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K. Apparao, K. T. Ramavarma
1974 Volume 39 Issue 3 Pages
379-382
Published: September 25, 1974
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S. T. Mercy, S. N. Kakar, J. B. Chowdhury
1974 Volume 39 Issue 3 Pages
383-390
Published: September 25, 1974
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Cytological studies were carried out in three species of genus
Cicer,
viz;
C. arietinum,
C. soongaricum and
C. pinnatifidum. The chromosome number of
C. arietinum and
C. pinnatifidum was confirmed to be 2n=16. The reported number of 2n=14 for
C. soongaricum could not be confirmed and in the present material, the number was established as 2n=16. The presence of one pair of satellited chromosomes in
C. arietinum and
C. pinnatifidum was confirmed and instead of the reported number of two pairs of satellited chromosomes, only one pair was found in
C. soongaricum. The average chromosome lengths of the different species were calculated. A significant difference in the size of the smallest pair of chromosomes in
C. pinnatifidum as compared to that in
C. soongaricum and
C. arietinum, was found. This can be used as a distinguishing feature of the
C. pinnatjdum complement whereby it can be identified from the complements of
C. arietinum and
C. soongaricum.
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P. Sreenivasa Rao
1974 Volume 39 Issue 3 Pages
391-395
Published: September 25, 1974
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In
Gelidiella acerosa (Forsskal) Feldmann et Hamel a count of 8 chromosomes has been obtained in the vegetative cells of the thallus and a reduced number of four has been observed in the prophase of the second meiotic division of the tetrasporangium. Moreover, the characteristic “diffuse stage” or “growth stage” of the nucleus observed by many workers in all tetrasporangia undergoing normal meiosis has also been met with in this alga. It can therefore be stated that the tetrasporangium undergoes normal meiosis. The tetrasporophyte is thus a diploid phase of the plant, while the spores produced by it are haploid. Hence, there is a clear indirect evidence of the existence of the haploid sexual phase, which is the currently missing phase.
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S. Krishnaswami, P. Madhava Menon
1974 Volume 39 Issue 3 Pages
397-402
Published: September 25, 1974
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Cytomorphological investigations were carried out in four species of
Barleria and all of them showed the chromosome number 2n=40 with regular meiosis. There were significant discontinuous differences in morphology between the species studied.
The interspecific hybrid secured between
B. prionitis and
B. noctiflora was vigorous with profuse branches and it had a greater number and large sized flowers with a long blooming period. The hybrid had the same chromosome number (2n=40) as that of the parents and the meiosis was normal. The gross homology of the genomes of the two species is evident from the chromosome association in the hybrid. The female fertility of this hybrid was, however, considerably reduced and the causes of female sterility appeared to be complex.
The barrier to isolation in different species studied were mainly in the nature of cross-incompatibility mechanism. This mechanism appeared to be incompletely developed and reinforced by hybrid inviability.
The possibility of producing interspecific hybrids offers scope for artificial introgression. The interspecific hybrid reported herein has greater ornamental attributes than the existing forms.
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U. Subhashini, D. M. Gopinath
1974 Volume 39 Issue 3 Pages
403-409
Published: September 25, 1974
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Intersubgeneric crosses were made with the newly discovered Australian species
N. umbratica (n=23), with a view to find out the taxonomic position and phylogenetic relationship. The karyotype studies of
N. umbratica revealed, that the species fits in the section
Suaveolentes, forming a bridging link between the 22 and 24 paired species. Meiotic studies of the F
1 N. paniculata×
N. umbratica showed low pairing and hence distant relationship of the two species involved in the cross. The amphiploid
N. paniculata-umbratica (2n=70) is stable and bred true for 5 generations. This amphiploid supports Goodspeed's (1954) postulate, that the further expansion of the genus above 24 paired level is possible by amphiploidy.
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S. P. Vij, N. Vohra
1974 Volume 39 Issue 3 Pages
411-417
Published: September 25, 1974
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Zeuxine strateumatica was presently investigated with five cytotypes (2n=20, 42, 50, 60, 100). Polyploidy, though, was correlated with gigasness of the features, the different cytotypes often overlapped each other in their morphological characters. In the polyploid taxa hypo and hyper-ploid pollen cells resulted from multiple associations and non-disjunction of chromosomes and multipolar spindles.
