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Volume 44, Issue 2
Displaying 1-24 of 24 articles from this issue
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R. Sampathkumar1979 Volume 44 Issue 2 Pages 275-286
Published: June 25, 1979
Released on J-STAGE: March 19, 2009
JOURNAL FREE ACCESSKaryomorphological details pertaining to chromosome measurements in 27 taxa of South Indian Convolvulaceae have been described. The systematic status of the different genera like Cuscuta, Rivea, Argyreia, Jacquemontia, Merremia, Operculina, Hewittia and Ipomoea have been discussed.View full abstractDownload PDF (614K) -
Gregg A. Johnson, S. M. Jalal1979 Volume 44 Issue 2 Pages 287-294
Published: June 25, 1979
Released on J-STAGE: March 19, 2009
JOURNAL FREE ACCESSPopulations of Agropyron and Agrohordeum species were sampled over a two year period at four native prairie sites of northcentral Minnesota and northeastern North Dakota along a 120 mile transect. One hundred and five plants from four species were collected and analyzed each year for two years, for physiological chromosome aberrations. Physiological disturbances ranged from prophase pycnosis, split and double metaphase plates, sticky bridges and adnations, globular structures, coenocytes and fragmentation of chromosomes. The levels of these aberrations were higher during earlier stages of microsporogenesis. With the exception of Agrohordeum macounii there was a significant negative correlation between physiological aberrations and fertility levels in Agropyron repens, A. dasystachyum and A. trachycaulum. It is conjectured that the primary cause for physiological aberration is the interaction between non-harmonious genomes which occur due to frequent hybridization in these polyploid species.View full abstractDownload PDF (1884K) -
M. Perez De La Vega, J. R. Lacadena1979 Volume 44 Issue 2 Pages 295-304
Published: June 25, 1979
Released on J-STAGE: March 19, 2009
JOURNAL FREE ACCESSAlloplasmic plants of rye, Secale cereale L., with cytoplasm of Triticum durum Desf. are studied in order to investigate the causes of male sterility. Meiosis can be considered as normal because the alterations found had little entity. Abortion of pollen was progressive during microspore maturation; however, the variation among plants in percentage of aborted pollen was high (from 10%. to 98%.), being the average 29.3%. Histological observations showed that the only alteration in anther wall tissues was the non total disappearance of tapetum. So, the fusion of neighbouring loculi and the subsequent dehiscence of the anther was impeded. Therefore, the male sterility in this alloplasmic rye is a case of functional male sterility because the pollen being partially fertile cannot intervene in fertilization by the indehiscence of the anthers. The independence between pollen abortion and tapetum perdurability is discussed. Other events as pistilloidy are described.
All studies were made simultaneously with the normal rye counterpart as control.View full abstractDownload PDF (1275K) -
M. S. Chennaveeraiah, Shanta R. Hiremath1979 Volume 44 Issue 2 Pages 305-314
Published: June 25, 1979
Released on J-STAGE: March 19, 2009
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F. B. Kulfinski1979 Volume 44 Issue 2 Pages 315-318
Published: June 25, 1979
Released on J-STAGE: March 19, 2009
JOURNAL FREE ACCESSFeulgen DNA of inner epidermal onion nuclei ranged from l× at the base of the onion bulb to 3.6× at the equator to 1.8× at the apex. This was compared to unpublished interference microscopy data which showed corresponding changes in nuclear area (cross section) from 1× to 2.7× to 2.0×, nuclear dry mass per unit area from 1× to 1.5× to 1.4×times;, and total nuclear dry mass from 1× to 4.2× to 2.8x from base to equator to apex, respectively. A regression of each of these three characteristics against relative DNA indicated that within the range of values given above, the interferometric characteristics reached maximum or stabilized as DNA reached high levels and continued to increase. This suggests first, that nuclei tend to increase in these characteristics during plant development and second, that these increases seem to be related to cell, organ, and plant size, age, and location.View full abstractDownload PDF (231K) -
Suhaileh Al-Allaf, M.B.E. Godward1979 Volume 44 Issue 2 Pages 319-323
Published: June 25, 1979
Released on J-STAGE: March 19, 2009
JOURNAL FREE ACCESSDownload PDF (1282K) -
