Induced Tetraploidy in &lt;i&gt;Vinca rosea&lt;/i&gt; Linn

Dnyansagar, V. R.; Sudhakaran, I. V.

doi:10.1508/cytologia.35.227

Cited by 19 publications

(11 citation statements)

References 10 publications

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“…Deleterious effects of univalents on meiotic course and pollen fertility have also been documented by several workers (Singhal 1982;Fiona et al 1988;Leggett 1998;Datta 2009a, 2009b;Datta et al 2010;Goyal and Khan 2010). On the other hand, Dnyansagar and Sudhakaran (1970) in Vinca rosea, Merker (1971) in Triticale, Gatt et al (2000) in some hybrids of Dahlia, and Palma-Silva et al (2004) in Vriesea and Aechmea showed that frequency of univalents is not correlated directly with reduced pollen viability. Among the other reasons put forth to explain the reduction in chiasma frequency, Hultén (1974) argued that terminalization of chiasmata occurs when there is contraction of the bivalents during diakinesis which may reduce chiasma frequency.…”

Section: Discussionmentioning

confidence: 96%

Reduction in chiasma frequency and pollen fertility due to multiple chromosomal associations and univalents inSaxifraga diversifoliafrom alpine regions of northwest Himalayas (India)

Kumar

Singhal

2013

Caryologia

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Two varieties of Saxifraga diversifolia, diversifolia and parnassifolia, collected from the moist alpine slopes around Gauri Kund, 3930 m (Manimahesh Hills, Himachal Pradesh, India), are studied for detailed male meiosis, chiasma frequency and pollen fertility. Both varieties exist at diploid level (based on x = 8), and show a meiotic chromosome count of n = 8 at diakinesis and metaphase-I, and regular chromosome distributions at anaphases-I/II. The meiotic chromosome count of n = 8 ascertained here represents a new aneuploid cytotype, supplementing the earlier report of a diploid cytotype with 2n = 20 from the northwest Himalayas in India and the Nepal Himalayas. Of the two varieties, var. diversifolia showed the presence of multiple chromosomal associations and univalent chromosomes at diakinesis and metaphase-I of meiosis-I. On the other hand, var. parnassifolia does not have multivalent formation but showed only 2-4 univalent chromosomes at diakinesis and metaphase-I. Occurrence of univalents in pollen mother cells of var. diversifolia and parnassifolia reduced the chiasma frequency significantly and also caused some pollen sterility (7-8%). The paper herein discusses for the first time the occurrence of structural heterozygosity and univalent chromosomes and their apparent affect on chiasma frequency and pollen fertility in S. diversifolia.

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Section: Discussionmentioning

confidence: 96%

Reduction in chiasma frequency and pollen fertility due to multiple chromosomal associations and univalents inSaxifraga diversifoliafrom alpine regions of northwest Himalayas (India)

Kumar

Singhal

2013

Caryologia

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“…The deleterious effect of univalents on pollen stainability observed in S. impressa has been documented by Simonsen (1972) in Phleum pratense, and by Fiona et al (1988) in Solanum muricatum. However, Dnyansagar and Sudhakaran (1970) in Vinca rosea, Merker (1971) in Triticale, Gatt et al (2000) in some hybrids of Dahlia, and Palma-Silva et al (2004) in Vriesea and Aechmea demonstrated that the frequency of univalents is not correlated with pollen stainability. Furthermore, the deleterious effect of chromosome bridges in anaphase I on pollen stainability observed in S. impressa has been documented by Gustafsson (1972) in Atriplex longipes, by Sisodia (1971) in Urochloa, by Spies et al (1992) in Tribolium, Lu (1993) in Elymus, by Atlagić (1996) in Helianthus, Costa and Forni-Martins (2004) in Echinodorus tennellus.…”

Section: Discussionmentioning

confidence: 97%

“…Such studies include those by Dnyansagar and Sudhakaran (1970) in Vinca rosea, Merker (1971) in Triticale, Gatt et al (2000) in some hybrids of Dahlia, and Palma-Silva et al (2004) in Vriesea and Aechmea.…”

Section: Introductionmentioning

confidence: 99%

Cytogenetics, Geographical Distribution, Pollen Stainability and Fecundity of Santolina impressa (Asteraceae: Anthemideae)