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M. P. Misra
1974 Volume 39 Issue 3 Pages
419-427
Published: September 25, 1974
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Ottelia from four different localities belonging to Nothern India, have been studied in the present work with the aid of improve method. Detailed study of karyotypes have been included within the scope of investigation. Special emphasis has been laid on the study of different populations of the same species to assess the role of structural alternations in the chromosomes in the evolution of different populations.
Species of
Ottelia are remarkable in the sense that the populations differ with respect to the external morphology of the plant.
The diminution in chromatic matter along with polyploidy has been an associated feature of evolution in different families of flowering plants. The same is true in case of
Ottelia. Hetrochromatic elimination appears to be more probable explanation for diminution in chromatic content, in this light of evidences so far obtained.
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Omotoye Olorode
1974 Volume 39 Issue 3 Pages
429-435
Published: September 25, 1974
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Chromosome counts are reported for 39 collections of Gramineae representing 35 species and 24 genera.
First chromosome counts are presented for
Loudetia sp.,
Brachiaria deflexa,
B. stigmatisa,
Panicum comorense,
Anadelphia leptocoma,
Andropogon ascinodis A. pseudapricus,
Jardinea congoensis, and
Sorghum lanceolatum. New chromosome counts are presented for
Dactyloctenium aegyptium,
Panicum maximum,
Pennisetum pedicellatum,
P. purpureum and
Hemarthria altissima.
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Manuel Uribe, Alfredo Laguarda, Jorge Romero, Jorge Paulete, Susana Sc ...
1974 Volume 39 Issue 3 Pages
437-442
Published: September 25, 1974
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The authors report the cytogenetic analysis of
Neotomodon alstoni alstoni (
Rodentia,
Cricetidae), an endemic species restricted to the transversal vocanic system of Mexico. The chromosome number of this species is 2n=48 and the fundamental number NF=66. From the cytogenetic point of view,
Neotomodon alstoni alstoni shows close relationships with the genus
Peromyscus because several species of the latter show 8 pairs of biarmed autosomes as the former, as well as the same chromosome number and identical fundamental number. The analysis of male meiosis in spermatocytes shows 23 bivalents, while X and Y chromosomes having short pairing segments form an end-to-end synapsis. The X-Y complex shows negative heteropycnosis in the X component which seems to be related to their allocyclic portion during this phase of cellular cycle. The Y chromosome shows discrete positive heteropycnosis.
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M. S. Chennaveeraiah, S. G. Bharati
1974 Volume 39 Issue 3 Pages
443-451
Published: September 25, 1974
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In the classification of Charophytes by Wood (1962, 1964) and Imahori (1965) many taxa have been amalgamated into a system reducing their number. There is no complete support for this as revealed in our study on the four taxa of
C. gymnopitys A. Br.. Cytologically they have different chromosome numbers and distinct karyotypes and are at different levels of polyploidy. These need to be given the distinction of different taxa and the names given to them by Zaneveld (1940) seem justified. Polyploidy seems to have played an important role in the mechanism of speciation in this group.
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Pai-hsi Pi, Chuan-ying Chao
1974 Volume 39 Issue 3 Pages
453-465
Published: September 25, 1974
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The present study is concerned with the microsporogenesis at two different polyploid levels in two polyploids (one spontaneous and one induced) of
P. longifolium, and three (two spontaneous and one induced) of
P. commersonii. In
P. longifolium the octoploid plants (2n=80) induced from the desynaptic tetraploid biotype (2n=40) are synaptic. In
P. commersonii, the hexaploid (2n=60) and dodecaploid (2n=120) biotypes are asynaptic and synaptic respectively, while the dodecaploid (2n=120) induced from the asynaptic hexaploid biotype is completely asynaptic. The results indicate that meiotic pattern, and consequently method of reproduction, can be changed after chromosome doubling. Although the microsporogenesis in the synaptic taxa follows a normal meiotic pattern, irregularities such as the presence of univalents, multivalents, multipolar spindles, laggards, etc. are common. As a result, the percentage of pollen abortion is relatively high in these taxa. In the desynaptic and asynaptic taxa, univalents during MI asynchronously move first toward the poles and then back to the equator and the first meiotic division ends in the formation of a restitution nucleus, while the second division is rather regular. Two unreduced microspores are formed from each microsporocyte at the end of microsporogenesis with relatively low pollen abortion. The causes of modification of meiotic pattern after chromosome doubling, univalent behavior during the stage between diakinesis and equatorial grouping of univalents, and presence of anaphase II bridge in both taxa of