V.B. Kulshreshtha, P.K. Gupta1979 Volume 44 Issue 2 Pages 325-334
Published: June 25, 1979
Released on J-STAGE: March 19, 2009
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R.L. White, D. Davidson1979 Volume 44 Issue 2 Pages 335-345
Published: June 25, 1979
Released on J-STAGE: March 19, 2009
JOURNAL FREE ACCESSDiploid microspores were induced in Tradescantia paludosa by heat shocks; they occurred in anthers that also contained normal haploid microspores. Nuclear and cell volumes were determined from early G1 to late G2 for diploid and haploid microspores present in the same anther. Although the two cell types showed considerable overlap in cell and nuclear volumes, values from mixed samples did not yield a single straight line on a probit plot; there were always two straight lines articulated by an inflection point. The probit plots were used to distinguish between haploid and diploid microspores. Evidence is presented that demonstrates the degree to which this method is reliable. The two cell types developed at similar rates; they entered S and mitosis together and the time, in interphase, when increases in cell and nuclear volumes occurred was approximately the same for haploid and diploid microspores. However, increases in nuclear and cell volume occur at different rates during interphase and it appears that there is a poor correlation between nuclear DNA content and either cell or nuclear volume.View full abstractDownload PDF (713K) -
Pulak Mukherjee1979 Volume 44 Issue 2 Pages 347-352
Published: June 25, 1979
Released on J-STAGE: March 19, 2009
JOURNAL FREE ACCESSThe karyomorphological studies of the ten different strains of R. sativus show homogeneity in their gross morphology. However, minute structural difference between different strains are noticed in relation to the number of secondary constriction, the position of the primary constrictions as well as in the arm ratio. However, in one of the strains, viz. “Deshi red long” the chromosome size has been found to be comparatively longer than the rest as noted from the histogram as well. It is likely that this strain is the representative of the primitive stage and that other strains with shorter chromosomes are evolved through horticultural practices. In that case the diminution in chromosome size is assumed to have taken place during evolution. It has been suggested that the structural changes in chromosome have played an important role in the evolution of different taxonomic units of Raphanus sativus L.View full abstractDownload PDF (819K) -
D. Oliveira, C. Semino, A.J. Soiari, N.O. Bianchi1979 Volume 44 Issue 2 Pages 353-357
Published: June 25, 1979
Released on J-STAGE: March 19, 2009
JOURNAL FREE ACCESSThree-dimensional reconstructions of the XY chromosomal pair in spermatocytes of Akodon azarae show that the ultrastructural axes of the X and Y chromosomes pair partially to form a long synaptonemal complex. The differential (unpaired) region of the X axis shows an unusually long and permanent splitting into two elements, which form an anomalous synaptonemal complex. The chromatin of the XY body is less closely packed than the autosomal chromatin during all synaptic stages. The length ratio of the X and Y axes differs from the length ratio recorded for normal, somatic X and Y chromosomes.View full abstractDownload PDF (1425K) -
S.K. Bhadra, M.A.Q. Shaikh, M.M. Mia1979 Volume 44 Issue 2 Pages 359-364
Published: June 25, 1979
Released on J-STAGE: March 19, 2009
JOURNAL FREE ACCESSThe purpose of the present study was to detect and explain the various types of chromosomal abnormalities resulting from seed irradiation and to evaluate the frequency of abnormal cells in different doses and thereby establish the relative radiosensitivity between the 2x (2n=14) and c-4x (2n=28) (colchicine-induced) Corchorus capsularis.
Air-dried seeds of the two ploidy levels were exposed to 60, 70 and 80 KR gamma-rays (60Co) and different stages of the mitotic division of the treated and control root tips were studied. There was no chromosomal abnormality in the untreated root-tip cells of both the types. The aberrations in the irradiated samples included: a) only bridges, b) only laggards and c) both bridges and laggards in the anaphase of root-tip cells of both the ploidy levels, d) much more variation in length of metaphase chromosomes in c-4x capsularis. Plausible causes of the origin and occurrence of the abnormalities have been discussed in the light of the findings of other workers in the field.