Rivero-Guerra

2009

Folia Geobot

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Santolina impressa (2n = 2x = 18) is an endemic species of Portugal, with restricted geographical distribution. The present study aimed to explore its chromosomal variation in respect to chromosome morphology, meiotic behaviour, and effects on pollen stainability and fecundity. Its karyotype formula was found to be either 12m + 2m sat + 2sm sat + 2st (75% of the individuals) or 12m + 2m sat + 3sm + 1sm sat (25% of the individuals). Univalents were observed in 29.21% of the meiocytes. Chromosome fragments due to breakage in the chromosome arm were observed in 10 meiocytes only (11.23% of the meiocytes). Chains and rings of trivalents were observed in 14.60% of the meiocytes (one trivalent per meiocyte was observed). Chains and rings of quadrivalents were observed in 21.34% and 11.23% of the meiocytes, respectively, with a range of 0-1 per cell. Nine plants (40.90% of the total) with 2n = 2x = 18 + 2B showed a quadrivalent configuration in diakinesis. Twenty abnormal anaphases with delayed disjunction of the four nonhomologous and the two homologous chromosomes were observed. Simple chromosome bridges without fragments and interchromosomal adhesions were observed in 35.95% of the anaphases analyzed. B chromosomes showed bivalent association in diakinesis and their segregation at anaphase I was normal. Pollen was found to be fertile (mean ± s.d. = 89.57 ± 47.14%); the effect of univalent frequency and frequency of abnormal anaphase I on pollen stainability was strong and statistically significant.

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“…The chromosome number of all species of the genus Catharanthus is 2 n = 16 [ 9 , 21 , 22 ] with a genome size of 1500 Mbp (van Iren, unpublished). Doubling of chromosome number, tetraploidy, has been induced by colchicine treatment that resulted in an increase in TIAs, larger stomata, branches, and leaves, although there was reduced pollen fertility and poor seed set compared with diploid plants [ 23 , 24 ].…”

Section: Geneticsmentioning

confidence: 99%

Ornamental Exterior versus Therapeutic Interior of Madagascar Periwinkle (Catharanthus roseus): The Two Faces of a Versatile Herb

Nejat

Valdiani

Cahill

et al. 2015

The Scientific World Journal

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Catharanthus roseus (L.) known as Madagascar periwinkle (MP) is a legendary medicinal plant mostly because of possessing two invaluable antitumor terpenoid indole alkaloids (TIAs), vincristine and vinblastine. The plant has also high aesthetic value as an evergreen ornamental that yields prolific blooms of splendid colors. The plant possesses yet another unique characteristic as an amiable experimental host for the maintenance of the smallest bacteria found on earth, the phytoplasmas and spiroplasmas, and serves as a model for their study. Botanical information with respect to synonyms, vernacular names, cultivars, floral morphology, and reproduction adds to understanding of the plant while the geography and ecology of periwinkle illustrate the organism's ubiquity. Good agronomic practices ensure generous propagation of healthy plants that serve as a source of bioactive compounds and multitudinous horticultural applications. The correlation between genetic diversity, variants, and TIA production exists. MP is afflicted with a whole range of diseases that have to be properly managed. The ethnobotanical significance of MP is exemplified by its international usage as a traditional remedy for abundant ailments and not only for cancer. TIAs are present only in micro quantities in the plant and are highly poisonous per se rendering a challenge for researchers to increase yield and reduce toxicity.

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Induced Tetraploidy in <i>Vinca rosea</i> Linn

Cited by 19 publications

References 10 publications

Reduction in chiasma frequency and pollen fertility due to multiple chromosomal associations and univalents inSaxifraga diversifoliafrom alpine regions of northwest Himalayas (India)

Reduction in chiasma frequency and pollen fertility due to multiple chromosomal associations and univalents inSaxifraga diversifoliafrom alpine regions of northwest Himalayas (India)

Cytogenetics, Geographical Distribution, Pollen Stainability and Fecundity of Santolina impressa (Asteraceae: Anthemideae)

Ornamental Exterior versus Therapeutic Interior of Madagascar Periwinkle (Catharanthus roseus): The Two Faces of a Versatile Herb

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