Karyotype studies were performed in 18 populations of eight Helichrysum species in Iran. Those species showed chromosome numbers of 2n = 2x = 14; 2n = 4x = 24, 28 and 32; 2n = 6x = 36; 2n = 7x = 42; 2n = 8x = 48; 2n = 9x = 54; and 2n = 10x = 60. The chromosome numbers of H. davisianum, H. globiferum, H. leucocephalum and H. oocephalum are reported here for the first time. New ploidy levels are reported for H. oligocephalum (2n = 4x = 24) and H. plicatum (2n = 4x = 32). The chromosomes were metacentric and submetacentric. An ANOVA among H. globiferum and H. leucocephalum populations showed significant differences for the coefficient of variation for chromosome size, total form percentage and the asymmetry indices, indicating that changes in the chromosome structure of Helichrysum species occurred during their diversification. Significant positive correlations among the species and populations studied, in terms of the total chromosome length, lengths of the short arms and lengths of the long arms, indicate that these karyotypic features change simultaneously during speciation events. The genome sizes of Helichrysum species are reported here for first time. The 2C DNA content ranged from 8.13 pg (in H. rubicundum) to 18.4 pg (in H. leucocephalum and H. davisianum). We found that C-value correlated significantly with ploidy level, total chromosome length, lengths of the long arms and lengths of the short arms (p<0.05), indicating that changes in chromosome structure are accompanied by changes in DNA content.

The genus Centaurea L. is one of the largest genera in the family Asteraceae. The number of taxa included in this genus ranges from 500 to 600 worldwide. Iran is one of the major centers of diversity for this genus. Pollen morphology has proved useful in the systematics of Asteraceae, as well as in that of some of its genera and species. The pollen morphology of 19 taxa of the genus Centaurea was investigated in detail by light and scanning electron microscopy. Examination under light microscopy showed pollen grains to be tricolporate, isopolar, radially symmetrical, oblate spheroidal, prolate spheroidal, subprolate, tectum perforate and scabrate. Based on the exine ornamentation observed under scanning electron microscopy, we identified two types of pollen grains, designated type I (dense acute spinules) and type II (sparse spinules). All of the taxa evaluated resemble Wagenitz's Jacea type. We present micrographs of pollen grains, together with descriptions of the characteristics of their structure. We found that the pollen characters (shape, exine structure, sculpturing) were useful for classification.

A romã (Punica granatum L.) é uma planta hortícola importante com diversas formas de cultura plantadas em diferentes regiões do Irã. Devido à sua importância econômica, alguns estudos genéticos têm sido realizados para ilustrar a diversidade genética em ambos os níveis cromossômico e molecular em diferentes cultivares de romã que crescem neste país. O presente estudo considera as análises de pareamento cromossômico e cromossomo-B em 21 cultivares de romã e tenta investigar os efeitos dos parâmetros geográficos, como altitude e longitude, bem como a elevação e a queda de chuva média anual sobre a diversidade citogenética destes cultivares. O teste ANOVA revelou a presença de uma diferença significativa para quiasmas e emparelhamento de cromossomos entre as cultivares, indicando a sua diversidade genética. A correlação positiva e significativa foi observada entre o freqüência total de quiamas de quiasmas terminais, quiasmas intercalares e o número médio de quadrivalentes. Uma correlação positiva foi observada entre a queda da chuva anual e o número médio de bivalentes haste, com correlação negativa significativa com o número de bivalentes anel. A altitude não mostrou qualquer correlação com caracteres citogenéticos estudados, enquanto a altitude apresentou correlação negativa significativa com o número de monovalentes. A longitude mostrou correlação positiva e significativa com o número de bivalentes anel e correlação negativa com o número de univalentes e chismata intercalares. A análise de PCA mostrou que tanto as características geográficas quanto citológicos podem contribuir grandemente na diversidade observada nas cultivares de romã. A ocorrência de células multipolares e grãos de pólen não reduzidos foram observados em alguns dos cultivares.

Pomegranate (Punica granatum L.) is an important horticultural plant with several cultivated forms planted in different regions of Iran. Due to its economic importance, studies have been carried out to illustrate the genetic diversity at the chromosomal and molecular levels in different pomegranate cultivars growing in this region. This study analyzed chromosome pairing and B-chromosomes of 21 pomegranate cultivars and tried to investigate the effects of geographical parameters like altitude and longitude as well as elevation and the mean annual rainfall on cytogenetic diversity of these taxa. An ANOVA test revealed the presence of a significant difference for chiasmata and chromosome pairing among the cultivars, indicating their genetic differences. A positive significant correlation was observed between total chiasma frequency and terminal chiasmata, intercalary chiasmata and the mean number of quadrivalents. A significant positive correlation was observed between annual rainfall and the mean number of rod bivalents, while a significant negative correlation was found for the number of ring bivalents. Altitude did not show any correlation with the cytogenetic characters studied, but showed a significant negative correlation with the number of univalents. Longitude showed significant positive correlation with the number of ring bivalents and a negative correlation with the number of univalents and intercalary chiasmata. PCA analysis showed that both geographical and cytological features contribute greatly in the diversity observed in the pomegranate cultivars. The occurrence of multipolar cells and unreduced pollen grains were observed in some of the cultivars.

Meiotic studies of ploidy level, chromosome paring and chiasma frequency were performed on 11 Cousinia (Asteraceae) species of the section Serratuloideae. The diploid number of the species studied was 2n = 2x = 24 and 26 so these species possess two different basic numbers (x = 12 or 13), a phenomenon common to other sections of the genus. The chromosome numbers of 9 species are reported here for the first time. When the 2n = 24 and 2n = 26 species were subjected to cluster analysis based on relative meiotic characters two different clusters were formed indicating their distinctness. Our data support the results obtained from morphometry, anatomy, pollen morphology and molecular studies of the genus Cousinia.