There was increase in the frequency of abnormal cells with the increase in radiation dose in both the ploidy levels but at a given dose c-4x capsularis produced more aberrations than the 2x diploid. It was concluded that the artificially induced autotetraploid was more radio-sensitive than the 2x type. This perhaps, was due to the artificial nature of origin of the autotetraploid and its lack of sufficient adaptation to protect itself from radiation effect.View full abstractDownload PDF (820K) -
S.N. Raina, R.C. Verma1979 Volume 44 Issue 2 Pages 365-375
Published: June 25, 1979
Released on J-STAGE: March 19, 2009
JOURNAL FREE ACCESSDetailed karyotype studies have been undertaken in 20 species. Some of them have been investigated for the first time. Nineteen species have the mitotic complement of 16 chromosomes, while in C. incana it is 14. There is no clearcut size differences among the chromosomes. The somatic complement in various species is characterized by overall uniformity in karyomorphology. In as many as ten species the somatic complement resolved into 14L+2V. It is concluded that species differentiation in the genus cannot be correlated with chromosomal differentiation. Three broad categories of nucleolar chromosomes have been recognized in nine species. The number of nucleolar chromosomes is always two. Karyotypic heterozygosity has been found in only three species, which may be accompanied by the heterozygosity in nucleolar chromosomes as in C. laburnifolia. The speciation and evolution in the genus Crotalaria appears to be mostly due to structural changes, Polyploidy has not played any significant role in speciation of the genus. There is an overwhelming evidence that the true basic number of the genus is eight.View full abstractDownload PDF (1613K) -
P. Sreedevi, A.N. Namboodiri1979 Volume 44 Issue 2 Pages 377-384
Published: June 25, 1979
Released on J-STAGE: March 19, 2009
JOURNAL FREE ACCESSThe chromosome number of Asclepias curassavica and Dregea volubilis is confirmed as n=11 and 2n=22. Normal microsporogensis in both genera is characterized by the following atypical features: marked variations in the size and shape of the pollen mother cells and pollen grains, the segmentation of the nucleolus in the leptotene-zygotene stage and the presence of germinating exineless pollen protoplasts with normal tube growth.
Both plants exhibit seasonal sterility during summer. Microsporogenetic aberrations leading to pollen inviability occur at a temperature range of 30°-35°C in contrast to the previously reported induction of aberrations at 37°±1°C. Various chromosomal aberrations associated with high temperatures such as presence of univalents, chromosome associations, unequal anaphase separation as well as unlisted heat associated cytokinetic abnormalities involving incomplete cytoplasmic cleavage and irregular segmentation result in the production of spores with wide variation of size and chromatinic contents. Consequently, pollen grains produced by these plants during summer are almost totally sterile. However, with the fall in temperature below 30°C, plants revert to normal microsporogenesis and pollen viability is restored.View full abstractDownload PDF (1500K) -
R. O. Giacomozzi, Rita Riva, O. R. Vidal1979 Volume 44 Issue 2 Pages 385-389
Published: June 25, 1979
Released on J-STAGE: March 19, 2009
JOURNAL FREE ACCESSThe study of mitotic and meiotic chromosomes of the fresh water snail Biomphalaria tenagophila is reported. Three populations, two from Argentina (Buenos Aires and San Miguel de Tucumán) and one from Uruguay (Carrasco), were investigated. The haploid number of the species is n=18 and the diploid number is 2n=36. The fundamental number is FN=68.
The karyotype is composed of 8 pairs of metacentric, 8 pairs of submetacentric and 2 pairs of acrocentric chromosomes. Secondary constrictions were apparent in the first pair of the Carrasco's population.View full abstractDownload PDF (584K) -
P. N. Ravindran1979 Volume 44 Issue 2 Pages 391-396
Published: June 25, 1979
Released on J-STAGE: March 19, 2009
JOURNAL FREE ACCESSVanilla pollen was cultured on a nutritive medium and germination count after five hours was found to be 45%. In about 12% of the pollen grains a nuclear division was present. This division was similar to the first pollen mitosis. Various abnormalities in chromosome behaviour was recorded. The percentage abnormalities varied from 17.0 to 38.2 in different flowers. Similar nuclear divisions and chromosome abnormalities were also found in flower buds collected at 24, 48, and 72 hours prior to anthesis. This unusual behaviour might either be the result of delayed first pollen mitosis which should have taken place soon after the organisation of pollen grains or they represented a premature division of the generative nucleus.View full abstractDownload PDF (865K) -
R. N. P. Shahi, A. P. Mishra, B. R. Singh1979 Volume 44 Issue 2 Pages 397-408
Published: June 25, 1979
Released on J-STAGE: March 19, 2009
JOURNAL FREE ACCESS1. The process of vitellogenesis in an air breathing fish, Channa punctatus has been studied using histochemical tests for proteins, carbohydrates, lipids and nucleic acids.
2. The results indicate two categories of compound yolk formed during vitellogenesis, one-the intravesicular and the other intervesicular yolk.
3. The intravesicular yolks develop within yolk vesicles and are composed of polysaccharides including glycogen, protein and RNA. In mature oocytes, these yolks occupy a peripheral position and the smaller variants of such yolk form the cortical alveoli lying just below the vitelline membrane which might participate in the process of fertilization.
4. The intervesicular yolks are in the form of spherical globules which fill in most part of the cell except a zone of peripherally displaced PAS positive intravesicular yolk bodies and are mainly composed of proteins and lipoproteins.
5. Both nucleolar extrusions and extra-oocytic materials brought into the oocyte by maternal circulation and entering through endocytosis contribute to the formation of intervesicular yolk.
