After staining pieces of fungal gills with ferroacetocarmine, it is possible to treat them in order to obtain sections of suitable thickness for electron microscopy. This allows to show eventually evidence for carminophilous granulations that should be doubtfull or even unnoticed with light microscopy. Using this cytological character, it is possible to determine more accurately the taxonomic position of certain fungi.
Cytological studies were conducted on two important cultivars of apple with a view to include in future breeding programme. The chromosome behaviour is normal, resulting in well filled pollen grains in the Ambritype. Accessory chromosomes with members of the normal 17 chromosome complement were noted in the variety Kulu Kenya. This appears to be the first report of its kind in temperate fruit trees. Morphologically there exists no distinction between the individual possessing the accessory chromosomes and the trees without them.
Experimental polyploids in Trichosanthes anguina have been raised. The tetraploid did not show superiority in its fruit size the character for which most of the cucurbits are grown probably on account of selection. Cytologically frequency of multivalent formation has not been found related to chromosome length. Attendant anaphase I irregularities are more accounted due to univalent formation. These studies have indicated that experimental polyploids from breeding point of view has not much future in cucurbits.
The effects of o-isopropyl-N-phenyl-carbamate (IPC) and “Duphar” were studied on root-mitosis of Vicia faba and Gossypium barbadense. Two types of treatments were conducted: seed-soak-, and root-treatments. Both agents effected a clear decrease in the mitotic index of Vicia faba after both seed-soak- and root-treatments. Treatment of Vicia faba roots with a saturated solution of “Duphar” proved to be the most effective treatment, the percentage of abnormal mitoses was much higher than that induced in the case of cotton roots. Roots treated with IPC recovered more rapidly than those treated with “Duphar”. Disturbed prophases, meta- and anaphases comprised the main type of the induced abnormalities. Lagging chromosomes, multipolar anaphases, chromosome stickiness, anaphase-bridges, chromosome fragmentation, and multinucleated cells were also observed.
The method of the preparation of the metaphase plates of the chromosomes of C. sativus L. is presented in this paper. The expressed specifity in the pattern of description of dense and stretched regions of chromosomes gives the possibility to identify all the chromosomes of this species.
Cytology and embryology of two forms of Tragopogon gracile was studied. Meiosis is normal, rarely chromatin bridges and precocious separation of one of the bivalents have been observed. Karyotypic studies revealed minor differnces between the forms. Anther wall development is of Dicotyledonous type. Microspore tetrads are formed by successive cytokinesis. Pollen grains are 2-celled at shedding. The embryo sac is of Polygonum type. Two to three per cent of capitula showed abnormal female gametophyte. Endosperm is ab initio cellular and embryogeny confirms to Asterad type. The T. gracile complex in Kashmir comprises at least two taxa (forms) and the dwarf named as T. gracile f. nanella nova.
Heterochromatic material in Reseda arabica appears in the interphase as densily stained masses (9-14). During meiotic prophase they are resolved as a string of large chromomeres. They pair homologously during the pachytene stage. Their behaviour during meiosis, indicate that they are of the autosomal type. Non homologous heterochromatin of different chromosomes fuse together at pachytene to form a giant mass of chromocentre similar in appearance to that found in the salivary gland chromosomes. The presence of this mass in such a way indicates that the heterochromatic material is mostly located around the centromere. In one chromosome, the heterochromatin appears as knobs near its distal end. The genetic value of the heterochromatin is discussed.
This paper estimates the radiation potentialities of high magnetic field on mitotic chromosomes of pea. A comparison is also made with the aberrations caused by urea and X-rays and their recovery in 1% sucrose. Mitotic indices are estimated by a new formula based on three dimensional graph with the assumption that every cell population constitutes of metaphase-anaphase ratio, the variance and the range of recovery.
Cytological investigations in 50 taxa belonging to 44 species and 21 genera of the tribe Andropogoneae have been carried out from the hills of Darjeeling and Nainital. Two genera, namely Apocopis and Ischnochloa and 13 species have been worked out for the first time. New counts are reported in six species. Comparative morphology of five cytological races has been undertaken. For the genus Sclerostachya, 5 is suggested to be the original base number and not 6 or 12 as suggested by Darlington and Wylie (1955) and Janaki-Ammal (1940). The base number x=5 is supported for the entire tribe Andropogoneae.
