Meiotic Studies of Some Stipa (Poaceae) Species and Populations in Iran

Abstract

Meiotic studies were performed on 11 populations of 8 Stipa species concerning polyploidy level, chiasma frequency and distribution, chromosomes association and segregation. All the species and populations studied possessed nϭ22 (2nϭ4xϭ44) chromosome number. The chromosome numbers of 3 species are reported for the first time. The populations and species studied differed significantly in their meiotic characteristics. Meiotic abnormalities observed included laggard chromosome formation, stickiness and cytomixis. Cytomixis led to the formation of aneuploid meiocytes. Unreduced pollen grains were observed in 2 species, which differed significantly in their size compared to the normal (reduced) pollen grains.

Meiotic Studies in Some Members of Caesalpiniaceae R. Br. from the Western Himalayas (India)

“…The cytomixis, chromosomal stickiness, laggards, and bridges among the presently studied species at the population level indicate the existence of intraspecific genetic diversities. Such genetic differences have been observed earlier in different plant species by Baptista-Giacomelli et al (2000) and Sheidai et al (2003).…”

Cytogenetics of Four Species of Genus <i>Berberis</i> L. (Berberidaceae Juss.) from the Western Himalayas

“…Cytomixis or the occurrence of multipolar cells and meiotic irregularities in anaphase segregation of chromosomes may be the possible mechanisms for the formation of large-sized pollen grains and low pollen fertility in these meiotically abnormal populations as has been reported earlier in several angiospermic plants (Sheidai et al 2008, Jeelani et al 2011, Rani et al 2012. The production of hypo-and hyperploid PMCs due to cytomixis (Falistocco et al 1995, Sheidai and Bagheri-Shabestarei 2007, Fadaei et al 2010 accompanied by other meiotic abnormalities lead to anomalous microsporogenesis, resulting in the formation of variable-sized pollen grains, possibly with an aneuploid condition and low pollen fertility (Villeux 1985, Nirmala and Rao 1996, Sheidai and Fadael 2005, Sheidai et al 2003. The formation of large-sized pollen grains as seen at present is in accordance with previous information about the possibility of such pollen grains resulting from unreduced 2n pollen grains as has been observed in several angiosperms by Vorsa and Bingham (1979), Bertagnolle and Thomson (1995), Sheidai et al (2008), Fadaei et al (2010) and Jeelani et al (2011).…”

Cytomixis and Associated Meiotic Abnormalities in Pollen Mother Cells of <i>Chlorophytum tuberosum</i> (Roxb.) Baker

“…Although this phenomenon has been reported, in various plants, by earlier researchers (e.g. Gottschalk 1970, Cheng et al 1975, Omara 1976, Premachandran et al 1988, Peng et al 2003, Zhoushi 2003, Sheidai and Attaei 2005, Sidorchuk et al 2007, its occurrence in C. tuberosum has been recorded for the first time in this paper.…”