6. The appearance of ‘yolk nucleus’ in the early oocytes and its disappearance in mature oocytes is speculated to be involved in the process of yolk deposition.View full abstractDownload PDF (2582K) -
Sudarshan Chaudhry1979 Volume 44 Issue 2 Pages 409-418
Published: June 25, 1979
Released on J-STAGE: March 19, 2009
JOURNAL FREE ACCESSThe salivary gland chromosomes of Anopheles ramsayi, a wild strain from the forest inhabitations of North-east India (Gauhati, Assam), are described and a standard chromosome map is given. The diploid karyotype and the banding pattern of the salivary chromosomes are compared with that of Anopheles stephensi stephensi. The metaphase karyotype is a modified “gambiae-type.” The salivary chromosome arms 2R, 2L and 3R have the maximum similarities between A. ramsayi and A. stephensi stephensi, whereas X-chromosome and autosomal arm 3L are completely independent in their banding pattern in A. ramsayi. The sum total of all the homologies suggest that in its phylogenetic relationship A. ramsayi is only distantly related to A. stephensi.View full abstractDownload PDF (1198K) -
I. Gamma-raysK. Vedajanani, Y. S. R. K. Sarma1979 Volume 44 Issue 2 Pages 419-427
Published: June 25, 1979
Released on J-STAGE: March 19, 2009
JOURNAL FREE ACCESSThe material Spirogyra azygospora (n=12: chromosomes polycentric) beloging to the Order Conjugales, was used as an experimental material to study the morphological and cytological effects of gamma-rays. The doses administered range from 2 kR to 130 kR. Even the dose of 130 kR gamma radiation did not prove to be completely lethal to this alga. Among the various cytological effects chromosome and chromatid breaks, chromatid and isochromatid exchanges and ring, chromosomes are noteworthy. Chromatid and isochromatid exchanges are reported for the first time in polycentric chromosomes. The results were discussed with those of others who studied the effects of ionizing radiations on the karyology of algae.View full abstractDownload PDF (1123K) -
II. Ultraviolet lightK. Vedajanani, Y. S. R. K. Sarma1979 Volume 44 Issue 2 Pages 429-435
Published: June 25, 1979
Released on J-STAGE: March 19, 2009
JOURNAL FREE ACCESSThe material Spirogyra azygospora (n=12: chromosomes polycentric) was used as an experimental material to study the morphological and karyological effects of UV light. Different doses of UV light administered range from 5.22×103 ergs/mm2 to 52.2×103. The doses 52.2×103 ergs/mm2 and 26.1×103 ergs/mm2 proved to be completely lethal and sublethal doses respectively to this alga. Morphological and karyological effects were recorded. Among the cytological observations, chromatid and isochromatid exchanges are noteworthy; and are reported for the first time in polycentric chromosomes after UV irradiation. Effects induced by UV light are discussed with those reported for other algae by earlier workers. Spirogyra azygospora was found to be more sensitive to UV light in comparison to gamma-rays. Possible reasons for such a differential response to gamma and UV radiations by the same alga have been discussed.View full abstractDownload PDF (1063K) -
K. Vedajanani, Y. S. R. K. Sarma1979 Volume 44 Issue 2 Pages 437-447
Published: June 25, 1979
Released on J-STAGE: March 19, 2009
JOURNAL FREE ACCESSThe material of Spirogyra azygospora Singh was exposed to different doses of UV light ranging from 5.22×103 ergs/mm2 to 52.2×103 ergs/mm2. 52.2×103 ergs/mm2 and 26.1×103 ergs/mm2 proved to be completely lethal and sublethal doses respectively to this alga, coupled with 24 h dark incubation. Sensitivity of the alga to UV light, and effects of different periods of dark incubation (0-24 h) after UV treatment were also studied; such studies being first of their kind on a filamentous green alga. Extent of survival was a dose dependent process, irrespective of the period of dark incubation. UV effects were clearly observed with all the doses administered, even when the irradiated materials were immediately exposed to light without any dark incubation. At the same time, phenomenon of photoreactivation also plays an important role in reversing the adverse effects caused by UV light. A minimum of 12 h dark incubation was found to be necessary for non-functioning of the phenomenon. Relative sensitivity of three desmid taxa, Closterium lanceolatum f. minor f. nov., Cosmarium cyclicum and Euastrum cornubiense f. major f. nov., to UV light was assessed on the basis of their percentage survival to different doses of UV light. The doses of 78.3×103 ergs/mm3 and 156.6×103 ergs/mm2 proved completely lethal to Closterium lanceolatum f. minor f. nov. and Cosmarium cyclicum respectively, whereas the same exposure (156.6×103 ergs/mm2) proved to be sublethal dose for Euastrum cornubiense f. major f. nov. The observations in the present study are discussed in the light of earlier existing data on other groups of algae.View full abstractDownload PDF (716K) -
