Bud Clusters Research Articles

A tissue culture technique for vegetative propagation and low temperature preservation of Beta vulgaris

A tissue culture technique for clonal propagation of Beta vulgaris is described. Flower buds or flower bud clusters formed adventitious shoots on half-strength Murashige & Skoog's medium supplemented with 10 μmol/l benzyladenine (BA). The shoots were multiplied by axillary bud proliferation on a medium with 1 μmol/l BA and rooted on a medium with 10 μmol/l indolebutyric acid. The plants were vegetative. No mutations were observed. Genotypic variation was found in shoot formation, shoot multiplication and rooting. Some genotypes showed leaf malformations which were attributed to BA. Rooted plants in culture tubes could be stored for one year at 2 or 5°C and a low light intensity.

The development of the lung in the pig‐tail monkey (Macaca nemestrina,L.)

AbstractThis study covers the period from the fortieth day after ovulation to the thirty‐eighth day after birth. In addition, lungs of two mature monkeys have been analyzed. Birth occurs about the one hundred sixty‐eighth day (24 weeks after ovulation). By the fortieth day the patterns of the bronchopulmonary segments are well established. These are the tools of the investigator. The curve of growth for the first 60 days parallels that of the rhesus monkey but is steeper than the human curve. At 63 days (9 weeks) pairs of rosette‐like clusters of epithelial buds (future alveolar ducts) have appeared on peripheral branches of the segmental bronchi and continue to grow in size until the twelfth week. Then they resemble the paired rosettes of human acini of the seventeenth postovulatory week (Boyden, ′74) and probably represent the primitive unit from which the human was derived. In both man and monkey, canalization of the rosettes starts at about the same relative time (the 17th and 12th week, respectively) and spreads centralwards from the rosettes along the bronchioles of each segmental bronchus. In man, canalization forms acini (alveolar ducts and respiratory bronchioles). In the monkey, due to the monopodial pattern of branching, it produces racemes of alveolar ducts, each raceme ending basally in a pseudorespiratory bronchiole (127th day). By the one hundred fortieth day, enough surfactant has been secreted to support a premature infant. At one hundred fifty days, 11 generations of bronchi, followed by 16 of pseudorespiratory bronchioles, are present in the medial basal segment, followed in turn by 19 generations of prealveolar ducts (the latter provided with delicate spiral muscles) each giving off alternate branches of alveolar ducts. After one hundred fifty days of gestation, generations of bronchi, pseudorespiratory bronchioles, prealveolar ducts and cartilages (15) remain virtually constant for at least 38 days after birth. By the adult stage the number of generations of pseudorespiratory bronchioles has been reduced to three and the prealveolar ducts increased (at the former's expense) to 27. This study is concluded with a comparison of the lungs of the newborn monkey with those of the human/neonate and puppy.

Detection of simian type-C particles in Mason-Pfizer virus infected cultures.

A simian type-C virus has been detected in cultures chronically infected with Mason-Pfizer monkey virus (M-PMV). Simultaneous budding of M-PMV and type-C virus particles from the same cells was observed in cultures incubated at 37 or 40 degrees C. However, the frequency of such cells was greater in cultures grown at 40 degrees C. Although clusters of type-C viral buds were seen at the surface of the cells, extracellular mature type-C particles in cell pellets or concentrated virus preparations were very rarely found. The increase in frequency of type-C buds was found to be transitory since cultures adapted to growing at the high temperature demonstrated budding type-C particles only occasionally. Cultures producing type-C buds were found to contain, in addition to M-PMV antigens, serological activity with polyvalent antisera produced against multiple structural components of endogenous baboon virus (BV) or simian sarcoma virus (SiSV). The reactivity, however, was found not to be serologically related to the major SiSV P28 core protein.

Perturbation of mammalian cell division: human mini segregants derived from mitotic cells

Mitotic HeLa cells can be induced to undergo abnormal cleavage and to give rise thereby to clusters of buds and/or to free mini segregants. A wide range of morphologies can be produced and the mini segregants vary considerably in size and structure. Some contain DNA which may or may not be enclosed in a nuclear membrane. This DNA in some of the mini segregants originates from dense ‘chromatin bodies’ which migrate to the periphery of the parental cell at an early stage of mitotic perturbation. The percentage of mitotic cells which undergo abnormal cleavage is affected by a number of factors including the pH of the medium, the presence of dithiothreitol or certain other thiol compounds, the absence of serum and storage of the mitotic cells at 4 °C before treatment. To date, the optimal conditions are: incubation at 37 °C in Hanks solution buffered at pH 8.0–8.4, after storage of the mitotic cells for about 3 h at 4 °C. Under these conditions about 70 % of the total mitotic population undergoes abnormal cleavage to produce clusters of mini segregants in the course of an incubation period of 3½ h. Possible mechanisms underlying the phenomenon are discussed.

Studies on the post-initiation development of flower buds of tomato (Lycopersicon Esculentum)

SummaryThe application of high temperature (ca. 70° F., 21° C.) to tomato plants for varying periods prior to first anthesis showed that:1. Inflorescence abortion occurred when high temperature (and low light) was applied in the late stages of development of the inflorescence. Similar treatment in the early stages, up to the time when the first cluster of buds could be seen by the naked eye, did not induce abortion.2. In low light conditions, equivalent to those occurring naturally at mid-winter, an initial period of high temperature (70° F.) followed by low (60° F., 15–5° C.) induced a greater flowering capacity than constant low temperature.3. The beneficial effects on flower development resulting from early high temperature treatment were greatest when the day temperature was high, though some benefit also resulted from a high night temperature. The effects were evident only with early (October) sown plants. There was no apparent adverse effect on flower development of high temperature applied up to the “visible bud” stage (2,250 kilolux hours).