P. longifolium were discussed.
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Reciprocal translocation induced by colchicine
T. S. Dhillon, Elvera K. S. Dhillon
1974 Volume 39 Issue 3 Pages
467-472
Published: September 25, 1974
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Growing points of four weeks old seedling of
Phlox drummondii were smeared with 0.5% emulsion of colchicine in lanolin. One plant out of 20 survivors was found to be a chimera; branches developing from cells treated with coichicine showed an interchange complex of four chromosomes whilst those originating from untreated cells were cytologically normal. Cytogenetical properties of the reciprocal translocation are presented and the possible mechanisms by which colchicine could have induced the reciprocal translocation are discussed.
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S. S. Raghuvanshi, A. K. Singh
1974 Volume 39 Issue 3 Pages
473-482
Published: September 25, 1974
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Dry seeds of
Trigonella foenum-graecum were irradiated at 10 to 60 KR. Germination percentage, rate of growth, pollen fertility and seed setting were investigated in M
1. Chromosomal aberration and chromosomal mosacism were noted at 40 KR. Lethals, steriles, semisteriles, dwarfs and some promising variants were isolated in M
2.
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Minakshi Banerjee
1974 Volume 39 Issue 3 Pages
483-491
Published: September 25, 1974
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Four species under two genera of the family Pontederiaceae have been investigated, namely,
Eichhornia crassipes, Solms. (2n=32, n=16),
Monochoria hastaefolia, Presl. (2n=28, n=14),
M. vaginalis, Presl. (2n=1 52, II 26, III 80, n=III 40),
M. vaginalis, Presl. var.
plantaginea, Solms.-Laubch. (2n=52). In
Eichhornia crassipes 2n=32 chromosomes and n=16 bivalents have been observed in different populations of this species. Such a regular constancy in chromosome number in a species with extensive vegetative propagation is quite remarkable. The evidences so far obtained indicate that polyploidy, aneuploidy and structural changes of chromosomes have played effective roles in the evolution of species of
Monochoria. The study of the two genera shows that even though n=16 is deep seated for
Eichhornia and n=13 or 14 for
Monochoria the two genera certainly represent a natural assemblage under Pontederiaceae as suggested by the taxonomists. This is principally shown by their karyotypes which have remarkable similarities in the gross morphology with each other.
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M. L. H. Kaul, A. K. Bhan
1974 Volume 39 Issue 3 Pages
493-498
Published: September 25, 1974
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Cuscuta reflexa-eine blattlose, wurzellose, parasitische Kletterpflanze-wurde als eine Kombination einiger verschiedener kürzlich ermittelter Subvarietäten erkannt. Die vorliegende Arbeit schildert die zytologischen Eigenschaften eines Zytotyps der Arten mit n=16 and 2n=32 Chromosomen, welche auf
Bougainvillea glabra Chosy wuchsen. In der Metaphase variiert die Länge der somatischen Chromosomen von 10, 42 bis 23, 06μ. Der Chromosomensatz setzt sich zusammen aus acht metazentriscen, vier submetazentrischen and vier subterminalen Chromosomen paaren. Während alle subterminalen Chromosomen klar and eindeutig als die kürzesten zu erkennen sind, ergibt sich in bezug auf die anderen Chromosomen eine allmählich stufenlose Abnahme in der Gesamtlänge. Die Chromosomenpaare 1 and 2, 3 and 4, 5 und 6 etc. bis 15 and 16 gleichen sich sehr weitgehend bezüglich ihrer allgemeinen Morphologie, des Verhältnisses ihrer Arme, ihrer relativen und absoluten Gesamtlänge. Die Meiose verläuft normal mit 16 Bivalenten während der Al, mit einer regelmäßigen ungestörten Anaphase-Trennung und ergibt demzufolge eine hohe Pollenfertilität.
