1. Since IAA stimulates the growth and cycocel acts as retardant for the growth of the roots we set out to determine whether is any interaction between CCC and IAA (indol 3-acetic acid) in the effects they produce on mitosis. 2. After 4 hours combined treatment of IAA in the previously mentioned concentrations and 12, 000 ppm CCC, there is a depression in the mitotic indices. Cells fixed one hour later after the above mentioned combined treatment show an increase in MI. On the other hand cells fixed 2 hours later showed a decrease in MI. This trend in decrease the MI continues in the following 4 hours. 3. Sticky in the highest concentrations, C-anaphases-micronuclei and multinucleated cells are the types of abnormalities which were observed after the combined treatment of IAA with 12, 000 ppm CCC. 4. The treatment of Vicia faba root cells with 400 ppm IAA and 12, 000 ppm CCC, causes the formation of tetraploid cells and multipolar anaphases in relatively high frequency. 5. The data from roots treated with cycocel indicates that this treatment induce alternation in the duration of mitotic cycles of cells. We have concluded that these alternations occur from changes in the numbers of cells in prophase and metaphase and the numbers of tetraploid metaphases seen in treated roots. On the other hand this change can be counteracted by supply different concentrations of IAA to a relatively moderate concentration of cycocel. 6. In addition a partial antagonistic effect was reported after treating Vicia faba roots with 600 and 400 ppm IAA and 12, 000 ppm CCC. This finding agrees with the results of other investigations who concluded that antagonism between any two substances was never total.
In the marine dinoflagellate Ceratium furca, the duration and the percentage of mitosis were observed in culture. The periodic cell division with mitosis is strictly confined to the border from dark to light under the light regime of 12 hours each. The rate of mitosis scarcely varies in relation to the change of temperature between 15°C and 25°C. On the bases of long persistence of the prophase nuclei, the charac-teristic feature of the stages III and IV, lack of discernible spindle and the equtorial plate, the nucleus of C. furca may be considered as eukaryote which retains certain Cyanophyceae-like features.
The ontogeny of the septal nectary in Dipcadi montanum and Allium cepa is studied employing histochemical staining techniques for the localization of polysac-charides, nucleic acids and proteins. Morphologically, the septal nectary makes its appearance because of the incomplete union of the adjacent carpels at this region. To begin with, the nectary cells resemble their neighbouring cells of the septum in having low level of polysaccharides, but rich RNA and proteins. The starch grains accumulated in the nectary cells, at the 4-nucleate embryo sac stage, of D. montanum get degraded as the female gametophyte grows and attains maturity. The cytoplasmic RNA and proteins are at a higher level in the nectary cells than in their neighbouring cells, at 4-nucleate, 8-nucleate and mature embryo sac stages. These substances are diminished and lost completely in the cells of the septal nectary of the developing fruit. Thus the increase in the activity of the septal nectary seems to have a direct relation with the development of the female gametophyte and decreases gradually to cease finally in the post-fertilization stages of development. The secretion of nectar from the septal nectary and insect pollination are apparently biological coincidents.
Observations on the nuclear behavior during chlamydospore development in Phaseolus mungo L. and Sesbania grandiflora Pers. by Protomycopsis patelii Pavgi and Thirumalachar and Protomycopsis thirumalacharii Pavgi respectively are described in detail. The vegetative cells and/or conidia from diploid mycelia are pathogenic in the 2 species. Numerous chlamydospores typical of the species form the terminal sporogenous cells of the permeating hyphae within the infection epicenter. No vascular infection was noted. No haustoria were developed by any of the species. Pathological effects were observed on the host cells without any stimulation for cell multiplication and enlargement. Comparison was made on chlamydospore development in species of allied genera in the family Protomycetaceae.
Pycniospore transfer experiments were carried out in Ravenelia breyniae Sydow on Melanthesa rhamnoides Blume and R. sessilis Berkeley on Albizzia lebbek Benth. The 2 rust species appear homothallic. Dikaryotization is effected by cellular fusion in R. breyniae and by nuclear division in R. taslimii Mundkur.
