Detailed morphology and nodulating behaviour of 2n, 3n and 4n Phaseolus aureus Roxb. were worked out. Tetraploids were gigas in nature when compared to that of the diploids; triploids were intermediate. Polyploidy was found to enhance root hair infection and induced early nodulation. Number of nodules on the tap root was maximum in case of tetraploids followed by triploids and diploids whereas it was reverse when the nodules on the lateral roots were considered. During the pre-flowering stage, total number of nodules increased with the increase in the ploidy levels of the hosts but it was reverse during flowering stage. Relative com-peting abilities of the Rhizobium strains for nodule sites were found to be affected by the polyploidy status of the hosts. Number and volume of nodules were found to bear significant correlations with the volumes of the roots (tap and/or lateral).
Cytological features of nineteen taxa of both Indian wild and American culti-vated forms of Nymphaea were studied. Of these, nine members have been worked out for the first time. The chromosome counts revealed diploid, triploid, tetraploid and hexaploid levels based on x=14. N. dentatamagnifica and ‘Sunrise’ were characterised by presence of polysomaty. Majority of the taxa showed abnormalities during meiosis such as desynapsis, chromosome association and segregational irregularities, which indicate their hybrid origin.
The somatic chromosomes of seven species of Passeriformes belonging to six families have been studied. The diploid chromosome number varies from 68-80. These species possess each seven pairs of macrochromosomes, except Acridotheres tristis and Acridotheres ginginianus, which possess six pairs of macrochromosomes including the ZZ chromosomes. An identifiable W-chromosome has been found in all these species. It is either intermediate in size between macro- and microchromosomes or is of the size of the large microchromosomes. It has been found to be m, sm or T type chromosome.
Factorial analysis of variance was carried out on chiasma frequency in the genomes of Emilia Cass. using age, genome and season as the factors. Chiasma frequency was significantly greater in “coccinea” genomes than in “sonchifolia” genome; the other factors (age and season) showed no significance. There was a significant first-order interaction (season×genome) and a second-order interaction. The evolutionary significance of spontaneous chromosome aberrations in Emilia coccinea (Sims) G. Don is discussed.
Artificial autotetraploids were obtained from Emilia sonchifolia and E. coccinea. Self-compatibility tests gave results concordant with previous ones on corresponding diploids but crossability of the two species with E. praetermissa was enhanced after polyploidisation. Cytological behaviour and expression of morphological traits in crosses of the autotetraploids with E. praetermissa showed that regularity of meiosis and manifestation of phenotypic traits depend on a delicate genomic balance. A method is proposed for mapping dominant traits using chromosome loss in the genomically unbalanced hybrids.
The high basic chromosome numbers in homosporous ferns are polyploid in origin, and their haploid chromosome complements may contain two or more homoeologous sets of chromosomes (Klekowski 1973). Therefore, chromosome associations in three generations of an autotetraploid of the Venus-hair fern, Adiantum capillus-veneris, have been analysed to test the possibility of a fully penetrant genecontrolled mechanism in the so-called diploid homosporous ferns which limit chromosome associations to only bivalents. Multivalent formation occurs in the autotetraploids, which, though not unexpected, is against a simple gene control to form only bivalents. In the autotetraploid, there are relatively fewer quadrivalents and more bivalents. In the autotriploid, the frequency of trivalents compares closely with those of quadrivalents in the autotetraploids. The occurrence of large number of bivalents in the autotetraploids have been accommodated partly in the model of John and Henderson (1962) which assumes random association of chromosomes within each homologous set. Further accentuation in the number of bivalents occurs partly owing to proximal chiasmata, and partly due to a pairing restriction upon multivalent formation. Following Timmits and Rees (1971), it has been estimated that at least five of the thirty homologous sets in the autotetraploids and autotriploid of A. capillus-veneris associate themselves exclusively in pairs. Chromosome analysis in the autotriploid has also revealed evidence of non-homologous pairing, which seemingly supports the concept of “homoeologous” genomes comprising the haploid complements of extant diploid species in ferns, and also raises the probability of occasional homoeologous pairing and recombination coupled with the pairing restriction.
