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71.
Summary An immunohistochemical study was performed to determine the capacity of early fetal pituitaries to differentiate into specific hormone-synthesizing tissue in the absence of any influence from the central nervous system. Rathke's pouches from rats were removed from their juxtadiencephalic position on day 11 and 12 of gestation and maintained for 2–7 days in a chemically defined culture medium (M 199) without antibiotics and serum supplementation. The immunocytochemical observations provided evidence for the differentiation of ACTH-, TSH-gb-, LH-gb-, FSH-gb-, GH- and PRL-synthesizing cells in the isolated organ cultured from 11 to 12-day-old pituitary primordia. The appearance of specific hormone-synthesizing cells in vitro displayed a delay of 1.5–2 days compared to the day of appearance in vivo, however, the sequential order of developmental events occurred as observed in vivo. The present results suggest that endocrine or neuroendocrine signals are not required for the expression of specific secretory functions of fetal pituitaries, at least at an age of 11–12 days. 相似文献
72.
Abstract. The authors have previously shown that cell treatments causing intra-cellular alkalinization stimulate the in vivo phosphorylation of a 33-K Dalton polypeptide (33 KP) (Tognoli & Basso, 1987). Here, the authors report that this polypeptide belongs to a protein associated with the microsomal membranes. They show that treatment of cells which induce intracellular alkalinization stimulate 33-KP phosphorylation, whether the phosphorylation is performed in vivo (cells loaded with 32 Pi before treatments) or in vitro (microsomes from control and treated cells, incubated with γ32 P ATP). In both cases, 33 KP is phosphorylated on a serine residue. Microsomes do not show any phosphatase activity towards this phosphorylated protein, indicating involvement of a protein kinase reaction as an effector of changes induced by intracellular alkalinization. The number of phosphorylated sites or molecules of this protein increases as a result of intracellular alkalinization, suggesting that intracellular alkalinization causes topological or conformational modifications to a protein kinase or its substrate protein. The in vitro phosphorylation is not specifically influenced by the pH of the in vitro phosphorylation medium, suggesting that protein phosphorylation is not directly controlled by cytoplasmic pH. 相似文献
73.
In the last twenty-five years, young inflorescences, floral buds and individual floral organs of a number of species have been cultured in vitro. There is considerable variability in the requirement of plant growth regulators and nutritional factors for flower development of different species. This variability is compounded by the fact that the hormonal and nutritional requirements are different at various stages of organ and floral development. Experimental studies on normal and mutant flowers in vitro have provided insights into some of the regulatory processes in floral organogenesis. The potential use of the in vitro technique in elucidating the various mechanisms in flower development is stressed. 相似文献
74.
Young leaf and internodal stem segments of Gaillardia pulchella, collected from wild species re-established in the greenhouse, were used to initiate callus on Murashige & Skoog medium supplemented
with NAA (2.0 mgl−1) and BA (0.4 mgl−1). Callus formed after 10 to 14 days in the dark. Cultures were transferred to fresh medium and placed under lighted conditions
where shoot formation occurred approximately 14 to 30 days after initiation. Callus sub-cultured at 14 to 21-day intervals
continued to produce primordia for several weeks. Flowers were produced by regenerated shoots maintained on MS medium, but
roots did not develop until the plantlets were transferred to soil conditions. 相似文献
75.
Leaves were obtained from 4-week-old seedlings of Lavandula latifolia Medicus grown in vitro. Leaf explants were then cultured on MS medium supplemented with different concentrations and combinations of the auxins IAA or NAA with the cytokinin BA and maintained under three illumination conditions, 16h photoperiod, darkness or darkness followed by a photoperiod, to assess morphogenic responses. Irrespective of illumination conditions, bud regeneration was achieved only in media containing BA or BA/auxin combinations, with the best results being obtained in the presence of BA and 0.06 or 0.6 M IAA or NAA. A photoperiod of 16h appeared to yield the best response in terms of bud regeneration percentage. High auxin concentrations (6.0 or 11.0 M) inhibited bud differentiation, especially when explants were cultured in darkness. On the other hand, low auxin levels and photoperiod improved shoot development. Excised shoots were induced to form roots by transfer to hormone-free MS medium with macronutrients at half strength. The obtained plantlets were ultimately grown in the greenhouse.Abbreviations BA
benzyladenine
- BM
basal medium
- IAA
indoleacetic acid
- MS
Murashige & skoog
- NAA
-naphthaleneacetic acid 相似文献
76.
Calli of P. argentatum were grown on a newly designed liquid nutrient flow-through system which facilitated the subculturing of calli and delayed
browning for 6 weeks. Friable calli were obtained on half-strength Gamborg B5-medium supplemented with 0.05 mgl−1 2,4-dichlorophenoxyacetic acid. Shoots developed on media supplemented with 0.2 mgl−1 benzylaminopurine but lacking 2,4-dichlorophenocyacetic acid. 相似文献
77.
