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)

Abstract

Summary Spergularia diandra (Guss.) Heldr. & Sart. (Family: Caryophyllaceae), worked out presently from the valleys of Ganjul and Hangrang in the Kinnaur district of Himachal Pradesh, exhibits intraspecific diploid (2x=n=9) and tetraploid (4x=n=18) cytotypes. The species has been worked out chromosomally for the first time from India and adds a new 4x cytotype to the already existing 2x cytotype known from outside of India. The individuals of 2x cytotype are restricted to the Ganjul Valley while those of 4x cytotype are present in Hangrang valley. The individuals of the 2x and 4x cytotypes could be distinguished on the basis of habit, plant size, number of branches, bushy nature, and fleshiness and size of leaves. The diploid plants showed spindle abnormalities during meiosis resulting into heterogeneous sized fertile/stained pollen grains and some pollen sterility (10.00-12.00%). On the other hand, some plants of 4x cytotype showed the phenomenon of cytomixis involving chromatin transfer among proximate meiocytes, and chromatin stickiness resulting into 5.00-8.00% unstained/sterile pollen grains. The cytomixis in the 4x cytotype is the first ever record for the species and seems to be a natural phenomenon under direct genetic control as the plants with and without cytomixis grow under the same environmental conditions.

First Report of Intraspecific Polyploidy (2<i>x</i>, 4<i>x</i>) in <i>Physochlaina praealta</i> (Decne.) Miers. (Family: Solanaceae)

“…All these factors could enable polyploids to be more competitive and potentially more invasive in a new environment (Pandit et al 2011(Pandit et al , 2014. Such an increase in the size of various vegetative and reproductive parts including micro-characters like stomata, trichome and pollen grains in the 4x individuals seems to be directly correlated with polyploidy and has been reported in a number of species, such as Terminalia chebula (Gill et al 1982), Syzygium cumini (Gill et al 1991), Centaurea stoebe (Spaniel et al 2008, Mráz et al 2011, Ranunculus hirtellus (Kumar and Singhal 2011), Galinsoga parviflora , Plantago depressa , Spergularia diandra (Kaur and Singhal 2012), Agrimonia eupatoria (Kumar et al , 2014a, Silene vulgaris (Kumar et al 2014b), and Tordyliopsis brunonis (Kumar et al 2014c).…”

Meiotic behavior and pollen fertility in triploid and tetraploid natural populations of Campuloclinium macrocephalum (Eupatorieae, Asteraceae)

“…Other authors considered also environmental effects, such as temperature and pollution (Basavaiah and Murthy 1987;Malallah and Attia 2003;Haroun et al 2004;Kumar and Tripathi 2008) and nutritional deficiency (Miljajev 1967). Recently, it has been suggested that the cytomixis is under gene(s) control (Mandal and Datta 2012;Kaur and Singhal 2012).…”

Cytomixis and Intraspecific Polyploidy (2<i>x</i>, 4<i>x</i>) in <i>Inula grandiflora</i> Willd. from Malana Valley, Kullu District, Himachal Pradesh

“…The 4x plants also possessed larger sized stomata and pollen grains. It is thus apparent that increase in plant height and size of leaves and capitula including micro-characters in 4x individuals is directly correlated with the increase in ploidy level as has been reported earlier in Terminalia chebula (Gill et al 1982), Syzigium cumini (Gill et al 1991), Centaurea phrygia (Kouteckỳ 2007), Centaurea stoebe (Spaniel et al 2008, Mraz et al 2011, Galinsoga parviflora (Bala et al 2011), Parasenecio auriculata (Nakagawa 2006), Ranunculus hirtellus (Kumar and Singhal 2011), Spergularia diandra (Kaur and Singhal 2012), Agrimonia eupatoria , Kumar et al 2014a, Silene vulgaris (Kumar et al 2014b) and Tordyliopsis brunonis (Kumar et al 2014c).…”