The paper relates to the observations made on the gametic contributions from the male and female sides in a number of intra and interspecific crosses in Saccharum and crosses with allied genera. The findings are as below:- 1. Chromosome numbers in all F1s of intraspecific crosses involving five S. spontaneum variants, namely, S. spontaneum (Coimbatore), S. spontaneum (Glagah), S. spontaneum (Holes I), S. spontaneum SES 248 and S. spontaneum S.H. 546 (Egypt) indicated functioning of only haploid gametes on the part of both the parents. 2. When S. spontaneum Coimbatore was selfed, a few giant forms with three times the haploid chromosome number of the parent were obtained in addition to a large number of diploid plants with n+n gametic constitution. The functioning of diploid egg gametes is therefore to be inferred in the former. 3. The species S. barberi and S. robustum were also found to contribute only haploid gametes in both way crosses with S. spontaneum variants. But, S. officinarum was generally found to contribute the diploid egg gametes in crosses with S. spontaneum, except when crossed with certain variants G. 3009-Uganda (2n=120) and S. spontaneum S. H. 445-Ceylon (2n=128). 4. In crosses between S. spontaneum and a few hybrid cane varieties having some spontaneum chromosomes in their genetical make up the functioning of only haploid gametes was observed. However, one instance of functioning of diploid egg gamete on the part of the pistil parent, POJ. 2725 and two cases, viz., Co. 421×S. spontaneum Coimbatore, Co. 421×S. spontaneum Glagah wherein egg gametes with a deficient haploid number had functioned were noticed. 5. Functioning of both 2n+n and n+n gametes was observed in interspecific as well as intergeneric crosses, viz., S. spontaneum×S. offacinarum and S. spontaneum×Sclerostachya, Narenga and Erianthus. 6. The functioning of n+n as well as 2n+n gametes was noticed in crosses between different varieties belonging to the same species and even in selfs. It would therefore, appear that gametic contribution is unsuitable as a criterion of genetic relationship between the types involved in crosses. 7. It may be possible to use the gametic contribution of a clone as, an additional criterion along with morphological and anatomical characters for identification of its species.
The present communication records observations on the cytoplasmic inclusions of the uropygial glands of the pigeon and the domestic duck. During the course of present investigations, classical ‘Golgi techniques, ’ morphological techniques of known chemical reactions and other current histochemical techniques have been employed. The mitochondria, which are of usual lipoproteinous nature, are in the form of rods or filaments, each having one or more surface granules. These surface granules detach themselves from their respective mitochondrion, grow in size, get vacuolated and serve as sites for the condensation of neutral lipids (secretion). Every secretion droplet is invariably ensheathed by thin lipoproteinous membrane with which are sometimes seen associated granules of similar chemical nature. There has been observed a gradual decrease in the cytoplasmic basiphilia (RNA) and cytoplasmic affinity for Hg-BPB and PAS colourations from periphery towards lumen, whereas reverse is the case with sudanophilia. In the lumina, in addition to the secretory products (neutral lipids), the presence of proteins and carbohydrates has also been detected. There has been observed nothing which could even remotely be compared with the much publicized ‘apparato reticolare interno’ of Golgi.
Plant populations derived from seed resulting from open-pollination of the putative hybrid, Agroelymus turneri, have been within progenies:-(a) uniformly similar to Agropyron repens; (b) uniformly similar to Elymus canadensis; or (c) segregated in plants similar to Agropyron repens, A. dasystachyum and Elymus canadensis. Seed-set following self-pollination of Agropyron repens-like plants varied from 0 to 7%; open-pollination fertility varied from 23 to 72% in the F2 population derived from seed produced at Madison and from 27 to 44% in the Fort Saskatchewan population. Elymus-like plants averaged 44% selffertility; fertility following open-pollination was not obtained. Florets of Agropyron dasystachyum-like plants were 11% self-fertile compared to 35% cross-fertile. Seed formed in some A. repens-like plants characterized by low levels of pollen stainability. There was no evidence from studies of the developing female gametophyte that indicated any form of apomixis was operative. Microsporocyte development studies indicated elimination of sporocytes due to the accumulation of extraneous materials in the thread mass during prophase stages of development, i.e., prophase lethality. Sporocytes progressing further than metaphase I were generally quite regular in their meiotic divisions. The forms of sterility encountered may be due to an unbalanced enzyme and amino acid synthesis brought about by the fusion of dissimilar gametes. Sterility appeared to be related to the interaction of nucleus with the noncomplimentary cytoplasm.