The present paper dealt with some histochemical observation on the basal substance of the insoluble state of anthocyanin appearing in the upper epidermal cells of petals, using a black rose cultivar, Charles Mallerin. The results obtained are summarized below. 1. The satisfactory fixation and decoloration of the insoluble state of anthocyanin were accomplished by Müller's solution, 10% neutral buffered formalin and Scott's solution, leaving a massive structure. 2. The insoluble state of anthocyanin treated with the solutions above mentioned was stained orange with safranin, and red with ruthenium red very strongly. 3. These stainings are strongly suggestive that the pectic substance is involved in the basal substance of the insoluble state of anthocyanin. 4. It may be considered that the pectic substance of this massive structure is not calcium salt of pectic acid but protopectin. 5. The insoluble state of anthocyanin in the present material can be interpreted as a special structure of the pectic substance, protopectin, associated anthocyanin.
Analysis of chromosome behaviour at meiosis in Crepis capillaris, 2n=2x=6+B-chromosomes, shows that the B-chromosomes influence the frequency and distri-bution of chiasmata in the A-chromosomes. The mean chiasma frequency of the A's is increased by the presence of one to four B's, so too is the variance of the chiasma frequency mean between the pollen mother cells within plants. The A-chromosome bivalents differ in length, but all have similar mean chiasma frequencies, and they are all influenced to the same extent. Some data are also presented on the meiotic behaviour of the B-chromosomes themselves. Many of them get eliminated as micronuclei.
1. The diploid number of chromosomes in Ophisops elegans is 38-36 macro-and 2 micro-chromosomes in the males and 35 macro- and 3 micro-chromosomes in the females. 3. The sex determining mechanism is of the ZZ: ZW type. The Z-chromosomes are represented by the smallest pair of macro-chromosomes and the W-chromosome consists of the micro-chromosome which is even smaller than the pair of micro-chromosomes (pair 19).
1. A tetraploid Allium cepa originating from a Bangladesh stock is described. 2. Comparison with the diploid stock shows that the low frequency of bridge and fragment formation, and micronuclei present at meiosis, has been replaced by a very high frequency of both, in the tetraploid. 3. Evidence is presented that it is an autotetraploid, the result of fusion of unreduced gametes, or of parthenogenesis. 4. The tetraploid is characterised by a bi-modal size range of pollen grains, and complete sterility.
1. The estimated duration of the mitotic cell cycle of meristematic cells in the female gametophyte of Pallavicinia longispina was follows: (period) (hour) G1 3.5 S 14.5 G2 6.5 M 4.0 (prophase 1.2 prometaphase 1.0 metaphase 0.5 ana-telophase 1.3) total cell cyte 28.5 2. The first appearance of silver grains over the mitotic prometaphase chromo-somes was at 6 hour after the beginning of 2 hours pulse labelling. At this hour silver grains were only over the euchromatic regions, and not over the hetero-chromatic regions. This labelling pattern was also observed at 8 to 10 hour. The heterochromatic regions having silver grains were observed for the first time at 15 hour when euchromatic regions were also labelled. At 20 to 25 hour, the hetero-chromatic regions have more grains than the euchromatic regions. These results show that the duration of DNA replication in heterochromatin is shorter than that of euchromatin and that the heterochromatin completes its DNA replication earlier than euchromatin. 3. Differential replication of DNA is found among chromosomes in a com-plement: X chromosome completes its DNA replication earlier than any other auto-somes; individual autosomes vary in the distribution of early replicating segments.