Cytological investigations of 46 taxa belonging to 35 species and 13 genera of the tribe Paniceae (Gramineae ) have been carried out from the hills of Darjeeling and Nainital. Of these 2 species, Panicum khasianum (n=18) and Setaria forbesiana (n=18) have been worked out for the first time. New chromosome numbers are made available for another 10 species, Digitaria ciliaris (n=9), D. cruciata (n=36), D. ternata (n=18), D. violascens (n=9), Oplismenus burmanii (n=18), O. compositus (n=27, 27+6-13B), Paspalum scrobiculatum (n=40), Pennisetum orientale (2n=45), P. triflorum (n=9) and Setaria paniculifera (n=27). Cytological races have been investigated for Barchiaria ramosa n=16, 18; Digitaria ciliaris n=9, 27; D. cruciata n=18, 36; D. violascens n=9, 18; Oplismenus compositus n=27, 27+6-13B and Pennisetum orientale n=9, 2n=45. The base number x=9 is suggested for the tribe Paniceae.
Mecardonia dianthera, a Scrophulariaceous weed of Tropical America comprises of two edaphic ecotypes viz. erect and repent. While the former is a facultative calcicole, the latter is an obligate calcifuge. The present paper gives an account of plant performance and cytological behaviour of colchicine induced tetraploids that were produced by treating the inbred lines of these plants with 0.3% colchicine for 12 hours. Majority of the surviving plants were tetraploids exhibiting a slower growth delayed phenological events, deep green thick green rough foliage, increased dry matter production, enlarged epidermal and mesophyll cells, chloroplast, stomatal apparatus and frequency, pollen grains and a reduced seed viability than that of the diploids. While repent ecotype tetraploids had increased flower number per plant than that of the diploids, reverse was observed in the erect ecotype tetraploids. At metaphase I, uni, bi, tri, tetra and hexa-valents in a varying frequency were observed in the colchiploids and the total number of multivalent associations and univalents per PMC on an average was equal in the tetraploids of each ecotype. This indicates a competition for pairing between homologous chromosomes which is supported by the fact that a significant positive correlation between chiasma frequency and multivalent formation was also observed. However, the colchiploids of the erect ecotype possessed greater number of multivalents and univalents than those of the repent ecotype colchiploids. Further stages of meiosis in the colchi-ploids were abnormal and resembled the typical autoploid meiois. Multiple spindles, complement fractionation and secondary association were also observed. The contribution of univalents and multivalents in inducing pollen sterility in the tetraploid material is significant. Attempts to cross these colchiploids with diploids produced non-viable abortive seeds. Artificial crossings amongst these colchiploids resulted in an early degeneration of the ovary and a failure of the seed formation. Natural self pollination yielded 5-9% of seeds that died after an extrusion of radicle when germinated. The study indicated that the two edaphic ecological races (ecotypes) exhibit a differential susceptibility to colchicine in relation to frequency of induced polyploids, morphological and reproductive features, number and frequrncy of chromosomal associations and univalents, pollen and seed fertility. However, a general agreement in having a morphological gigas, slowed growth rate, delayed phenological events and reduced reproductive capacity occurs in the tetraploids in comparison to the diploid progenitors, of both the ecotypes. A tendency to change the plant form (repent erect), which is governed by a single gene, was not observed, indicating thereby that the gene remains uneffected by the drug, in both the ecological races of M. dianthera.
Structures containing polysaccharide in cells of Micrasterias americana were studied cytochemically with silver-hexamine solution. Polysaccharides, such as starch, cell wall and slime, produced electron dense precipitates with silver-hexamine. Three different types of vesicles also produced precipitates on treatment with the solution, and so seemed to contain polysaccharide. Large vesicles shaped like a fibril-ball appeared to release their fibrous inclusions into spaces between the plasma membrane and the cell wall. The two other types of vesicles, one very electron dense and the other moderately dense, seemed to migrate from the cytoplasm through the plasma membrane to the cell wall, and to contribute to development of the cell wall.