Da die 7 von Darlington and Wylie (1955) als die Basiszahl für die Gattung
Cuscuta beschrieben worden ist, scheint es sich bei dem hier behandelten Zytotyp vermutlich um eine sekundäre Polyploidie mit 8 (7+1) als Basiszahl zu handeln. Das offensichtlich diploid-ähnliche Verhalten dieser tetraploiden Rasse wird wahrscheinlich genetisch kontrolliert. Dabei wird möglicherweise-ähnlich, wie es für Weizen beschrieben wurde-ein Gen wirksam, welches die Multivalentenbildung hemmt, somit die Paarung von 2 Homologen beschleunigt und die Möglichkeit für eine 3 oder 4-fache Paarung vermindert oder verhindert.
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P. K. Gupta, Ran Vijai Singh, Saraswati Rani
1974 Volume 39 Issue 3 Pages
499-505
Published: September 25, 1974
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Meiosis was studied in six collections belonging to four different species of the genus
Digitaria. Two of these four species were studied for the first time. In another species, a new chromosome number was recorded. In the remaining fourth species an earlier known chromosome count was confirmed.
Two collections belonging to
D. glauca were studied and both showed abnormal meiosis (2n=45; 2n=39). The details of meiosis in these two collections are presented and the implications of 2n=39 on the basic number in the genus were also discussed.
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VI. Effect of the insecticide “Rogor” on the mitosis of Vicia faba and Gossypium barbadense
Soheir M. Amer, Odette R. Farah
1974 Volume 39 Issue 3 Pages
507-514
Published: September 25, 1974
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The effects of the insecticide o.o-dimethyl-N-methyl-carbamido methyl dithiophosphate “Rogor” were studied on root-mitosis of
Vicia faba and
Gossypium barbadense. Two types of treatments were conducted: seed-soak, and root-treat. ments. Both pure and formulated “Rogor” effected a great decrease in the mitotic index of
Vicia faba when compared with the control. The percentage of abnormal mitoses in beans induced by formulated “Rogor” was much higher than that induced by the pure substance. Recovery experiments showed that roots treated with pure “Rogor” recovered more rapidly than those treated with the formulated substance. Disturbed prophases, meta and anaphases comprise the most dominant type of anomalies in both beans and cotton, lagging chromosomes were also observed in both plants. Chromosome contraction was observed only in cotton. Chromosome stickiness, chromosome fragmentation, anaphase bridges, and multipolar anaphases were observed only in
Vicia faba.
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Nancy E. Peterson, Sandra Bell
1974 Volume 39 Issue 3 Pages
515-524
Published: September 25, 1974
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It was found that RNA synthesis was markedly inhibited in
Vicia faba root tip cells after treatment with 5×10
-5M hycanthone. DNA synthesis was slightly inhibited while protein synthesis was not affected.
Following a three hour treatment with 10
-5M and 5×10
-5M HC, a decrease in mitotic indices was observed four and eight hours after removal from the chemical. The inhibition was reversible and cells appeared normal after 12 hours of recovery. A treatment of 10
-5M and 10
-6M HC for two hours did not significantly affect mitotic indices, whereas a concentration of 10
-4M HC consistently resulted in virtually total inhibition of cell division and root development.
No aberrations were found above control level in cells exposed to 5×10
-5M HC. In cells exposed to 10
-5M HC immediately following radiation, the numbers and proportions of aberrations observed were not significantly different from aberrations found in cells which received X-ray treatment only.
When irradiated cells were treated with 5×10
-5M HC, a concentration causing only slight mitotic inhibition, the result was an almost total decline in cell division and cessation of root growth. Treatment with 10
-5M HC after radiation resulted in no discernible mitotic inhibition.
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B. B. Chimphamba
1974 Volume 39 Issue 3 Pages
525-529
Published: September 25, 1974
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This work is concerned with chromosome studies in three species of
Moraea and two species of
Dietes, all of which are being introduced into cultivation as ornamentals in Malawi. Karyotype analysis for the species is given which has shown that the two genera are very different in chromosome morphology. The results, while confirming previous determinations of chromosome numbers in these genera have also added chromosome reports of
Moraea thomsonii (Thumb.) Ker. which were unknown before. A preliminary report on the induction of polyploidy is given and lines of further research to obtain interspecific and intergeneric hybrids are indicated.