Root-tips of garlic (Allium sativum) were used to study the effects of tobacco smoke from 11 types of cigarettes on the cytology of the cells. Of the 11 cigarettes utilized, 9 were experimental and 2 were commercial brands. The experimental cigarettes included 1R1, 1A1, 1A2, 1A3, 1A4, FO-24, FO-25, FO-30 and T-5, while of the two commercial brands used, one had 2 cm cellulose acetate filter and the other had a two part filter consisting of 1 cm activated charcoal filter and 1 cm cellulose acetate filter. Young roots from garlic bulbs were exposed to 1, 2, 3, 4, 5, 10, 15, and 20 puffs of smoke from the above cigarettes. They were then allowed to grow in distilled water for 20 hours, fixed, stained and finally observed for normal and abnormal mitotic divisions. In general, the cells of roots treated with tobacco smoke displayed disturbances of the spindle apparatus, irregular separation of chromosomes, and lagging of certain chromosomes in moving away from the equatorial plate. Increasing number of puffs resulted in a greater frequency of mitotic abnormalities. These investigations may be of importance in establishing the validity of using the incidence of mitotic abnormalities as an index of the biological effects of tobacco smoke and its constituents. These studies should eventually lead to the identification of smoke constituents responsible for the induction of irregular mitotic divisions and chromosomal aberrations. Any harmful smoke constituents which are detected by this method, could perhaps be eliminated from tobacco before it is used for the manufacture of cigarettes.
A comparative study of the development of normal and aberrant microspores of two mutants of Impatiens sultani shows that initiation of cytokinesis is not restrained by aberrations in chromosomal cycle. Although cytokinetic cleavage begins simultaneously in normal and aberrant meiocytes, delay or blockage of the progression of furrowing occurs in atypical meiocytes resulting in lobed monads and dyads. Random cytoplasmic divisions in meiocytes with scattered chromosome groups of telophase II produce spores of various sizes enclosing 0-8 or more chromosomes. Despite these aberrations in the cleavage phase, all spores-even those with a single chromosome or no chromosome at all-develop pollen walls with identical exine pattern and chemical constitution, lending support to the suggested role of extrachromosomal factors in pollen wall development.
The karyotypes of three species of Chelonia of family Chelidae, from the Amazon Region of Brazil are described: Platemys platicephala, with 2n=64; Mesoclemmys gibba, whith 2n=60 and Chelus fimbriatus with 2n=50. A comparison of cyto-genetics data is made with data of other species of Chelonia. It is suggested that centric fusions or elimination of microchromosomes, or both, are an important mechanism responsible for the karyotypic evolution of Chelonia. No sex chromosome is detected in the species here studied. In male meiosis of Chelus fimbriatus, the pachytene cells showed a bivalent with a defined region lacking pairing. This defferential behavior may be taken as an indication of sexual difference.
Brachet's method for the identification of tissue DNA and RNA is very specific because the nature of the stained material is confirmed by the enzymatic extraction. However, the small sized nuclei of pollen of fruit trees (Malus, Persica, Corylus) lose their affinity for methyl green after heating for 2 hours at 37°C with RNase or distilled water (as control). RNA cannot be extracted with cold perchloric acid, because of the low specificity of this extraction. In contrast, treatment with glacial acetic acid or acetic anhydride for 18 hrs, following proper alcoholic dehydration, enhances the nuclear stainability. The recommended fixative is Navashin's, with increased concentration of acetic acid up to 30% (to remove mitochondria), for 3 hrs. After thorough washing and bleaching with mixture of equal parts saturated aqueous ammonium oxalate and 3% H2O2 the slides are incubated with either enzyme or distilled water at 37°C for 2 hrs and treated with glacial acetic acid or acetic anhydride. Staining with methyl green (B. D. H.) 0.3% (w/v) and pyronin (Merck) 0.25% (w/v) in acetate buffer at pH 4.7, is performed at 37°C for 2 hrs. Differentiation is achieved by dipping in ice cold distilled water followed by a 5-40 min rinse in two changes of t-butyl alcohol. The slides are mounted in Euparal. The acetic anhydride treatment was shown to block the amino groups of basic proteins which, otherwise, would interfere with the DNA staining by methyl green.
Six taxa belonging to four species of the genus Polygonatum and one species of the genus Disporum have been studied cytologically. New chromosome number 2n=30 has been recorded in P. geminiflorum. In addition to the earlier reports made by Mehra and Pathania (1960), one more cytotype in P. sibiricum and three more cytotypes in P. verticillatum have been found to occur in the W. Himalayas. Disporum cantoniense with 2n=14 has been recorded from Nainital hills. The possible mechanisms for alteration in chromosome number and karyotype have been suggested.
