Chromosome number and morphology in 14 taxa belonging to 19 populations of Tripleurospermum Sch. Bip. were studied using karyological and numerical taxonomical techniques. Data on chromosome measurements were analysed using cluster analysis. Chromosome numbers of these taxa are 2 n = 2 x = 18, 4 x = 36 and 5 x = 42-48. Seven records are new, two are not consistent with previous counts, and the remainder confirm the very limited previous data (one to three records). A new ploidy level (pentaploidy) is reported for the first time for the genus. Some correlations between ploidy levels and morphological characters are noted and several systematic and evolutionary aspects of the genus are discussed in the light of karyological data.

-In this study the effects of the herbicide linuron on somatic chromosomes of Helianthus annuus L were investigated. The roots were treated with 30, 120, 240 and 500 ppm concentration of linuron for 3, 6 and 12 hours. The mitotic and phase indexes were determined and chromosomal abnormalities were investigated in both control and test groups. It was found that linuron had a marked mitodepressive action on mitosis. The types of chromosomal abnormalities observed included: fragments, disturbed metaphase, c-mitosis, lagging chromosome, and chromatid bridge. A pronounced toxic effect is observed in concentrations 120 ppm and above its. It is considered that linuron may have genotoxic effects in higher plants.

The cytogenetic effects of the wastes of copper mine were investigated using root tip cells of Allium cepa L. The roots were treated with 10, 75 and 100 percent of copper wastes at 36 hour. Copper wastes caused some chromosomal abnormalities in root tip cells. It was found that copper wastes have a marked mitodepressive action on mitosis.

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