The variation of the length of the mitotic cycle had been studied in normal haploids, in different types of diploids, and in artificially produced binucleate and other cell types of diverse Micrasterias species. The cycle is shortest in some double cells with a relative large number of plasmastructural units. In some cases also the diploid may divide at the highest rate. In double cells a short interval occurs when only one end of the cell has divided in the preceding division and the other end has hence had time to reach maturity earlier than the former. The mitotic cycle is shorter in haploid than in diploid cells. The uniradiate haploid cells divide at a lower rate than normal biradiate haploid cells and, at least in some species, biradiate diploid cells at a lower rate than triradiate diploid cells. In the binucleate cells, including the heterocaryotic types, i.e. cells with one haploid and one diploid nucleus, the mitosis takes place simultaneously at both isthmuses. The dependence of the mitotic cycle on the nucleocytoplasmic ratio and the mitogenesis problem are discussed.
A comparative study of cytology and morphology revealed that the cytologically reduced as well as unreduced gamete of B. intermedia can be fertilized by a normal gamete of D. annulatum to produce viable offspring. The 2n=40 chromosome D. annulatum appears to be a segmental allopolyploid with the chromosomes of the two genomes sufficiently homologous to pair when present in the haploid condition. The 2n=40 chromosome B. intermedia is regarded as a segmental allopolyploid with a number of D. annulatum genes incorporated in the one genome.
In course of cytological investigation a heteromorphic pair of chromosomes was observed in one of the plants Belamcanda chinensis growing in the garden. The pairing behaviour of the heteromorphic pair was studied in detail from the onset of meiosis. At diplotene one chiasma was invariably observed in the heteromorphic arm of this bivalent but at metaphase I in many cases this bivalent did not show any chiasma in that arm, presumably the chiasma has slipped off. The frequency of reductional and equational separation studied at anaphase I conformed to the Mather's formula for n=1. The diplotene configuration of this bivalent supports the partial chiasma type theory of crossing over.
1. Two populations of Heliotropium ophioglossum Stocks ex Aitch. were studied cytologically and polyads observed. Univalents as well as cytoplasm appear to be responsible for the formation of polyads. 2. The origin of these cytological abnormalities seems to be hybridization and uniformity in the cytoplasmic malfunction may be because of apomixis.
1. The present communication furnishes cytological information on the male meiosis in Plea frontalis Fieb. and P. metiadusa Dist. belonging to the family Pleidae (Heteroptera) which was so far unknown, cytologically. 2. The diploid number of chromosomes is twenty three in both the species and the sex determining mechanism is XO-type in the male. 3. The status of the Pleidae and Anisopinae (Notonectidae) has been discussed in the light of cytological data presented in this paper.
Studies were made on the changes of spleens, lymph nodes and livers of mice related to the antibody formation in response to antigen injection; use was made of cytochemical and cytophotometric methods. The heat-killed cells of the Yoshida ascites tumor of rats mixed with Freund's adjuvant were used as antigen. The antigen showed a capacity to elicit the antibody formation in mice leading to the elevation of antibody concentration in the circulating blood. The mouse spleen after a single subcutaneous injection of the antigen material showed a marked cellular reaction in the form of an increase in number of basophilic cells in the red pulp. The basophilic cells contained a large amount of RNA: they may play a decisive role in the antibody formation and correlate with the increased value of serum agglutinin titers. The change of lymph nodes was also remarkable in that they showed increased basophilia in lymphatic cells. The change of livers was characterized by an increase in amount of nucleic acids and by the subsequent depletion of glycogen and phospholipids after the antigen injection. The livers may take some roles, primarily or secondarily, in the antibody production.