Eleven species belonging to four genera, Cyperus, Fimbristylis, Scirpus and Kobresia have been studied. Four species, namely, Cyperus exaltatus (n=48), C. eleusinoides (n=52), Fimbristylis tenera (n=20) and Kobresia royleana (n=40) have been worked out for the first time. New chromosome number has been recorded in Scirpus pauciflorus (n=23+0-3B). Three base numbers x=8, 9 and 13 have been suggested for the genus Kobresia.
The effects of the two commonly used condiments, ginger and turmeric on cell divisions in root tip cells of onion have been studied. The predominant type of aberration in both cases was chromosome breakage. C-mitosis, somatic segregations, multipolar anaphases etc. were also observed. The present study has shown that extracts of fresh rhizomes of Zingiber officinale (ginger) and Curcuma longa (turmeric) are radiomimetic and may be mutagenic.
The effects of the pesticides: O, O-dimethyl-N-methyl-carbamidomethyl dithiophosphate “Rogor”, O-isopropyl-N-phenyl carbamate “IPC” and “Duphar”, (active ingredients 0.7% CIPC and 0.3% IPC), have been studied on: meiosis, pollen viability and yield of Vicia faba (var. Giza 1) plants for two (or three) successive generations. Two types of treatments were conducted, seed-soak and spraying plants at the seedling and flowering stages. The effects of the pesticides on mitosis for successive generations have been also investigated. Spraying Vicia faba plants with sat. IPC solution at the flowering stage induced a relatively high percentage of abnormal PMCs. The most attractive effect of “Rogor”, “IPC” and “Duphar” was the induction of multipolar All and TII in addition to the other types of anomalies (stickiness, ana- and telophase bridges, and lagging of chromosomes), IPC induced tetraploid PMCs also. The transmission of chromosomal aberrations to the following generations was found to be very low. The used pesticides have no harmful effect on the yield of Vicia faba plants even the treatments (seed-soak-treatments with 0.1% “Rogor” and 0.5 saturated “Duphar” solutions and spraying plants at the flowering stage with “Duphar” solution) which showed a significant inhibitory action on the yield in the 1st year did not show such effect in the 2nd generation. The 3rd generation was also normal in the case of plants sprayed at the seedling stage with “Rogor” and “IPC” solutions and showed significant increase in the yield in the 2nd generation.
A cytological investigation of meiosis in seed irradiated Cyperus eragrostis has shown that the diffuse centromeric type of chromosome organisation leads to the formation of inviable chromosome complements, in which complex configurations resulting from stickiness as well as pairing of homologous regions, and numerous fragments, persist to the formation of pollen grains. At the higher doses, however, there is complete sterility, and low fertility even at the lower doses. The small numbers of M2 and M3 plants produced at lower doses show much reduced chromosomal abnormalities, indicating severe selection among the gametes and zygotes formed. There is little advantage in terms of survival from radiation damage, resulting from the possession of the diffuse centromere.
A numerical correspondence is seen in the number of nucleolus organising chromosomes in the 4 diploid Brassica species referred in the text. Based on the numerical correspondence the allopolyploid nature of not only of B. juncea var. gracilis (n=18) and B. napus var. oleifera (n=19) but also of the three genomes ‘a’, ‘b’ and ‘c’ has been suggested. The probable origin of the nucleolus organising chromosome of ‘b’ and ‘c’ genomes from that of ‘a’ genome through a reciprocal translocation has also been suggested.
The cytology of 57 species belonging to 21 genera of the tribe Paniceae (sub-family Panicoideae) is reported in this paper. This includes 20 species which are studied for the first time. The somatic chromosomes of 29 species have been ex-amined from root tip cells and the meiotic divisions of pollen mother cells of 42 species have been studied. The chromosomes of most of the species are small-sized and about 1μ-1.5μ in length. The basic number 9 is found in 45 species and the other basic numbers recorded are 7, 8 and 10. Chromosome numbers in multiples of 8 is encountered in two species viz. Panicum maximum (2n=32) and Urochloa panicoides (n=16). About 77 per cent of the species now studied are polyploids. Intraspecific polyploidy is found in three species viz. Brachiaria ramosa (2n=36 and 72), Setaria verticillata (2n=18 and 54) and Paspalum commersonii (2n=40 and 60). The meiotic chromosome behaviour was regular in most species, but two species of Paspalum, viz. P. conjugatum and P. commersonii showed asynapsis of chromosomes. The three tribes Paniceae, Andropogoneae and Maydeae belonging to the subfamily Panicoideae have been recognised as a natural group in the recent systems of classification of the grasses. Data on chromosome numbers observed from this study and previous reports reveal that these three tribes represent one evolutionary line. It is evident that evolution of species in these tribes is accompanied by alterations in basic chromosome numbers and polyploidy.
