Chromosome Number, Meiosis and Pollen Fertility in Vicia rigidula Royle and V. tenera Grah. from Cold Desert Regions of India

Abstract

SummaryWe have recorded the meiotic chromosome counts in 2 species, Vicia rigidula (nϭ12) and V. tenera (nϭ7) from the cold desert region of Kinnaur district of Himachal Pradesh (India). V. rigidula which exists at tetraploid level (xϭ6) and depicts the phenomenon of cytomixis involving chromatin transfer in 6.52% of the observed pollen mother cells (PMCs) during different meiotic stages. 3.43-12.20% of PMCs also show non-synchronous disjunction of a few bivalents, laggards and chromatin bridges during anaphases/telophases, and micronuclei and included micronuclei in tetrads. Products of such aberrant PMCs result in the formation of sterile/unstained pollen grains and fertile/stained pollen grains of variable sizes. The meiotic course in V. tenera, which is diploid (xϭ7), depicts normal meiotic behaviour in the majority of the PMCs. Only a few PMCs (0.20-1.20%) depict some meiotic disturbances during anaphases resulting in the formation of 6.00-7.20% sterile/unstained pollen grains. Key words Chromosome number, Cytomixis, Meiotic irregularities, Vicia rigidula, V. tenera.The genus Vicia L., Tribe: Vicieae, Family: Fabaceae with 190 species (ILDIS 1999) is distributed in Europe, Asia and North America, extending to the temperate regions of South America and Tropical Africa (Maxted 1993). In India species of the genus Vicia are distributed in the temperate zones of Western Himalaya and the Northern plains. Many species of the genus are cultivated for food and fodder (Cremonini et al. 1998). Maxted et al. (1991) have divided the genus Vicia into 2 subgenera: Vicilla and Vicia with 17 and 9 sections, respectively. Most of the species of the genus are annuals, but a few of them are perennials. V. rigidula Royle is a perennial subglabrous climber with 2-3 inch long leaves ending in intricate tendrils and with golden yellow flowers appearing during June to September. The species is found in the temperate regions of Western Himalaya between altitudes of 1500-3000 m. V. tenera Grah. grows as a perennial subglabrous climber with pinnate leaves and pinkish-purple flowers which appear during May-July. The species is distributed at elevations of 1800-2600 m in moist shady places.Perusal of chromosomal data on the basis of information gathered from Index to Plant Chromosome Numbers and other authors (Srivastava 1963, Raina and Bisht 1988, Kumari and Bir 1990, Nikiforova 1990, Maxted et al. 1991, Venora et al. 1991, Akpinar and Bilaloglu 1997, Bisht et al. 1998, Kamel 1999, Bagci and Sahin 2000, Kotseruba et al. 2000, Rahiminejad et al. 2000, Tabur et al. 2000, 2002 reveals that a large number of species of the genus Vicia are yet to be known chromosomally, especially those from the high altitudinal regions and cold deserts of Indian Himalayas. We have worked out the chromosome counts in V. rigidula and V. tenera collected in Kinnaur district of Himachal Pradesh. Simultareously, we have also recorded our observations on male meiotic course, pollen sterility and pollen grain size in these species.

Syncytes during male meiosis resulting in 2n pollen grain formation in Lindelofia longiflora var. falconeri

“…A number of genotypes with different levels of abnormal meiotic behavior caused by extreme cold and xeric conditions have been evaluated in the plants of cold deserts of Pangi Valley, Chamba District, Himachal Pradesh. Already a large number of meiotic irregularities due to cold stress conditions affecting pollen size and fertility have been detected in the plants of the cold deserts of Lahaul‐Spiti and Kinnaur District of Himachal Pradesh (Kumar & Singhal, 2008; Kumar et al, 2008, 2010, 2011; Singhal & Kumar, 2008, 2010; Singhal et al, 2008, 2009; Singhal & Kaur, 2009; Kaur & Singhal, 2010). In the present study we report the occurrence of syncyte formation due to the fusion of two PMCs during the early stages of prophase I in L. longiflora , whereas the fusion of more than two cells forming syncytes have also been recorded in Brachiaria decumbens Stapf and Brachiaria jubata (Fig.…”

Morpho-meiotic study in Mentha longifolia from cold desert regions of Lahaul-Spiti and adjoining areas of Himachal Pradesh (India)

“…In the presently studied species, intraspecific morphological variation was reported in different cytotypes of M. longifolia L. (n = 9, 12). Intraspecific morphological variation in the populations of M. longifolia (Table 1) might be attributed to the variation in chromosome numbers (n = 9, 12) and abnormal meiotic course, as it has been reported earlier in large number of flowering plants, e.g., Centaurea phrygia (Koutecký 2007), Centaurea stoebe (Španiel et al 2008), Ranunculus parnassifolius (Cires et al 2009), Agrimonia sp., Geranium wallichianum, Ranunculus hirtellus and Vicia rigidula (Kaur and Singhal 2010a). The presence or absence of B-chromosomes did not affect the morphological characteristics as the plants of M. longifolia with or without B-chromosome are indistinguishable in most of their descriptor states.…”

Meiotic behavior of two grapevine somatic mutants with ornamental potential

“…Thus, as laggard chromosomes and precocious chromosome segregation in diploid accessions of Musa spp. (Adeleke et al, 2004) and in Mesosetum chasaea (Silva et al, 2012), or as laggard chromosomes and bridges in Vicia rigidula (Kaur and Singhal, 2010) and in Trigonella pubescens (Kaur et al, 2013). It is likely that the high percentage of laggard chromosomes and of precocious chromosome segregation observed in 'Variegada', could have resulted of a precocious chiasma terminalization, while a high percentage of non-oriented chromosomes may have been due to a failure in an accurate attachment of the chromosome kinetochore to the spindle fibers.…”