PHYTOKININS AND SENESCENCE IN BROCCOLI

The respiratory pattern of broccoli bud clusters treated with N6‐benzyladenine at harvest or at daily intervals thereafter was similar to that of at‐harvest‐treated broccoli. The treatment effect did not diminish with time but was conditioned by the degree of physiological degeneration of the tissue prior to treatment. Respiration quotients indicated that the rate of oxidative decarboxylation and phosphorylation was reduced in tissues treated with N6‐benzyladenine. Higher organic phosphorus content was observed in treated tissue, and 2,4‐dinitrophenol overcame the N6‐benzyladenine‐induced respiration inhibition. It is suggested that the mode of action of phytokinins on respiration and senescence inhibition was due to a conservation of adenosine triphosphate in treated tissue.

Incorporation and effects of thymidine analogues in gametophytic tissue of Arbidopsis thaliana

The incorporation of 5-iododeoxyuridine into gametophytic cells of the primary bud cluster of Arabidopsis thaliana was detected by section autoradiography of buds treated for 24 μ1 of a solution containing 125I-labelled 5-iododeoxyuridine mixed with 3 · 10 −4 M 5-iododeoxyuridine abd 1 · 10 −6 M 5-fluorodeoxyuridine. Heaviest incorporation was in the megagametophytic cells of the primary bud but pollen mother cells of some anthers also incorporated the analogue. Incorporation in such labelled mother cells was higher in the nuclei than the cytoplasm, as measured by silver grain distribution over these cells. 5-fluorodeoxyuridine and/or 5-bronmodeoxyuridine applied at the primary bud stage prolong onset flowering and inhibit growth. These effects can be overcome by an application of thymidine. Progeny in segregations from some plants treated with 5 · 10 −4 M 5-bromodeoxyuridine in combination with 5 · 10 −7 M 5-fluorodeoxyuridine and 5 · 10 −a M deoxyguanosine showed a response to selection for viable seedling laggards versus nonlaggards, and the frequency of “lethal laggard” seedlings was also higher in these selected lines than in control populations and nonlaggard selected lines. The possibility that this effect was due to genetic changes caused by the analogue treatment is presently unresolved in view of the probability of nongenetic lesions causing similar phenotypes.

Ingrown sprouts in potato tubers: Factors accompanying their origin in Ohio

The factor or conditions necessary for the internal growth of sprouts observed in Ohio appear to be these: (a) An agent which injures and destroys the dominance of, the apical meristem of exposed sprouts, without completely inhibiting the expansion of basal portions of such sprouts, and without inhibiting the development of unexposed buds. (b) A set of circumstances which allow the full force of the expanding sprout to be exerted on the periderm. This condition may be satisfied by the pressure of another potato against the eye of origin, by the mechanical components of a basipetally expanding cluster of buds, or by one or two less complex means.

Biology of the Superb Plant Bug, Adelphocoris superbus (Uhl.) (Hemiptera: Miridae), in Southern Alberta

The superb plant bug, Adelphocoris superbus (Uhl.), is a serious pest in some alfalfa seed fields in southern Alberta. It feeds on the unopened bud clusters, causing them to whiten and die (bud-blasting). Under cages, it has also caused flower-drop, stunting of plants, and destruction of immature seed (Sorenson, 1954). When numerous it may prevent fields from producing enough bloom for the alfalfa pollinators in the vicinity, and in such numbers is of economic importance to the seed-growers. The number of bugs necessary for an economic population thus varies inversely with the pollinator population on the field.

Response of several varieties of potatoes to different photoperiods

Results of the studies conducted with 9-, 11-, 13-, and 17-hour photoperiods in the greenhouse indicate that the different photoperiods have little effect on the diameter of the stems in the potato plants. There was, however, a significant difference in the height of the plants,—the tallest plants being produced with the longest light period. There was a highly significant difference in the number of bud clusters produced per plant by the 17-hour and all the remaining treatments. The different photoperiods had no effect on the percentage of fertile or stainable pollen. The plants in the 17-hour photoperiod produced the most buds for pollination and developed the most seed balls and the largest weight of both seed balls and seed.

Studies of Natural and Artifical Parthenogenesis in the Genus Nicotiana

1. Seed giving plants true to the maternal species in the F1 generation accompanied by aborted seed probably hybrid in nature, was found when certain Nicotiana species were cross-fertilized. Hybrid plants and plants purely maternal were obtained from the same capsules in other crosses. 2. The capsules of several Nicotiana species were caused to swell slightly by merely tickling them with a sharp-pointed instrument, but no seeds were produced. 3. Abortive seed probably without embryos was produced by singeing young buds with a hot platinum wire, by the exposure of young plants to chloroform gas, and by cutting away a portion of the pistil and pollinating the stub both with and without the accompaniment of a germinative fluid. 4. Abortive seed was produced by shortening the pistils of a flower and grafting the stigma end of another pistil on to the stub and pollinating the same. 5. The ringing of the branches below a cluster of buds did not assist in the production of seed. 6. No seed was produced by the si...