Three alkylating agents EMS, MMS and (perhaps, for the first time) DPA have been fed to the Drosophila larvae to investigate their effects on salivary chromosomes. Heterozygous paracentric inversions are almost the only type of re-arrangement observed; hence their frequency has been considered to make certain comparisons. The relative efficiency in producing inversions indicates their reactivity in the order DPA>EMS>MMS in Drosophila. There is greater efficiency of difunctional agents over monofunctional agents; and ethylation over methylation. Armwise preference of these chemicals and different segments of salivary chromosome complement repeatedly selected for such action have been pointed out. Besides, EMS, MMS and DPA have shown similarity in affecting a few loci in common. Induction of aberrations is discussed in relation to presence of intercalary-hetero-chromatin.
By colchiploidy a number of unstable polyploids were obtained. The progeny of the unstable aneuploid 2n=67 gave a number of stable polyploids 2n=66, 68, 70, 72 in the later generations. These stable polyploids which are above the 24 paired level is a positive proof of what Goodspeed (1954) has postulated.
Twelve pairs of chromosomes of Solanum viarum Dunal are described in detail. Morphological characters of chromosomes at pachytene stage as total length, relative length, centromere index and position of eu- and heterochromatic regions are used as parameters for identification. The nucleus is not persistant at pachytene. There is complete pairing between all homologous chromosomes. There is also a striking similarity between the chromosome V and VI as well as IX and X, suggesting that chromosomes VI and IX might have been evolved from chromosome V and X, respectively through duplication. The present structure of the chromosomes could have been achieved after structural modifications had been effected through the process of meiosis during the course of evolution. Therefore, it is assumed that Solanum viarum with n=12 might have originated from a plant with n=10.
The present paper deals with a detailed cytological investigations of Chara socotrensis Nordst. in Kuhn f. noda (Pal) R.D.W. (=Chara nuda Pal) collected from a puddle at Mecheda, West Bengal, India which show some variations in vege-tative and reproductive features from the type specimen. Twentyeight chromo-somes can be seen in dividing nuclei in the antheridial filaments in contrast to the number n=14 reported earlier. A comparative analysis of vegetative and repro-ductive parts of the present specimen with those of other plants previously described from Burma and India indicate that the overall giganticism is perhaps related to its polyploid constitution. However, the karyotype of this plant reveals a number of distinctive characters, such as, the presence of two long chromosomes with supernumerary constrictions and two long chromosomes with satellites which have not been previously recorded in any Chara species. Taking morphological and cytological features together it appears that the present specimen may well be regarded as a distinct species. However, further detailed study of the karyotypes of other populations is required before a final conclusion be made regarding its taxonomic status.
Although the general fine structure of Uroglena and Uroglenopsis is not unlike that of other genera found in the Chrysophyceae, one feature was found to be of taxonomic value. This characteristic was the lack of thylakoids penetrating the pyrenoid matrix. Perhaps after more members of the Chrysophyceae are examined, the variance of pyrenoid types may not prove to be of taxonomic value at the generic or species level as in the Dinophyceae (Dodge and Crawford 1971). Comparison of the two genera to each other emphasises their great similarity with respect to general morphology and ultrastructural detail. Features which are now listed as typical of the Chrysophyceae (Hibberd and Leedale 1972) were observed in Uroglena and Uroglenopsis: plastids with three thylakoids per band, a peripheral girdle band, a layer of chloroplast ER that is continuous with the outer membrane of the nuclear envelope, flagella of unequal length (see Casper 1972), and a parabasal Golgi body.
