The seven New Zealand species of Schoenus (Cyperaceae) with holocentric chromosomes were analysed by staining their chromosomes with CMA₃/DAPI for fluorochrome banding. Variability in the banding pattern was found among the species studied. Fluorescence in situ hybridization was used to locate ribosomal DNAs and Arabidopsis-type telomeric sequences. Variation in the number of rDNA signal sites was observed, although the position of these sites was conserved. The Arabidopsis-type (TTTAGGG)_n telomeric sequences hybridized on both ends of all chromosomes.

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Heavy metals are ubiquitous in nature. Toxicity of metals depends upon their optimum level in environment. Chromosomal plant assay is an important tool for the estimation of genome damaging property of the pollutants above the optimum level. In the present investigation on ajwain (Trachyspermum ammi (L.) Sprague), cyto-chromotoxicty was evaluated in terms of reduced mitotic activity and various mitotic irregularities comprising scattering, stickiness, precocious movement, laggards, bridges, c-mitosis, etc. Five concentrations (50, 75,100,150 and 200 ppm) of both the metal salts (Pb(NO₃)₂ and Cr₂O₃) were used. Dose dependent increase in the chromosomal aberrations and decrease in mitotic indieces were observed. On comparing mitotoxicity of both the metals, Pb was more growth inhibitory and mitotoxic than Cr.

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Male meiosis and pollen fertility have been studied in 31 angiospermic species belonging to 29 genera and eight families. During meiotic course, ten species are found to have anomalous meiotic course exhibiting the abnormalities in varying frequencies as Capillipedium assimile (chromatin stickiness, cytomixis), Phacelurus speciosus (chromatin stickiness, laggards, bridges, unoriented bivalents), Lolium remotum (cytomixis, laggards, bridges, micronuclei), Sisymbrium strictum (cytomixis, laggards, bridges), Ranunculus hyperboreus (cytomixis, laggards, bridges, micronuclei), Impatiens scabrida (laggards, bridges and abnormal microsporogenesis), Pennisetum alopecuroides (laggards and bridges), Phalaris minor (laggards, bridges, unoriented bivalents), Dactylis glomerata (late disjunction of bivalents). These abnormalities results in the reduction of pollen fertility of the plants.

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The present investigation involves the meiotic studies on two populations of Calamagrostis emodensis Griseb. (Family: Poaceae) from District Kinnaur, Himachal Pradesh, India in the Western Himalayas. Both the populations reveals tetraploid chromosome count of 2n=28 which is the first ever report for the species. The objective of the present research were to study the detailed meiotic course, microsporogenesis, and the effect of meiotic abnormalities encountered during different stages of meiosis I and II on pollen grain size and pollen fertility.

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The present study shows the chromosome numbers of Tanacetum parthenium with 14 populations and eight populations both in Hamedan Province, Iran. In this study, the two species showed intraspecific polyploidy. Among the populations of T. parthenium studied eight populations showed the chromosome number of 2n=2x=18, while five populations showed 2n=4x=36, that confirmed the previous results. Additionally, a population showed the hexaploid chromosome number of 2n=6x=54. According to the documentation of the chromosome numbers of Tanacetum, the present count of hexaploid was the very first recording for T. parthenium. In all populations the basic chromosome number was x=9. Also in this study, mitotic chromosome number for eight populations of Tanacetum polycephalum were reported; in two populations of this species showed the chromosome number of 2n=4x=36 and six populations confirmed the previous count of , chromosome number was 2n=4x=36. six populations confirmed the previous count of n=6x=54.

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