The Genus is dibasic with x=5 and 7. Section Verbenaca have small chromosomes where as species belonging to section Glandularia possess larger chromosomes with symmetrical karyotype. Furthermore, species belonging to the two sections are cross incompatible and all attempts to cross them were futile. The species belonging to section Glandularia, though with the same chromosome number, are dissimilar in their karyotype which speaks of the genomic differentiation during speciation. V. aubletia, a hexaploid species, has smaller chromosomes than the diploid species and has 2 types of satellites indicating involvement of at least 2 species in its origin.
Sister chromatid exchanges are studied in 17 normal animals and one carrier of 1/29 centric fusion. A mean of 12.2 exchanges per cell is found on the total animals studied. An analysis of variance done on 11 normal subjects to compare their mean number of exchanges per cell shows a significant individual difference at the 0.5% threshold. Homologous chromosome exchanges are very rare with the exception of one animal which had 4 on 8 cells studied and a quadriradial formation. The fused chromosome presents a variable number of exchanges comparable to those of free homologues.
Acrocentric chromosomes in metaphase cells of tursiops truncatus (the Atlantic bottlenose dolphin) are analyzed for satellite association and nonrandom distribution patterns. Both of these phenomena have been reported for other mammalian orders and we have previously observed them in other species of the order Cetacea. Visual examination of T. truncatus cells confirms that the acrocentric chromosomes variably display satellites and that end-to-end and rosette-like satellite associations involving these chromosomes occur in a majority of the cells. Statistical analyses of the data reveal definite associations patterns which are restricted to the acrocentric chromosomes. Further evaluation also suggests that these pairs do not participate equally in the associations and that involvement of specific acrocentric chromosomes varies among different individuals.
Among the abnormal varieties of mature spermatozoa, double or tetrad heads, monstrous heads of spheroid or ellipsoid forms with accompanying acrosomal lesions are noted. Tail deformaties of multiple or curved type are also occasionally encountered along with either complete or incomplete duplication of the core of the principal portion of the tail.
Hymenocallis littoralis (2n=46) and H. tenuiflora (2n=66) were studied cytologically and the present report of 2n=66, is new for the latter species. Both are atelocentric species. Karyotype and meiotic studies reveal the basic number as 11 for both the species and they are secondarily balanced segmental allopolyploids. Speciation is rather rapid and the major processes for evolution seem to include structural alternations like inversions and translocations; further polyploidy coupled with hybridization also might have played an important role in evolution.
River water polluted by factory effluents was tested for its cytological effects on plants. Growing plants of Ornithogalum virens were irrigated with such water and the treatment was found to produce many meiotic irregularities. The percentage of abnormalities increased from 10.2 in the control to 35.96 in the case of plants treated with undiluted polluted water, and the pollen sterility increased from 23.3% to 64.8%. Growing onion root tips when treated with polluted water produced extensive chromosome breakage, stickiness of chromosomes, and other mitotic abnormalities.
Appearance of a natural interspecific hybrid between C. colocynthis and C. vulgaris have further reinforced the close phylogenetic relationship among the two species. On the basis of available evidence it was concluded that C. vulgaris is a cultivated form of C. colocynthis evolved through mutation and selection particularly for the fruit character. The hybrid's behaviour in nature has been discussed from evolutionary point of view and also its possible exploitation for the improve-ment of C. colocynthis whose emmense economic value have been realised in recent past.