The chromosome complement and the incidence of polyploidy, sex chromatin and chromosome aberrations were analysed in primary kidney and lung cells from the rabbit (Oryctolagus cuniculus) and in two continuous cell lines (E4L1 and E4L2) initiated from embryonic lung tissue. Chromosome polymorphism in the short arm of pair 11, probably produced by chromosome contraction because of colcemid treatment, was found in primary and cultured cells. Primary cultures showed 0-25% aneuploid metaphases and 0-4% chromosome aberrations. Polyploidy ranged from 6-14% in epithelial-like primary cultures and 1-3% in fibroblast-like primary cultures. Sex chromatin in female cells ranged between 5-42% depending on whether the studies were performed on non-confluent cultures (lowest percentage) or confluent cultures (highest percentage). Chromosomal analysis on passage 10, 29, and 34 of the E4L1 line showed a progressive increase in the polyploid index (2% in passage 10, 15% in passage 34); the percentage of cells with normal karyotype varied from 85-90%. Two different series of cultures of the line E4L2 behaved similarly: they were diploid up to passage 20 and suddenly became hyperdiploid between passages 21-25. A comparison of the karyology of primary and cultured cells allowed one to suggest that the definition of diploidy for cultured cells should be based on: a) karyological analysis of successive cell samples of the same line separated by approximately 10 passages, b) comparison of the karyology of cultured cells with the karyology of primary cultures from which the line was initiated.
The structure of the nucleolus associated chromatin in avian neurons is described. It consists of one or two great heterochromatic blocks applied side by side to the nucleolus. Included within the nucleolar mass there are chromatinic filaments originated from the heterochromatic blocks. Analysis of autoradiographical preparations reveals that the nucleolus associated chromatin incorporates 3H uridine and 3H thymidine at a high rate. It is hypothetically postulated for this cellular type, that the process of formation and accumulation of the nucleolar substance in the middle zone between the heterochromatic blocks could be comparable to the formation of “puffs” in dipteran polythene chromosomes.
A white male infant was born at 40 week's gestation with multiple malformations and one eye missing. At two weeks of age, he developed a mixed urinary tract infection. At four weeks of age, bilateral peribronchiolar pneumonia developed. The course was marked by vomiting and progressive diarrhea, leading to death at six weeks (42 days) of age. Postmortem examination revealed the absence of the left optic nerve and eyeball with shallow left orbit, among other abnormalities. Sex chromatin was negative. All 37 metaphases analysed on leucocyte cultures contain 45 normal chromosomes plus a typical ring chromosome, which is present in place of one of the E group chromosomes, either no. 17 or no. 18. Judging morphologically, the ring chromosome probably arose from a chromosome no. 18.
The megasporogenesis and the female gametophyte development in the ovule of Dipcadi montanum Dalz. were studied using the cytochemical staining techniques for polysaccharides, DNA, RNA and proteins. The insoluble polysaccharides are at very low level in the archesporium, MMC, dyads, tetrads and functional megaspore stages while RNA and proteins are at a higher level of concentration in all of them. The degenerating spores have an intense concentration of RNA and proteins in them. The cytoplasm of young embryo sac and the central cell of mature embryo sac has a low concentration of polysaccharides, RNA and proteins. The enlarged, haploid nuclei in the dyad cells, tetrad of spores, functional spore and young embryo sac have very faint DNA stainability. In the mature embryo sac, the egg cell has a low concentration of cytoplasmic polysaccharides and RNA while proteins are at a very high level; the synergids have densely PAS positive filiform apparatus and rich concentration of cytoplasmic proteins while they have very less RNA content; the antipodal cells have enlarged nuclei with rich DNA staining and their cytoplasm has rich polysaccharides and proteins. The enlarged fusion nucleus or the free polar nuclei have less DNA in them. The cells of the hypostase and those of the integuments at the growing tips have rich RNA and proteins.
The chromosome number in the antheridial filament cells of Nitella axillaris was investigated and found to be 36, although some cells of the same antheridium had more or less than this number. A comparison was made between the chromosome number of Nitella axillaris and other Characeae plants, and the possible origin of the chromosome number 36 was suggested. Amitotic nuclear division by a process of gradual pulling apart of the nucleus into two parts was observed in the lateral, internodal and rhizoidal cells.
As a part of the programme of induction of polyploidy in various species of Amaranthaceae, two species viz. Amaranthus hypochondriacus L., a natural dipoid with haploid chromosome number of n=16 and A. dubius Mart. ex Thell., a natural tetraploid with n=32 were selected for the present study with a view to have compara-tive picture of induced polyploidy at tetraploid and octoploid levels. Various types of morphological changes were noted in colchicine treated plants. Meiotic analysis revealed varied proportions of hexavalents, quadrivalents, bivalents and univalents in the polyploid cells with other cytological abnormalities such as the uneven separation of the chromosomes and the laggards. These result in the organi-sation of the micronuclei and polysporic condition which may account for high degree of pollen and seed sterility. Comparatively percentage of induction of polyploidy in A. dubius is found to be less than that of A. hypochondriacus. On the other hand frequency and grade of multivalent association is rather higher in A. dubius than those of A. hypochondriacus. The meiotic irregularities in the induced polyploids of A. dubius are also greater than those of A. hypochondriacus which may account for greater percentage of sterility in this induced octoploid.