The present paper deals with a morphological and cytological study of free cells native to the coelomic cavity of newts, Triturus pyrrhogaster, by phase-contrast microscopy. The coelomic free cell population of newts consists of cells with Russell's bodies (40-55%), histiocytes (40-50%), leucocytes, lymphocytes, and mast cells. Cells with Russell's bodies are characterized by bipolar protoplasmic process and cytoplasmic inclusions. They were roughly classified into four types according to the shape of the cytoplasmic inclusions. There was no mitotic figure in cells with Russell's bodies in the normal coelomic fluid of newts. Cell division of free cells was induced through repeated daily abdominal punctures. There was a decrease of free cells with an increase of mitotic frequency following the stimuli in combination with the injection of hypotonic solution. The successive stages of mitosis were followed serially in cells with Russell's bodies, and in three other kinds of free cells. Cells with Russell's bodies showed 24 chromosomes in both sexes.
The chromosome complement in vegetative and female gametophyte tissue of Pseudolarix amabilis was determined to be n=22, and 2n=44. The 22 chromosomes are made up of 20 I-shaped and 4 V-shaped chromosomes. It is postulated that this condition arose from the breakage of 10 V-shaped chromosomes at the centromere from an original complement of n=12.
Eggs of Gryphaea (Crassostrea) gigas (Thunberg) were used at their early stages of growth when the polar bodies had not yet been formed. Lipids and glycogen were detected cytochemically. It is worth mentioning that the distribution of both glycogen and unsaturated lipids agrees with the second physiological gradient axis in fertilized eggs. This fact suggests that such a creative area as will shift the germinal vesicle and will increase the metabolic activity under the control of the nucleus, may exist in the cytoplasm near the animal pole.
Gigas-plants are assumed to appear from nullisomic dwarf wheat as a result of chromosome aberrations in MI. Various chromosome aberrations in MI and unequal distribution in AI of ag-dwarf lines were observed and chromosome aberration rate, theoretical and observed appearance rates of gigas were compared for seven dwarf lines. Except the g-dwarf (Dwl, 5), theoretical appearance rates of gigas are too small against the observation, amounting to 5-10%. There are many factors involved, such as competitive fertilization, elimination of dwarfs and others. Still more important is the fact that the special chromosomes which are homoeologous to the deficient one, become easily aberrant. In the case of b-dwarf, the special chromosome is a Sat-chromosome which becomes very often a univalent.
Detailed analysis of chromosomes at pachytene and later stages of meiosis were made in five species of Sorghum belonging to the Sub-genus Eu-Sorghum. Pachytene chromosomes are depicted on the basis of relative length, centromeric position, arm ratio and number of chromosomes which are adjoining the darkly staining region. The idiogram of all the five species which is represented diagramatically do not exhibit much variation. Pachytene chromosomes exhibit differentially staining regions which persists till late diakinesis. The nucleolus organizer in all the Eu-sorghums so far studied, is situated on the short arm of the first chromosome close to the centromere except for the species S. arundinaceum were it is located on the long arm. The possible cause for such difference is discussed. Studies on the pairing properties of the differentially stained regions show that synapsis starts from proximal to the distal end and separation of split chromosomes starts from the distal and proceeds to the proximal. The distribution of chiasmate at different stages was studied. The average frequency of chiasmata per cell between different species show no significant difference. A critical analysis of the bivalents at diakinesis revealed that chiasmata are absent or rarely present in the deeply staining region. If such a localization prevails, it would mean, recombination of the genes located in the heavily stained regions would be highly restricted, to the non-staining regions. Based on the idiogram of the pachytene chromosomes the possible role of chromosomes in speciation and the relationship between species are discussed.