Molecular cytogenetic analysis in seven species of Lachenalia (Liliaceae) with 2n=18, 22, 23, 26 and 28 was studied using DAPI staining and fluorescence in situ hybridization (FISH). Lachenalia latimerae (2n=18), L. juncifolia (2n=22) and L. zeyheri (2n=23) would be considered as diploids which had basic chromosome numbers of x=9, 11 and 11, respectively. They showed similarities in the characters of DAPI bands and FISH signals of 5S rDNA and 18S rDNA sites. Lachenalia aloides var. vanzyliae (2n=28) and L. orchioides (2n=28) showed tetraploidy (X=7). Lachenalia paucifolia (2n=26) and L. longituba (2n=28), which belonged to the genus Polyxena by different system, considered as diploids which might have in respect to their basic chromosome numbers of x=13 and 14. Lachenalia paucifolia and L. longituba showed different characters of DAPI bands and FISH signals of 5S rDNA and 18S rDNA and showed different characters from the other species of Lachenalia studied here.

View full abstract

Presently, meiotic studies have been carried out on five accessions of Clematis grata collected from different areas of Western Himalayas as localities selected in Himachal Pradesh, Kashmir and Uttarakhand. The cytomixis is observed from early prophase-I upto tetrad stage of meiosis. The percentage of PMC's (pollen mother cells) involved in chromatin transfer is quite high and may involve group of PMC's. PMC's with hypo- and hyper-ploid chromosome numbers are also observed. Cytomixis and other meiotic abnormalities are reported for the first time in this species and seem to be directly under genetic control. The meiotic abnormalities include the presence of unoriented bivalents at metaphase I, laggards and chromatin bridges at anaphases and telophases. The frequency of chromatin stickiness is seen to be very high. Microsporogensis is abnormal with the formation of micronuclei and production of heterogenous sized fertile pollen grains with reduced pollen fertility. The occurrence of B-chromosomes in some of the PMC's in one of the accessions makes its first report for the species.

View full abstract

Cytogenetical and ecological studies in some species of the Solanaceae were made in the Mediterranean-type ecosystem in Upper Egypt. The chromosome complement of Datura innoxia (2n=24) consisted of 24 median-centromeric chromosomes; that of D. stramonium (2n=24) consisted of 22 median- and two submedian-centromeric chromosomes; that of Hyoscyamus albus (2n=68) consisted of 62 median- and six submedian-centromeric chromosomes, that of H. muticus (2n=28) consisted of 21 median- and seven submedian-centromeric chromosomes; that of Withania somnifera (2n=36; new count) consisted of 27 median- and nine submedian-centromeric chromosomes; and that of Solanum nigrum (2n=72) consists of 68 median and four submedian-centromeric chromosomes. Thirty-three reproducible polymorphic bands were resulted after four RAPD-PCR primers; those bands were used for studying the genetics similarity among the species. Average similarity coefficient was ranged from 0.05 to 0.47. RAPD bands resulted after PCR: D. innoxia and D. stramonium showed five bands each; H. albus and H. muticus showed two and one bands respectively; W. somnifera seven bands and S. nigrum showed 13 bands, different patterns were produced among congeneric species. Ionic status of hot water extract of the species revealed that Hyoscyamus species was more accumulated Na⁺ and Ca⁺⁺, while Datura species accumulated more K⁺ and Mg⁺⁺ and W. somnifera and S nigrum were intermediate. These strategies of ionic accumulation were in relation to the different chromosome number of species, which might help for surviving the species in desert ecosystem.

View full abstract

Chromosomes at prophase and metaphase in five individual plants of Spiranthes amoena (M. Bieb.) Spreng collected in a little wet area in Buryat Republic: near Solzan River, 8 km up along the left side of the River from the bridge of the Irkutsk were studied. The chromosome numbers of the plants studied were commonly counted as 2n=60, doubled number of chromosomes of S. sinensis. The karyotype at prophase was 2n=60=40h+16he+4e followed Tanaka's system (1969) suggested that those plants should be treated simply the autotetraploid form of S. sinensis. Thus, plants of S. amoena grown in Buryat Republic could be called as S. sinensis var. amoena (M. Bieb.) Hara.

View full abstract

The chromosome number of Camellia changii Ye, a summer flowering camellia, was 2n=30, diploid (X=15), reported here for the first time.

View full abstract