: Asteraceae) from Punjab, India

Sidhu

Singh

2021

J. Threat. Taxa

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Three species of the genus Sonchus L. (Sonchus asper, S. oleraceus and S. wightianus) were collected from the Malwa region of Punjab during 2019 to 2020. These species were studied for cytomorphological variations. The species under investigation were identified based on their morphological descriptions. Sonchus asper (L.) Hill and Sonchus wightianus DC. possess the same number of chromosomes (2n=2x=18) whereas Sonchus oleraceus (L.) L. is tetraploid with 2n=4x=32 chromosomes. Chromosome number of S. wightianus (2n=2x=18) was worked out for the first time from the state of Punjab. Sonchus olereceus has larger pollens than S. asper and S. wightianus. This study will be useful for researchers, taxonomists and cytologists for accurate identification of these three species.

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“…This phenomenon detected in the meiocytes of several plants can cause variation in the chromosome number. However, this variation can be prevailing in populations of wild-type (Kaur and Singhal, 2015), having the form of different types of aneuploidy (trisomy, tetrasomy, double trisomy) or polyploidy (diploid, triploid, tetraploid, octaploid). Tetrasomy can be the origin that explains this variability (2n=20: no tetrasomy, 2n=22: one chromosome tetrasomy, 2n=24: two tetrasomy chromosomes).…”

Section: Chromosome Numbersmentioning

confidence: 99%

Flow cytometry and chromosome numbers variation in argan tree Argania spinosa (L.) Skeels

et al. 2023

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Argania spinosa L. Skeels is an endemic species of west-central Morocco, which is characterized by a high diversity of morphological and genetic traits. It constitutes a natural resource for oleo-agro-sylvo-pastoral uses. All conservation and genetic breeding strategies aimed to domesticate argan require a good knowledge of the plant material. However, several studies focused on agronomical, morphological, phytochemical, and molecular characterization, while the cytogenetic aspects were less investigated. The objective of this work is to identify the chromosome number and ploidy level on the national argan collection at the Agadir Regional Agronomic Research Center, Morocco. The determination of the chromosome number was carried out on root tips of germinated seeds collected from five trees genotypes selected on various morphological aspects. As a result, chromosome count on active root tip cells showed variation in the number (2n = 20; 2n = 22; 2n = 24) with a stable ploidy level (2n = 2x) that is confirmed by flow cytometry. These results combine two previous findings (2n=20, 2n=24) and reveal a third existence of twenty-two chromosome. As a conclusion, A. spinosa has three chromosomal numbers which represent the genetic diversity of the chromosomal number that this species exhibits. More studies are required to explain this variation on chromosome numbers for future breeding programs and to avoid incompatibilities.

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Cytomorphological Diversity in Some Members of Family Asteraceae from the Ecologically Disturbed Habitats of Solang Valley, Kullu District, Himachal Pradesh

Cited by 7 publications

References 68 publications

Occurrence of Syncytes: A Possible Mechanism Owing to the Origin of Polyploid Cytotypes in <i>Achillea millefolium</i> L. within Indian Himalayas

Occurrence of Syncytes: A Possible Mechanism Owing to the Origin of Polyploid Cytotypes in <i>Achillea millefolium</i> L. within Indian Himalayas

A cytomorphological investigation of three species of the genus Sonchus L. (Asterales: Asteraceae) from Punjab, India

Flow cytometry and chromosome numbers variation in argan tree Argania spinosa (L.) Skeels

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