Karyotype of Rattus norvegicus, Berkenhout from Indian environs is reported for the first time. The diploid number is found to be 42 with XX/XY sex determining mechanism X is a medium telocentric chromosome ranking 6th or 7th in order of size and constitutes 5.45% of the total haploid set. The size of the Y is found to be variable. It is either the smallest telocentric or equal to the medium size telocentric pair 11 of the group A of our classification. Chromosome polymorphism involving chromosome pairs No. 9, 12 and 13 is reported.
Echinochloa oryzicola (n=18) is an annual self-pollinated species distributed in north-east Asia and Italy as a weed in lowland rice fields. E. crus-galli (n=27) distributed widely in the world is also an annual and self-pollinated species. Cytogenetically the latter species has been assumed to be an allohexaploid derived from the natural hybridization between the former species and an unknown diploid species of the genus Echinochloa or a related genus followed by chromosome doubling. The diploid strain of E. pyramidalis was found in Kenya by the author in 1968. The discovery of the diploid strain deserves the great attention for deter-mination of the origin of hexaploid species, E. crus-galli. The Kenyan diploid strain of E. pyramidalis is a cormous perennial and is partially self-incompatible. Chromosome association at MI of the F1 hybrid between E. oryzicola and the Kenyan diploid plant of E. pyramidalis showed that the genome of the diploid plant may be related to one of the two genomes of E. oryzicola. The F1 plant was a cormous perennial and quite sterile.
Cytological studies were carried out in 14 N. Indian taxa. Centranthera hispida (n=15) and Verbascum celsioides (n=18) represent the first chromosome counts for the genus and the species respectively. Two cytomorphotypes with n=7 and n=14 in Vandellia crustacea were also unknown earlier. For the remaining taxa one or the other earlier chromosome reports are confirmed. Meiosis was normal in most of the taxa. Secondary associations were observed in Verbascum thapsus and V. celsioides. Multiple associations in Antirrhinum majus (2x) represents interchange heterozygosity. Intraspecific aneuploidy in Verbascum thapsus (2n=34, 36), Antirrhinum orontium (2n=14, 16), intraspecific polyploidy in Antirrhinum majus (2n=16, 32), Veronica anagallis (2n=18, 36, 54) and both polyploidy and aneuploidy are evident in Vandellia crustacea (2n=14, 28, 32, 42). Origin and evolution of the tetraploid taxon in the last species is discussed.
From a comparison of the chromosome numbers of different species, it appears that 11 is the basic number of Peperomia and 12 of Piper. Variation in the reports of chromosome number of the same species may be due to occurrence of chromosomal biotypes. The trend of evolution in the two genera (Peperomia and Piper) appear different, numerical and structural change in the former, and polyploidy in the latter. The basic number (x=11) is represented by Peperomia argyreia, where structural alteration is clear. x×12 is represented by Pep. metallica, Pep. obtusifolia and Pep. pellucida, polyploidy occurring only in the last one. Piper cubeba (2n=24), P. magnificum (2n=24) and P. longum (2n=48), probably form a basic group of Piper. P. nigrum (2n=36, 60) is more advanced in chromosome structure. P. betle (2n=64) represents a different line having x=8 or 16. Records of chromosome number suggest that Peperomia is more primitive than Piper.
Sieve element plastids of sugarcane were studied in their early stages of development at the electron microscope level. In their earliest forms, sieve element plastids are spherical and have a moderately electron dense stroma. They resemble the plastids of procambial cells and the microbodies found in higher plant species in regard to stroma characters and their general morphology. In later stages, pronounced changes occur in shape, size and contents of the plastids. They acquire one to several highly electron dense inclusions commonly known as the cuneate proteinaceous inclusions, which belong to P-type plastids and are charac-teristically found in sieve element plastids of monocotyledon species.