The detailed analysis of the Clintonia udensis chromosome complement demonstrated the 2 n=28 karyotype to be remarkably consistent, with no aneusomaty. Root tip chromosomal lengths under both colchicine and 8-hydroxyquinoline pretreatments were virtually identical. The karyotype may be roughly symbolized as: K(2n)=28=4V+12J+4v+8j(2NOR+6j).
Karyotypes and meiosis in 13 species of the genus Fimbristylis have been studied. Karyotypes in F. acuminata (2n=10), F. barbata (2n=10), F. bisumbellata (2n=10), F. cinnamometorum (2n=10), F. complanata (2n=10), F. argentea (2n=20) and F. spathacea (2n=48) have been studied for the first time. The most widely represented basic number is x=5. Cytological data suggest the primitive status of this genus in Cyperaceae. Both structural changes and polyploidy seem to have played a major role in the evolution and speciation in Fimbristylis.
Chromosome number, meiotic behavior, pollen stainability and other morphologic and ecologic data from 35 strains belonging to 29 natural and cultivated entities of the genus Axonopus collected in Rio Grande do Sul, other Brazilian States and Uruguay are reported. In the series Axonopus n varied from 10 to 50 (2x-10x); the series Suffulti shows diploid and tetraploid entities, while in Barbigeri only diploids were observed. In a general way our results agree with those obtained by other authors in those taxa where previous cytological studies were made; some ploidy levels observed in A. compressus and A. affinis, however, were not encountered by us. Meiotic abnormalities were most frequent in the Suffulti series, occurring in six of the seven tetraploid entities studied; in the Axonopus series about half of the polyploid forms had a regular meiotic behavior, while the five Barbigeri strains studied showed an essentially regular pattern. Subspecific hybridization may be involved in the origin of the taxa of the first series, while in the second allopolyploidy may have played an important role. Peculiar non-chromosomic structures were observed in the pollen mother cells of two strains of the series Suffulti, resembling the round and nuclear bodies described previously in Zea and Bromus.
The use of janus black, janus blue and janus red as aqueous solutions in the staining of acid hydrolysed tissue sections is recommended. Janus black-SO2, when prepared with N HCl and potassium metabisulphite and used in the staining of acid hydrolysed DNA reveal well stained nuclei at pHs 2.0, 3.0 and 4.0. Sections stained with janus blue-SO2 show optimum staining at pHs 3.0 and 4.0. Janus red-SO2 prepared by this method reveal very pale staining of the nuclei. Janus black and janus blue when prepared with sodium hydrosulphite and used in the staining of DNA following the Feulgen procedure reveal nuclei which are of magenta colour. Janus black, charged with sodium hydrosulphite, becomes metachromatic in staining nuclei with a magenta colour and blue mucus glands as studied with rat rectum. Unhydrolysed sections stained with these dyes also show well stained nuclei and the cytoplasm and alkali hydrolysed sections stained with them show only nuclei. These phenomena indicate that staining of both DNAP and RNAP and also DNAP alone is possible with these dyes. Staining with janus red without any primary anino group in its molecule has been considered as modified Feulgen reaction and that with janus black and janus blue with primary amino group in their molecules as due to Feulgen type of reaction. The absorption characteristics of these dye solutions as well as those of nuclei stained with these dyes are presented in this paper.
Rose cultivar ‘Montezuma’ and two of its gamma ray induced mutants presented a marked distinction in their cytological features. Their male meiosis revealed a great variation with regard to chromosome associations at metaphase I which comprised of univalents, bivalents, trivalents and quadrivalents. Ring shaped quadrivalents were more common than the chains. The frequency of quadrivalents was enhanced in mutant plants. The percentage of PMCs with precocious separation, laggards and bridges at anaphases was found to be higher in mutants as compared with the control plants. These results indicate that chromosomal structural changes might also be responsible for the induction of these mutations. The pollen fertility decreased in Pink flowered mutant as compared with control, whereas, an increase was recorded in Reddish-orange flowered mutant. The nature of above mentioned variations in gamma induced mutants may be chromosomal/genic or both.