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Kwong-yu Chan
1974 Volume 39 Issue 3 Pages
531-536
Published: September 25, 1974
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The ultrastructure and division of the pyrenoids in a green colonial alga
Coelastrum sp. was investigated. The pyrenoidal matrix consists of three components: helical fibrils, dense granular particles measuring 50-60Å in diameter and interspersed electron transparent areas. There are no tubules or membranes within the pyrenoid matrix. The present investigation confirms the division of the pyrenoids in this species. The pyrenoid is divided into two portions by apparent intrusive growth of the starch plates around the pyrenoid girdle. A circular furrow develops on the surface of the starch plates, expands centripetally, and cuts the pyrenoid into two.
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Susan Abraham
1974 Volume 39 Issue 3 Pages
537-542
Published: September 25, 1974
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The effects of high concentrations of cowdung in sand on cell division and gene mutations have been studied in
Tradescantia clone O2. The frequency of somatic mutations induced in the staminal hairs has been found to increase with increase in the concentration of cowdung in the sand. Chromosome breakage resulting in deletion of large and small segments of chromosomes from the daughter nuclei and spindle abnormalities of various types were oberved in the treated plants. It is possible that mutations in the staminal hairs result from deletion of the dominant allele for flower colour. The possible role of decaying organic substances like compost, cowdung and oil cakes in the induction of spontaneous mutations in nature is also discussed.
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Kalyan B. Datta
1974 Volume 39 Issue 3 Pages
543-551
Published: September 25, 1974
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Seven taxa belonging to two species of
Iberis have been dealt with in the present scheme of work. Members of
I. amara reveal uniformly 14 chromosomes, while all the four varieties of
I. umbellata have 18 chromosomes in their somatic complements indicating the existence of basic complements with 7 and 9 chromosomes. Results show close relationships between the basic sets and suggest as well the probable derivation of 9 from 7. The complement of 7 chromosomes may be regarded as primarily basic to the genus
Iberis.
In spite of the remarkable constancy of chromosome number in the varieties of a species, they, however, differ in the details of chromosome morphology suggesting that structural alteration of chromosomes has also been an important factor in diversification of the genus. Most primitive karyotype is represented in
I. amara from which other species and varieties might have evolved through aneuploidy and structural changes of chromosomes.
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S. M. Stack, C. R. Clarke
1974 Volume 39 Issue 3 Pages
553-560
Published: September 25, 1974
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By using an
in situ DNA denaturing-renaturing technique for differential Giemsa staining of root chromosomes of
Allium cepa, telomeres were specifically stained. In meristematic cells, the position of the telomeres intranuclearly indicates that chromosomes remain polarized from anaphase through prophase of the following division and that nuclear rotation is rare during this time. In contrast, non-mitotic cells one centimeter proximal to the root tip also retain chromosome polarization, but the nuclei apparently are capable of rotation. We suggest that non-rotation of nuclei is one aspect of the polarity of the root meristem.
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II. Sub-family Eragrostoideae
J. Christopher, A. Abraham
1974 Volume 39 Issue 3 Pages
561-571
Published: September 25, 1974
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This paper deals with cytological observations made on 29 species belonging to 15 genera of the subfamily Eragrostoideae. This includes first reports on 14 species. The basic chromosome numbers recorded are 5, 6, 9, 10 and 12. The existence of two cytological types has been observed in
Sporobolus indicus.The present cytological findings justify the separation of the genus
Eragrostiella from
Eragrostis by Bor (1940) on the basis of morphological characters.
Sporobolus is probably derived from
Eragrostis by alterations in basic chromosome number as suggested by Brown (1950). The tribes Eragrosteae and Chlorideae are closely interrelated and it is probable that these two tribes have originated from the same ancestral stock. The Pappophoreae and Zoysieae are highly specialised members of the Chloridoid-Eragrostoid group.
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Nucleic acids, phospholipids and phosphatases in the female reproductive organs of chemosterilised Poecilocerus pictus
S. C. Saxena, Vikram Aditya
1974 Volume 39 Issue 3 Pages
573-580
Published: September 25, 1974
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M. V. Reddi, G. M. Rao
1974 Volume 39 Issue 3 Pages
581-584
Published: September 25, 1974
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Idiogram and number of chiasmata/bivalent were obtained from
Capsicum annuum L. from premetaphase stage of tapetal cells before microsporogenesis. The individual length of chromosomes ranged from 8.6 to 14.8μ. The heterochromatin part of the shortest chromosome is the nucleolus organizer; the longest chromosome has a satellite. Of the 12 chromosomes, eight have submedian centromere, three subterminal and one median. The three shortest chromosomes have heterochromatic short arms.