The genus Crinum is relatively stable cytologically, about 79% taxa are diploid and 21% are polyploid ranging from 3x to about 8x. The diploids are essentially karyotypically stable and while retaining a basic karyotype, the various taxa differ in the extent of heteromorphicity in the marker chromosomes like the long and nucleolar pairs. Hybridization is common and it may have been responsible for part of the karyotypic heteromorphicity both at 2x and polyploid levels. The karyotypic analysis of polyploids and the meiotic study of one triploid taxon indicate allo- or segmental alloploidy may be rather common. In view of the sterility of hybrids there appears a strong genetic differentiation between the taxa. Much of the evolution in this genus, in nature and in garden, appears to have taken place at diploid level through unequal interchanges, para- and pericentric inversions, deletions, misdivision, hybridization and above all by gene mutation. Polyploidy has not played a dominant role.
Giemsa-banding pattern of chromosomes following the BSG technique and trypsin treatment in Phaseolus vulgaris var. Tsanava Red 41 (2n=22) has been reported. Both diploid and polytene chromosomes have been dealt with. Except one metacentric pair all other chromosomes are showing either terminal or intercalary or both types of bands. One of the metacentric pairs shows centromeric band. One of the chromosomes bearing secondary constriction has been found heteromorphic. Percentage of the Giemsa-banding over the diploid complement has been calculated as 70%. This Giemsa-banding technique was found suitable for detection of the chromosomes in the karyotype which was not possible before.
Meiotic studies in 11 taxa comprising of 8 species of Polygala (family Polygalaceae) have been carried out. Five species marked* in Table 1 have been investigated for the first time and new chromosome numbers have been made available for the remaining 3 species marked+ in the same Table. A normal course of meiosis was characteristic of all the species investigated here. The genus Polygala is proposed to have been evolved from ancient stock of species based on x=7, a base number still preserved in the genus.
A technique, for studying the cytology of wheat pollen grains, was used to compare between six wheat cultivars grown in three randomized complete blocks. There was found a significant difference in number of abnormal pollen grains among the six cultivars. The percentage of abnormal pollen grains may explain the differ-ence in pollen viability among wheat cultivars. Among the six cultivars studied, Saber Beg had the least number of abnormal pollen grains and Sonora 64 had the highest.
In this report the author has enumerated the differences in interpretations of the mitosis studied both in fixed preparations and in in vivo observations. The author especially maintains the opinion that any movement of chromosomes in mitotic cells should be reinvestigated thoroughly by in vivo observations in the same way as studies on any movement of intracellular organelles, e.g. plastids, mitochondria, rotation of nucleus, streaming of protoplasm, etc. 1. Practically all behavior of mitotic cells described in cytology books has scarcely made reference to the genetic back-ground of the mitosis. 2. The breakdown of nuclear membrane before spindle formation in higher plants and animals is an impossibility. The nuclear membrane in eukaryotes is predicted and controlled by genes and genetic information which exist as long as the cell lives. 3. The participation of centrioles in the formation of spindle fibers and in the chromosome movement in anaphase is also a misinterpretation due to a disregard of genes and genetic information under which centrioles behave as primordia of organelles for cell movement. 4. In in vivo observations, the continuous movement of chromosomes in anaphase can be seen objectively in a three dimensional space of living spindles, whereas the same behavior of chromosomes in fixation cytology is made up by animating a series of chromosome images in sectioned plane mitotic cells in fixed preparations under observers' subjective influences. 5. The teleonomy and the cause and effect relationship among the behavior of mitotic cells, viz. reversible transformation of nuclear sap proteins, the change of nuclear contour from sphere to spindle-shape, the development of spindle background fibrils, the movement of chromosomes in anaphase by shortening of kinetochore fibers, formation of daughter nuclei, the accumulation of ATP at spindle poles, etc. are practically disregarded of the descriptions on the mitosis in current cytology books.
Two categories of compound yolks originate during vitellogenesis of Chrotogonus trachypterus. CY1 bodies originate near the peripheral ooplasm of the oocyte of stage 6 while CY2 develop in the central ooplasm of the oocyte of stage 8. Histochemically, while CY1 bodies are composed of polysaccharides (including glycogen), proteins (basic proteins, proteins bound reactive -NH2, -SS and -SH groups and tyrosine) and RNA; CY2 bodies consist of polysaccharide (including malt diastase and salivary amylase resistant glycogen and acid mucopolysaccharide), proteins (basic proteins, proteins bound reactive -NH2 group, arginine, histidine and tyrosine) and RNA.
