Based on the cytological and molecular studies, types and frequency of chromosomal aberrations during meiotic division of wheat plants treated with different concentrations of deoxynivalenol (DON) were investigated. The common types of abnormalities that have been recorded were stickiness, outside, laggards, bridges, fragments, unequal division, as well as multipolar and micro- nucleated cells. Regarding the first meiotic division, the percentage of abnormal cells detected from untreated plants was 2.12% however, plants treated with 5, 10, 15, 20 and 25μg/ml DON revealed 3.73, 6.62, 6.78, 9.23 and 8.18% of abnormalities, respectively. In the second meiotic division, control plants exhibit 2.69% of abnormalities while, 2.29, 4.34, 4.23, 5.59, 4.46% of abnormal cells were detected from plants treated with 5, 10, 15, 20 and 25μg/ml DON, respectively. These results demonstrate the significant effect of treatment with DON on the total percentage of irregularities during meiosis. DNA amplification patterns of wheat plants treated with DON using two RAPD primers revealed some variations in the DNA profiles within the examined samples as compared with the control. Such variations include band intensity and appearance of novel bands or disappearance of others. The polymorphism of the detected DNA fragments particularly the absence of a number of fragments in some plants treated with different concentrations of DON suggested that contaminated wheat grains with this toxin or mycotoxigenic fungi might induce DNA rearrangements, deletions and/or changes in the DNA sequence that lead to the observed changes.

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Chromosome numbers and karyotypes are presented in eight taxa in Chrysanhemum senu lato (Asteraceae). Achillea santolina, Cotula barbata and Co. cinerea had new counts for the first time. The chromosome complement of Artemisia arborescens (2n=18) consists of 14 median and four sub- median chromosomes. Achillea fragrantissima (2n=18) consists of 14 median and four sub- median chromosomes; Ach. santolina (2n=36) consists of 26 median- and ten submedian-centromeric chromosomes. Glebionis coronaria (2n=18) consists of 18 median-centromeric chromosomes; while G. coronaria var. discolor (2n= 18) has 16 median- and two submedian-centromeric chromosomes. Cotula barbata (2n=16) consists of 12 median- and four sub-median-centromeric chromosomes, while Co. cinerea (2n=18) has 14 median- and four sub-median-centromeric chromosomes. The chromosome complement of Matricaria recutita (2n=18) consists of 14 median-, two submedian- and two subterminal-centromeric chromosomes.The longest chromosome complement was Artemisia arborescens while the shortest was Cotula barbata. The length of the tetraploid chromosome complement of Ach. santolina was approximately one third shoter than the diploid Artemisia arborescens, and equal to G. coronaria.

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Cytological studies on two species of saprophytic orchids were carried out. Neottia asiatica showed the resting chromosomes of the complex chromocenter type and the mitotic prophase chromosomes of early condensed segments located in their distal and interstitial regions. The species had the chromosome number of 2n=50 that was different from the previous count of 2n=36 by Sokolovskaya (1966). The chromosome complement at mitotic metaphase showed a gradual decrease in chromosome length from 5.1-1.4 μm. In contrast, Epipogium japonicum showed the resting chromosomes of the diffuse type and the mitotic prophase chromosomes of early condensed segments located in their proximal regions. The species had the chromosome number of 2n=78, counted here for the first time. The chromosome complement at mitotic metaphase showed a gradual decrease in chromosome length from 2.0-1.1 μm.

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Chromosome numbers in 140 accessions of 37 annual and perennial species of Trifolium L. in Iran were counted and studied here. The chromosome number of 2n=16 was documented in Trifolium radicasum in Iran. New cytotypes were found in Trifolium ambigum, T. fragiferum, T. montanum, T. nigrescens, T. stellatum and T. tumens. This study deposited more data in chromosome numbers of Trifolium to determine the genus has high diversity of ploid level. Their karotypic formula showed that the most of the chromosomes were median-, submedian- or terminal-centromeric. The smallest chromosomes were found in Sections Versicaria and Mistyllus, while the largest chromosomes were found in Sections Trifolium and Tricocephalum. Thus, Trifolium seemed to be heterogeneous with respect to morphological characters of chromosomes.

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