Studies were performed to define tissue culture techniques and culture conditions for morphogenesis, callus culture and plantlet culture of sweet orange (Citrus sinensis (L.) Osb.), citron (C. medica L.) and lime (C. aurantifolia) (Christm. Swing). The optimal concentrations of NAA to induce root formation on stem segments were 10 mg l-1 for sweet orange and lime, and 3 mg l-1 for citron. The optimal BA concentration for shoot and bud proliferation was 3 mg l-1 for sweet orange and citron, and 1 mg l-1 for lime. Callus initiation was accomplished in a culture medium containing 10 mg l-1 NAA and 0.25 mg l-1 BA. Callus was maintained by periodical subculture into the same medium supplemented with 10% (v:v) organge juice. In vitro plantlets of the three species were obtained by rooting of shoots developed from bud cultures, and of citron and lime by development of shoots from root cultures. The plants were successfully established on soil. 相似文献
78.
Francesca Fasolo Richard H. Zimmerman Ingrid Fordham 《Plant Cell, Tissue and Organ Culture》1989,16(2):75-87
Leaves taken from micropropagated shoots of several apple (Malus domestica Borkh.) cultivars were cultured in vitro on Linsmaier & Skoog (LS) medium or the rice anther culture medium of Chu et al. (N6) containing various concentrations of either benzyladenine (BA) or thidiazuron (TDZ) plus naphthaleneacetic acid (NAA). Of the TDZ concentrations tested, 10 M was most effective and it was equivalent to, or better than, 22 M BA for both the percentage of leaves regenerating shoots and number of shoots formed per regenerating leaf in almost every experiment. Lower concentrations of NAA (1.1 and 5.4 M) gave best results with both BA and TDZ. N6 medium gave consistently better results than LS. Lowering total salt concentration or total N concentration of LS to that of N6 did not improve the response nor did changing the NO3:NH4 ratio. The 3–4 leaves on the most distal part of the shoot were most responsive and tended to form the most adventitious shoots. Placing the leaf cultures in the dark for the first 2–3 weeks of the culture period produced the best results. Optimum results were obtained by culturing leaves from the distal part of the shoot in the dark for 2 weeks on N6 medium containing 10 M TDZ and 1.1 or 5.4 M NAA, then moving the cultures to 16 h daylight at a photon flux of 60 mol s-1m-2. 相似文献
79.
M. A. L. Smith L. Art Spomer M. J. Meyer M. T. McClelland 《Plant Cell, Tissue and Organ Culture》1989,19(2):91-102
Microcomputerized video image analysis was adapted for rapid, objective, and non-intrusive quantification of shoot growth and development for plants growing in vitro. Custom-developed staging arrangements were essential to insure accurate viewing and representation of the plants in each of three standard culture vessels. Shoot length measurements from digitized culture images were strongly correlated with length measured manually ex vitro. Image analysis weighted density measurements of proliferating microcultures (even with irregular growth habits) provided a reliable indicator of shoot culture fresh weight. Non-destructive time course evaluations of growth rate and quality were demonstrated.Abbreviations FW
fresh weight
- WD
weighted density 相似文献
80.
Calli from hypocotyl and root explants of Digitalis obscura L. showed regeneration of adventitious shoots, roots and embryos when transferred to Murashige & Skoog medium supplemented with cytokinins alone or in combination with auxins. Optimum shoot-bud formation was achieved in the presence of IAA and BA, while roots mainly appeared either in absence of growth regulators or with IAA and Kn. Embryo formation took place only in those combinations that included Kn. Embryo development was influenced by the type of auxin, and precocious germination occurred in media with NAA. Mechanically isolated cells from hypocotyl- and root-derived calli were plated in MS medium supplemented with several IAA and BA combinations. Single cells were able to proliferate forming callus within 20–30 days in culture. In order to induce organogenesis, calli were transferred to various regeneration media. Shoot-bud differentiation efficiency depended on both callus origin and medium initially used for cell culture, best results being obtained in calli grown from hypocotyl-derived cells cultured in the presence of casein hydrolysate. A further subculture to medium containing coconut milk and lower concentrations of NH4NO3 and sucrose promoted shoot development. Rooting was readily achieved upon transferring shoots onto half-strength MS medium. Plantlets were ultimately established in soil.Abbreviations BA
benzyladenine
- BM
basal medium
- CH
casein hydrolysate
- CM
coconut milk
- 2,4-D
2,4-dichlorophenoxyacetic acid
- IAA
indoleacetic acid
- Kn
kinetin
- MS
Murashige & Skoog
- NAA
naphthaleneacetic acid 相似文献