The effect of Achillea extract on mitosis was studied in root tip cells of Allium cepa and Vicia faba. Two types of treatments were carried out, direct and recovery for different hours. Accumulation of prophases was observed in most of the direct treatments. While after recovery, accumulation of metaphases was noted. Inhibition of mitotic index appeared clearly in treated A. cepa root cells after direct treatment. While in Vicia the mitotic index was not nearly affected by the direct treatment of the extract.
The diploid somatic chromosome number in Ph. vulgaris L. is 2n=22, the length varies between 0.8-2.8μ, whereas, the polytene chromosomes found in the endopolyploid cells of the roots vary between 7μ and 60μ. Their cytological and cytochemical behaviour has been discussed including differential Giemsa staining and autoradiography. Function of these cells may be considered as “transfer as well as secretary gland”.
A suspension of Chang's hepatoma cells was inoculated into the tail vein of rats. Rats were killed at different intervals ranging from 30 seconds to 3 hours. Peroxidase-labelled goat anti-rabbit gamma globulin was applied to the tissue by an indirect method. Peroxidase-positive material was always found between the tumor cell and the endothelial lining and at the center of the ‘platelet tail’ as early as 30 seconds. Polymerized fibrin fibers first appeared at 15 minutes and more at 30 minutes. It is suggested that fibrin precursors act as a ‘glue’ for the tumor cell arrest.
Chromosome number of 45 species belonging to 12 different genera of Cyperaceae were determined through meiotic and pollen mitotic analyses. Of these 14 cases were proved to be new reports. While larger number of species were studied from Cyperus and Fimbristylis only one species from each of the genera Bulbostylis, Courtoisia, Lipocarpha and Rhynchospora had been investigated. In the light of these cytological findings the taxonomic problems in different groups of species in the family have been discussed.
Karyotypes were prepared using pachytene chromosomes in 11 species of Crotalaria (Leguminosae). This was done in view of the realization that minor difference in chromosome morphology, which can not be detected in mitotic metaphase chromosomes, would be resolved in pachytene bivalents. Karyotype asymmetry was found to be of a low order. The eleven karyotypes were placed in three categories (IA, IB and 2B) of the 12 categories recognized by Stebbins (1971). It is concluded that if C. incana (2n=14) is derived from other species with 2n=16, as suggested on the basis of morphology, a secondarily derived trend from asymmetry to symmetry will have to be assumed.
In the present work, the authors deal with the ontogenese and differentiation of myelin-like structures in the meristematic cells of the root tips of the horse bean (Vicia faba L.). Basing on the studies, they observed that myelin-like structures can differentiate by transforming of the membrane systems of different cell organelles and structures. Starting from the different ontogenese of these structures, the authors result that not all myelin-like structures have the same importance in spite of their analogical construction. They suppose that some types of myelin-like structures can participate on the lytic processes of plant cells.
This, the first investigation of the somatic karyotype of Uvularia floridana, was based on 200 cells from 2 clones and has shown a stablized 2n=12 number which differs from the 2n=14 counts that characterize the other species of Uvularia. This 2n=12 number represents a derived aneuploid reduction in the genus. For U. floridana, each of the 6 pairs is readily distinguishable. Pairs 1-4 form a sub-telocentric series with decreasing size. Pair 5 is submetacentric and also the nucleolar organizing (NOR) pair. (NOR chromosomes have not been reported for the other species of the genus.) Pair 6 is the smallest and subtelocentric. The karyotype is highly asymmetrical. To the derived karyology of U. floridana can be added its derived morphology and restricted geographical distribution.