Cytological investigations were carried out in 18 species belonging to 13 genera. Teucrium quadrifarium (n=15) represents the first chromosome count for the species. New cytological types were observed in Ocimum canum (n=32+0-4B), O. sanctum (n=16+0-3B), Perilla ocimoides (n=14+0-2B) and in Calamintha clinopodium (n=20). For the remaining taxa, one or all the earlier chromosome reports were confirmed. Meiosis was normal in most of the taxa. The discordant chromosome numbers known in the family make it difficult to consider it as monobasic. Ocimum canum (8x) and Pogostemon plectranthoides (8x) represent the highest grade of ploidy. Intra-specific polyploidy is evident in Ocimum sanctum (2n=32, 64), O. canum (2n=24, 64, 128) and Ajuga macrosperma (2n=16, 32). Aneuploidy is equally common in the family at both the generic and specific levels.
The diploid chromosome number in the common house rat of Allahabad, Rattus rattus rufescens Gray., is 42 with XX/XY sex determining mechanism. The autosomes consists of 13 pairs of telocentrics (T or t) and 7 pairs of metacentrics (M or m). X is a medium-size, telocentric (T), ranking 5th or 6th in the order of length, in the complement, and constitutes 5.55 % of the total haploid length. Y is variable in size. Several karyotypic anomalies, such as the presence of an unpaired, large Sin or T chromosome, heteromorphic pair 1, close association of one of the homologues each of pairs 7 and 4, 7 and 12 and pair I and a large telocentric chromo-some, are reported.
A salivary gland chromosome map of Anopheles (Cellia) fluviatilis James is produced. This has been compared with those of Anopheles stephensi stephensi and Anopheles pulcherrimus. The X-chromosome similarities are the least, whereas 2R homologies among them are the commonest. The free ends are fairly uniform in Anopheles fluviatilis and Anopheles pulcherrimus. Anopheles fluviatilis shares a fifty-fifty relationship with pulcherrimus and stephensi.
Cason's one-step triple stain for connective tissue yields a wide range of coloration when adapted to Hydra. Previous staining methods were either time-consuming or did not adequately contrast the mesoglea, cell types, or cell inclusions. Following Bouin's or Zenker's fixative, one observes blue mesoglea apposed to red muscle fibers. Immature cnidoblasts are a light blue color; mature ones have a dark blue capsule with red coils or barb. Epithelio-muscular droplets are blue, whereas glandulomuscular droplets as well as digestive cell inclusions are orange. Nerve cells are grey. Nuclei are pink with red nucleoli, although interstitial cells and gland cells have more purplish nuclei. Mucous cells are blue after Bouin's and light lavender after Zenker's; gland cell droplets are magneta and stain well only after Zenker's. For photography on black and white film, the use of filters is demonstrated to enhance the density of desired cell types.
A number of clones of Erythronium japonicum were examined karyologically. The interphase nucleus is of the reticulate type, i.e. extremely homogeneous, with no chromocenters observed. Root tip chromosomal lengths and total genome lengths under both colchicine and 8-hydroxyquinoline pretreatments were virtually identical. All the material examined was 2n=24. Three size groups were discernible among the somatic complement, though all the chromosomes were clearly classifiable as subtelocentric. Within this asymmetrical complement, little size variation was observed in the small arms, whereas the greatest difference occurred in the long arms. Although the whole complement was subtelocentric, several of the smaller chromosomes had arm ratios close to 2:1. No nucleolar organizing chromosomes were observed for this species' complement. Based on size and centromeric position, the somatic complement can be represented as: K(2n)=24=4Lst+10Mst+10Sst. The karyological affinities of E. japonicum are with the subtelocentric, western North American species, rather than with those with metacentric chromosomes occurring in eastern North America.
1. A chromosome count of n=ca. 44 is recorded for two strains of Cylindrocystis brébissonii (Nos. 1922 and 1923 from the Culture Collection of Algae at Indiana University). 2. A complete mitosis of C. brébissonii was observed and is described along with photomicrographs for the first time. 3. Chromosome counts for C. brébissonii vary by author and it is suggested that the alga is really many species.
Investigation on nearly fifty wild populations of Nelumbo nucifera from Utter Pradesh, Bihar, West Bengal, Orissa and Assam provinces of eastern India revealed two distinct forms, varieties I and II, distinguishable florobiologically and cytologically. The karyomorphology and meiotic details of these varieties exhibited that chromosomal alterations, like inversion and deficiency have brought about differentiations of homologues, resulting into structural hybridity.