Showing papers on "Murashige and Skoog medium published in 1975"

Totipotency in Tissue Explants and Callus of Some Members of the Liliaceae, Iridaceae, and Amaryllidaceae

Abstract: In vitro responses of twelve species of bulbs and corms were compared. Plantlets could be induced directly without intervening callus on stem tissue in nine species, on ovary tissue in five species, and on leaf tissue in four species. In Gladiolus, Hyacinthus, Muscari, Ornithogalum, and Scilla plantlets were formed without growth factors added to the Murashige and Skoog medium. In Hippeastrum, Schizostylis, Sparaxis, and Ipheion auxin was required. No plantlets could be induced directly on expiants of growing tissue of Freesia, Tulipa, or Narcissus. Adventitious plantlets could be induced on pieces of bulb or corm from ten species but such material was difficult to free from contamination. Callus was obtained from all species except Tulipa and Hippeastrum. Plantlets could be regenerated from callus except that of Gladiolus, Sparaxis, and Schizostylis. Differences in responses of the twelve species tend to cut across the three families and no simple relation is evident between the natural rate of vegetative increase and the in vitro behaviour.

Shoot formation in potato tuber discs in tissue culture

Abstract: Tuber discs of potato (Solanum tuberosum) growing on a modified Murashige and Skoog medium produced callus and embryoid bodies but failed to form shoots. However, if 0.4 ppm of 6-benzylaminopurine was added to the basal medium, shoots became visible seven weeks after inoculation.

Elimination of viruses from the hop (Humulus lupulus) by heat therapy and meristem culture

Abstract: SummaryA method was evolved for growing hop plants in vitro from meristem tips 0.3–0.8 mm long bearing two or three pairs of leaf primordia. Of several media tested using filter paper bridges the most satisfactory growth was obtained on a modified Murashige and Skoog medium (1962). After 10–20 days, cultures were transferred to a simplified agar medium containing auxin but no gibberellin. Using this technique two-thirds of the meristems grew into plants and 72 of 91 plants tested were free from the hop mosaic and/or hop latent viruses present in the parent plants. All clones of cv. Branding were still infected with Prunus necrotic ringspot virus but this was removed by rooting 1–5 cm shoot-tip cuttings taken from sources heat-treated at 35°C for 10 days. These techniques have been used to obtain virus-free plants of the new Wye College cultivars and are now used as routine on all new cultivars.

Isolation, culture, and fusion studies on protoplasts from different species

Abstract: Protoplasts obtained from cell suspensions of an anthocyanin synthesizing strain ofDaucus carota cv. “Rote Riesen”, cultured on a modified Murashige and Skoog medium (MS) have been induced to regenerate cell walls, and divide repeatedly to form masses of callus. Techniques have been substantially refined, and optimal conditions for the isolation of protoplasts have been established. An optimal protoplast yield of 80–90% was obtained by treating the cells with 1.5% cellulase (pH 5.0) for 4.5 hours in a gently shaking water-bath maintained at 33 °C. The protoplasts when plated in the agar-solidified medium regenerated cell walls within 2 days, and first division was observed within 3 days. In addition, they showed irregular elongation, budding and the formation of sub-protoplasts; another phenomenon was the formation of a chain of buds, which either separated from each other or formed a “coenocytic”, tube-like structure. On the agar medium which contained 0.425 M sorbitol, growth slowed down or stopped after 3–4 weeks. In order to obtain further growth, it was necessary to transfer small pieces of agar containing protoplasts on to the top of a fresh medium containing lower amounts (0.2 M) of sorbitol. The protoplasts continued to divide to form cell colonies, and finally masses of callus after 4–5 weeks. In a liquid medium (B5) the protoplasts reacted similarly, they regenerated walls within 2 days and after 2 weeks anthocyanin containing callus was formed. In both media embryo-formation occurred after 6 weeks of culture. By combining the polyethylene glycol and the high pH fusion techniques intergeneric fusion was achieved between carrot protoplasts and mesophyll protoplasts from haploidNicotiana tabacum cv. “Badischer Burley”. The fused products could be readily identified and isolated by using the difference in colour as the visual markers. Conditions for the culture of these fused protoplasts are being worked out.

Of inositol on growth and differentiation

Abstract: Effects of inositol on growth and differentiation of Haworthia tissue were studied. Inositol was found to be essential for the survival of the tissue. Growth was increasingly better with the increase in inositol content of the medium. A minimum level of inositol was required for organ differentiation. Organ differentiation was also promoted by the increase in inositol concentration in the medium. The chlorophyll content of the tissue increased with the increasing concentration of inositol. Presence of 2-deoxyglucose in the inositol-containing medium led to inositol deficiency symptoms. IN AN EARLIER communication (Kaul and Sabharwal, 1972) we reported establishment of Haworthia tissue cultures on chemically defined media and control of organ differentiation by manipulation of auxin and cytokinin levels in the medium. This paper is a report of our investigations on the effects of inositol on the growth and differentiation of Haworthia tissue cultures. Data on the effects of 2-deoxyglucose in presence of inositol have also been presented. MATERIALS AND METHODS-Tissue used in the present study was derived from inflorescence axes and gynoecia of Haworthia sp. nov. (Sect. Retusae), Kaul and Sabharwal (1972). Stock cultures were maintained on a modified (Kasperbauer and Reinert, 1965) Murashige and Skoog's medium (MS medium) supplemented with 0.2 mg/liter indole-3-acetic acid (IAA) and 0.2 mg/liter a-napthaleneacetic acid (NAA). Approximately 20 mg (dry weight) tissue was inoculated per culture. Experimental media contained the components of MS medium or those of Boll and Street's (1951) modification of White's medium (WB medium).