A comparative study of the chromosomes from root-tip cells and from pollen tube generative cells in Allium fistulosum has been carried out by means of Giemsa C-banding techniques and fluorochromes. Culture of pollen tubes was carried out on the inside surface of a spitz-type glass centrifugation tube which contained suitable amount of liquid medium contained 0.02% colchicine. In root-tip chromosomes, when used C-banding techniques, deeply stained satellites and distal banded ends were observed and they were completely corresponded to the reduced fluorescence bands as for appearing site and size dimension. Centromeric bands, proximal ones in the gap on the shortest submetacentric chromosomes (SM4) and additional interstitial ones (of which chromosomes were SM4 and M3) were found occasionally in the C-banding patterns. Inter-plant variation of C-banding patterns was observed. No organ specificity was recognized in both the karyotype and the C- and Q-banding patterns between the chromosomes from root-tip cells and pollen tube generative cells. Several difficulties present in the banding techniques applied to the pollen tube generative nucleus were discussed.
Polyembryonic seeds of Lilium regale E. H. Wilson were induced by X irradiation of the pollen with 500 r. Mitotic analyses of 55 plants arising from the polyembryonic seeds disclosed that two sets of identical unattached twins were heterozygous for different gross deficiencies. Highly atypical flowers were produced by the deficient plants. Smaller deficiencies, beyond the limit of detection, undoubtedly were present in other sets of twins. Two sets of conjoined twins occurred. Increases or decreases in the number of floral parts were numerous; both members of a set of twins had similar flowers, indicating a common origin. It is concluded that X-ray induced deficiencies were responsible for cleavage during embryological development and the subsequent formation of atypical flowers.
In a study of the progenies derived from mono-trisomic genotypes of Avena sativa (2n=6x=42), the effect of deletion of a chromosome was more deleterious than a duplication on plant height and yield components. The combination of a duplication and deletion in nulli-trisomic progenies did not produce a more deteri-mental effect than in nullisomic condition. All other genotypes which were monosomic for each chromosome of the complement were as vigorous as the euploid one's and showed a relatively high degree of fertility. Meiotic behaviour of euploid and aneuploid genotypes clearly indicated that diploid-like pairing was under genetic control, but not completely dependent upon allopolyploidic origin. Homologous chromosome pairing ensured regular assort-ment and disomic inheritance together with consistent maintainance of genetic duplication.
The available data concerning the differentiation of the pericycle in the primary root tip of Pisum sativum, variety ‘Alaska’, may be summarized as follows. 1) The root tips from 3 to 4 day old seedlings germinated in a darkroom at 24°C were fixed with Lillie's buffered neutral formalin under green light at between 2 and 4 P.M. May 17, 1976. 2) By applying a combination of Lillie's formalin fixation together with methyl blue and/or Heidenhain's hematoxylin and safranin, the initial symptom of triarch xylary procambium appeared in a procambial cylinder in the transverse section of 250μ from the apical initials. 3) Deeply stainable protoplasts of several layers of the pericyclic cells which were localized outside of the xylary procambium show a separation from the thin cell wall. The author would like to designate as ‘α-cells’ these stainable pericyclic cells. The α-cells were localized in the area 550μ to 2150μ from the apical initials. 4) Three to six pericyclic cells in which the protoplasm scarcely stained with the dye solution should be designated as ‘β-cells’. The triarch β-cell zone was localized in a limited area, 550μ to 1750μ from the apical initials. Two or three sieve elements were observable inside of the β-cells. 5) By applying a combination of the Lillie's formalin fixation and methyl blue staining, small spherical granules take a deep blue stain in the cytoplasm of the β-cell. 6) The β-cell which contains these granules were interspersed within a limited area of the root tips.
Somatic chromosomes of two cytotypes of P. triflorum are reported (2n=22 and 2n=33). This is the first report of chromosome number for this species. The position of the satellites and secondary constrictions are the same in both diploids and triploids and on the basis of this and complete morphological identity of the chromosomes an autoploid origin of the triploid is suggested.