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B. Balarami Reddy, M. V. Reddi
1974 Volume 39 Issue 3 Pages
585-589
Published: September 25, 1974
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Cytohistological studies conducted with male sterile lines Tift-23 A, 628-A and their maintainer lines of pearl millet (
Pennisetum typhoides) revealed that meiosis was normal and degeneration of microspores occurred in the sterile lines after separation from tetrads.
There were no differences in the thickness of epidermis of the anther walls in male sterile and maintainer lines. In respect of endothecium and tapetum differences existed, A-lines had thin endothecium initially but increased in thickness towards pollen maturation, while it was the reverse in the B-lines. Tapetum attained its maximum thickness at meiosis in all the lines and degenerated completely towards the anther dehiscence with the exception of Tift-23 A where tapetum remained persistent and vacuolated.
Male sterility was associated with thicker endothecium. Male sterility was also associated with tapetal persistence in ms Tift 23-A but not in ms 628-A.
Increased application of nitrogen resulted in increasing the thickness of endothecium and pollen sterility in maintainer lines.
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V. N. Naik
1974 Volume 39 Issue 3 Pages
591-596
Published: September 25, 1974
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The cytological details of
D. montanum Baker and
D. saxorum Blatter have been presented. Both these species are at diploid level.
D. montanum has 2n=20, 12 and 10, while
D. saxorum has 2n=12 and 14 chromosomes. Variable chromosome numbers in both the species are probably due to the presence of B-chromosomes.
Irregular behaviour of chromosomes at meiosis and poor stainability of large precentage of pollen grains indicate high degree of sterility in these species. Regular bivalents were observed only in about 5-7% of the PMCs.
Formation of fruits and the development of viable seeds is very rare and propagation appears mainly through underground bulbs. Both the species have unstable genotype and appear active from evolutionary stand point.
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Muzammil Ahmed
1974 Volume 39 Issue 3 Pages
597-607
Published: September 25, 1974
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The chromosome number in the marine gastropods
Nucella lamellosa,
N. lima and
N. canaliculata is 70 (n=35). Chromosome analysis of about two hundred individuals from natural populations gave evidence for the occurrence of:
1. pericentric inversions leading to the production of heteromorphic bivalents.
2. centric-fusions (only in
N. lamellosa) resulting in the formation of large and medium-large metacentric ring-bivalents in place of rod-bivalents in only few cells (4%) of individual snails.
3. Floating interchange heterozygosity or associations of non-homologous or partly homologous chromosomes giving rise to rings of 4-6 chromosomes, open linear and zig-zag quadrivalents and trivalents and univalents occurring in a limited number of plates.
In none of these cases, however, is there any evidence for a regular polymorphism associated with differences in microhabitat equivalent to that known in
N. lapillus.
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G. K. Manna, R. Prasad
1974 Volume 39 Issue 3 Pages
609-618
Published: September 25, 1974
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Caryotype analysis, metrical study and centromeric index of somatic chromosomes from the kidney of three gobiid fishes,
Boleophthalmus glaucus,
Glossogobius giuris and
Gobioides rubicundus and the meiotic chromosomes from the testes of first two species have been investigated. All the three species have 2n=46 chromosomes but the morphology and the metrical data were different.
B. glaucus had chromosome formula of 6m+10sm+1st+4t+2T and the measurement of the chromosomes ranging between 2.99±0.55 and 1.34±0.15 micra,
G. giuris had 2t+21T and measurement between 2.35±0.35 and 1.30±0.17 and
G. rubicundus had 1m+13s+5st+3t+1T and measurement between 2.66±0.32 and 1.59±0.11 micra. No clear indication of sex chromosomes was found either in the somatic or in the germinal cells. Meiosis was stereotype with the bivalents clearly seen from the diakinesis stage. Chromosomal evolution and interrelationships in the three species have been discussed and the role of pericentric inversion in bringing the morphological differences in the caryotype has been stressed.
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