Toshiaki Kameya1979 Volume 44 Issue 2 Pages 449-456
Published: June 25, 1979
Released on J-STAGE: March 19, 2009
JOURNAL FREE ACCESSIn order to clarify conditions of plant cell fusion, dextrans with various molecules were examined with protoplasts of different developmental stages. Dextrans were not toxic for protoplasts and high molecular dextran is possible to induce both protoplast aggregation and fusion by adding electrolyte such as inorganic salts. Fusion occurred among young leaf protoplasts more frequently than among those of old leaf. Fusion frequncies were enhanced by pronase E treatment of protoplasts, even among old leaf protoplasts. As the times went by after stopping pronase E treatment, fusion frequencies decreased by degrees. These facts appeared that protein accumlated during ageing of cells on plasmamembrane and played a part in preventing plant cells from fusion.View full abstractDownload PDF (1072K) -
VI. Karyotypes of thirteen species in the genus NotropisJ. R. Gold, C. W. Whitlock, W. J. Karel, J. A. Barlow1979 Volume 44 Issue 2 Pages 457-466
Published: June 25, 1979
Released on J-STAGE: March 19, 2009
JOURNAL FREE ACCESSWe have examined karyotypes from thirteen species of the North American cyprinid genus Notropis: N. chrysocephalus, N. fumeus, N. longirostris, N. lutrensis, N. oxyrhynchus, N. roseipinnis, N. sabinae, N. shumardi, N. signipinnis, N. texanus, N. umbratilis, N. venustus, and N. volucellus. All thirteen species have 2n=50 chromosomes. Estimated haploid arm numbers among the thirteen species ranged from 46-50; one-armed chromosomes (centromeres subterminal to terminal) comprised only a small portion of the karyotype of each species. Chromosomal evolution in Notropis, and in North American Cyprinidae, has been remarkably conservative. Almost all species karyotyped have 2n=50 chromosomes, and with one exception, cyprinid species with 50 chromosomes vary in estimated haploid chromosome arm number from only 46-50. In contrast, speciation in these fishes appears to have been rapid. Thus, the present data suggest that gross chromosomal rearrangement has played only a very minor role in the speciation and evolution of these fishes.View full abstractDownload PDF (2053K) -
Kumkum Sikka, A. K. Sharma1979 Volume 44 Issue 2 Pages 467-477
Published: June 25, 1979
Released on J-STAGE: March 19, 2009
JOURNAL FREE ACCESSChromosome studies were carried out on 28 species and varieties belonging to 18 genera of Brassiceae after evolving special pretreatment techniques. In general the tribe is characterised by a graded karyotype with medium to short chromosomes and constrictions mainly median to submedian in position.
In the subtribe Brassicinae, eight genera with chromosomes ranging from 14 to 36 in the somatic nuclei have been studied. Different base numbers have been observed and the same genus often shows more than one number. Intraspecific variations are on record. Four genera under the subtribe Raphaninae investigated have chromosome numbers ranging from 2n=16 to 60. In the subtribe Cakilinae, 2n=16 chromosomes are present in two species of a genus investigated.
In the subtribes Vellinae and Moricandiinae 2n=16, 28 and 36 chromosomes have been observed.
In the tribe Brassiceae, various base numbers namely, 6, 7, 9 and 10 have been observed but it is difficult to determine which one is more primitive. In evolution, polyploidy has been encountered in many cases. Aneuploidy is even more frequent. Gene mutation has been responsible for stabilisation and diversification of genera. The role of structural alteration of chromosomes is comparatively less in the diversification of major taxonomic units.View full abstractDownload PDF (621K) -
S. M. Jorapur, A. L. Kulkarni1979 Volume 44 Issue 2 Pages 479-485
Published: June 25, 1979
Released on J-STAGE: March 19, 2009
JOURNAL FREE ACCESSIn the present investigation, the reports on chromosome numbers and karyomor-phology of the five species viz: E, reticosa, E. mysorensis, E. exilis, E. microchilos and E. dalzellii are made for the first time. The occurrence of ‘B’ chromosomes in E. microchilos and E. dalzellii is also a first time report. Basic numbers for the species in the genus Eria, are proposed on the basis of the present study and early reports. The possible evolutionary line showing the relationships of and amongst the species is also proposed, considering the morphological and cytological characters.View full abstractDownload PDF (895K)
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