A synopsis of the cytogenetics of the genusPhlomoides(Lamiaceae) in Iran

Abstract

The present study reports the chromosome number and meiotic behavior of 11 populations belonging to four species of Phlomoides (L.) Moench. All populations showed the diploid chromosome number 2n = 2x = 22; consistent with the proposed base number of x = 11. Almost all taxa studied here displayed regular bivalent pairing and chromosome segregation at meiosis. However, meiotic abnormalities observed included varied degree of fragmented chromosomes, laggards and bridge in anaphase I to telophase II, precocious division of centromeres, asynchronous nucleus and cytomixis. In addition, a survey on chromosome counts of different species belonging to the genus Phlomoides throughout the world is presented and the base chromosome numbers and polyploidy levels discussed here.

Cytological Studies in Endangered <i>Phlomoides superba</i> (Royle ex Benth.) Kamelin & Makhm.

“…Azizian and Cutler (1982) stated that polyploid was not so common in the genus Eremostachys (Phlomoides) suggesting a base number of x=11. Based on the published chromosome counts (2n=12, 14, 21, 20, 22, 24, 28, 42, 46, and 88) available for the species of genus Phlomoides and 2n=22 the most represented count in the genus, Ranjbar et al (2016) also suggested x=11 as the basic number for the genus. In acceptance with the previous reports and the current report, it can be said that the P. superba occurs at diploid level (2x) in its entire range from Afghanistan to Uttar Pradesh in India.…”

“…The most prominent deviation from normal meiotic behavior in the currently studied species is out of plate bivalents and early disjunction which can be due to spindle abnormalities. The chromatids/chromosomes are attached to the spindles with kinetochores which help to keep it in the desired orientation for uniform distribution of chromosomes at the poles (Ranjbar et al 2016). Normally bipolar spindle is responsible for this process.…”

“…However, cytological studies remain confined to merely a chromosome of n=11 from type locality ʻMohandʼ (Dhawan and Gupta 1983) and Afghanistan (Podlech and Dieterle 1969). Only 17-19% of species in the genus have chromosome numbers reported (Ranjbar et al 2016). To better understand various mechanisms operative in the evolution of a particular species, chromosomal studies are quite useful.…”

Biology of Flowering of Some Species of the Genus &lt;i&gt;Phlomoides&lt;/i&gt; Moench

“…Research on taxonomy, molecular phylogeny of Phlomoides species can be seen in the works of Salmaki [3], Ranjbar [4], Komarevseva [5], Gulomov [6].…”