Cytomixis and its possible evolutionary role in a Kuwaiti population of Diplotaxis harra (Brassicaceae)

Abstract

During a cytotaxonomical study of a Kuwaiti diploid (2n = 26) population of Diplotaxis harra (Forssk.) Boiss (Brassicaceae), cytomixis and aneuploidy were found in 1.5% and 7.8% of the pollen mother cells (PMCs), respectively. Cytomictic cells revealed wide variability as far as the number of involved PMCs and their stage of division were concerned. The cytoplasmic channels, which were of different sizes, contained migrating chromosomes in a few cases. In some PMCs, the location of some of the chromosomes was clearly indicative of an imminent migration from a donor to its attached recipient cell. At metaphase I and anaphase I, PMCs showed variable degree of chromosomal transfer. In addition to a genetic control of the phenomenon, stress factors such as high temperature or drought in certain periods of the growing season may have contributed to the incidence of cytomixis in the material. A possible relationship between cytomixis and detected aneuploid PMCs, as well as a reconsideration of an evolutionary role of cytomixis is discussed.

Morphological and Ecological Adaptations, and Cytological Studies in <i>Astragalus rhizanthus</i> Royle ex Benth. (Papilionaceae), an Endemic to Himalayas

“…Cytomixis induced meiotic irregularities and formation of hypo-and hyperploid PMCs has also been reported in several angiosperms (Omara 1976, Singhal and Gill 1985, Falistocco et al 1995, Malallah and Attia 2003, Ghaffari 2006, 2012, 2010, 2012, 2015, Singhal and Kumar 2008a, b, 2010, Singhal et al 2009, 2010, 2011a, b, 2014, Himshikha et al 2010, Kumar 2010, Kaur et al 2013, Rana et al 2013, 2014b, Mursalimov and Deineko 2011, 2012, 2015, Mursalimov et al 2013a. The phenomenon of cytomixis does not seem to have affected the pollen fertility to a greater extent in current case.…”

Phenomenon of Cytomixis and Intraspecific Polyploidy (2<i>x</i>, 4<i>x</i>) in <i>Spergularia diandra</i> (Guss.) Heldr. & Sart. in the Cold Desert Regions of Kinnaur District (Himachal Pradesh)

“…Similar findings on the impact of chromatin transfer in causing chromatin stickiness and consequently pollen sterility have been recorded earlier in Vicia faba (Haroun et al 2004), Caltha palustris , Meconopsis aculeata (Singhal and Kumar 2008a), Hippophae rhamnoides , Anemone rivularis (Singhal et al 2009a) and Clematis orientalis . The phenomenon of cytomixis has been reported in a large number of angiospermic plants, and many researchers consider cytomixis to be of considerable evolutionary significance (Falistocco et al 1995, Morikawa and Leggett 1996, Malallah and Attia 2003. Some of the possible causes and explanations put forth by earlier researchers include the effect of fixation (Haroun 1995), pathological changes (Morisset 1978), physiological control (Bahl and Tyagi 1988), chemicals and herbicides (Haroun 1995), environmental stress and pollution (Haroun et al 2004), temperature (Kumar and Tripathi 2008), stress factors and genetic control (Malallah and Attia 2003), pressure difference (Morisset 1978) and clumped chromatin bridges during premeiotic anaphase (Mendes and Rijo 1951).…”

“…The phenomenon of cytomixis has been reported in a large number of angiospermic plants, and many researchers consider cytomixis to be of considerable evolutionary significance (Falistocco et al 1995, Morikawa and Leggett 1996, Malallah and Attia 2003. Some of the possible causes and explanations put forth by earlier researchers include the effect of fixation (Haroun 1995), pathological changes (Morisset 1978), physiological control (Bahl and Tyagi 1988), chemicals and herbicides (Haroun 1995), environmental stress and pollution (Haroun et al 2004), temperature (Kumar and Tripathi 2008), stress factors and genetic control (Malallah and Attia 2003), pressure difference (Morisset 1978) and clumped chromatin bridges during premeiotic anaphase (Mendes and Rijo 1951). In the present case, cytomixis seems to be a natural phenomenon under direct genetic control as the plants with and without cytomixis grow under the same environmental conditions as reported by several researchers (Singhal and Gill 1985, Bellucci et al 2003, Haroun et al 2004, Lattoo et al 2006, Singhal et al 2007, 2009a, b, 2010, Singhal and Kumar, 2008a, b, 2010, b 2010, 2012, Himshikha et al 2010.…”

Evaluation of Interspecific-Interploid Hybrids (F1) and Back Crosses (BC1) in Hylocereus Species (Cactaceae)

“…This phenomenon was observed more frequently during microsporogenesis, mostly during Prophase of the meiotic division, but can occur in all stages of the meiosis, especially in genetically unbalanced genotypes such as haploids, triploids, aneuploids, mutants and hybrids (de Nettancourt & Grant, 1964;Gottschalk, 1970;Salesses, 1970;Mantu & Sharma, 1983). Usually, a few cells (two to four) participated in the process, while a large numbers of PMCs were involved (Malallah & Attia, 2003).…”