Ontogenesis ofin vitro shoot bud proliferation inSolanum sarrachoides Sendt.
01 Aug 1989-Vol. 99, Iss: 4, pp 307-312
TL;DR: In vitro direct induction of multiple shoot buds of Solanum sarrachoides Sendt.
Abstract: In vitro direct induction of multiple shoot buds ofSolanum sarrachoides Sendt. was obtained from leaf segments using Murashige and Skoog’s basal medium supplemented with 6-γ-γ-(dimethylallylamino) purine (1·5–2·5 mgl−1). Maximum shoot bud proliferation was observed in the medium containing 2 mgl−1 and better growth of plants with well defined roots, leaves, flowers and fruits in the subsequent stages of development. Histological examination at different stages of development confirmed that the multiple buds produced on excised leaf segments arise adventitiously through the formation of numerous tiny protuberances. The complete sequence of events leading to multiple bud formation based on histological studies has been presented.
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TL;DR: In vivo redox biosensing resolves the spatiotemporal dynamics of compartmental responses to local ROS generation and provide a basis for understanding how compartment-specific redox dynamics may operate in retrograde signaling and stress 67 acclimation in plants.
Abstract: In experiments with tobacco tissue cultured on White's modified medium (basal meditmi hi Tnhles 1 and 2) supplemenk'd with kiticthi and hidoleacctic acid, a slrikin^' fourlo (ive-told intTease iu yield was ohtaitu-d within a three to Tour week j^rowth period on addition of an aqtteotis exlrarl of tobacco leaves (Fi^'ures 1 and 2). Subse(iueutly it was found Ihiit this jnoniotiou oi' f^rowih was due mainly though nol entirely to inorj^auic rather than organic con.stitttenls in the extract. In the isolation of Rrowth factors from plant tissues and other sources inorj '̂anic salts are fre(|uently carried along with fhe organic fraclioits. When tissue cultures are used for bioassays, therefore, il is necessary lo lake into account increases in growth which may result from nutrient elements or other known constituents of the medium which may he present in the te.st materials. To minimize interference trom rontaminaitis of this type, an altempt has heen made to de\\eh)p a nieditmi with such adequate supplies of all re(iuired tnineral nutrients and cotntnott orgattic cottslitueitls that no apprecial»le change in growth rate or yield will result from the inlroduclion of additional amounts in the range ordinarily expected to be present in tnaterials to be assayed. As a point of referetice for this work some of the culture media in mc)st common current use will he cotisidered briefly. For ease of comparis4)n Iheir mineral compositions are listed in Tables 1 and 2. White's nutrient .solution, designed originally for excised root cultures, was based on Uspeuski and Uspetiskaia's medium for algae and Trelease and Trelease's micronutrieni solution. This medium also was employed successfully in the original cttltivation of callus from the tobacco Iiybrid Nicotiana gtauca x A', tanijadorffii, atitl as further modified by White in 194̂ ^ and by others it has been used for the
63,098 citations
TL;DR: A comparative histochemical study of changes in nucleic acids, proteins, and carbohydrates was performed on freeze-substituted samples of tobacco callus, cultured under shoot-forming and non-organ-...
Abstract: A comparative histochemical study of changes in nucleic acids, proteins, and carbohydrates was performed on freeze-substituted samples of tobacco callus, cultured under shoot-forming and non-organ-...
154 citations
TL;DR: An ultrastructural investigation of shoot initiation in tobacco callus cultures was made and zones of preferential division were observed in the basal portion of the tissue by eight days in culture and these led, sequentially, to meristemoids, primordia, and shoots.
Abstract: An ultrastructural investigation of shoot initiation in tobacco (Nicotiana tabacum L. var. W. 38) callus cultures was made. Zones of preferential division were observed in the basal portion of the tissue by eight days in culture and these led, sequentially, to meristemoids, primordia, and shoots. During the initial stages of meristemoid formation, protein inclusions and large accumulations of plastid starch were present in the cells, while vacuoles were filled with membranous and cytoplasmic protrusions. At later stages of meristemoid development, these features were not observed in the cells, which were also smaller in size and possessed numerous small, peripheral vacuoles. It appears that the membranous and cytoplasmic protrusions are involved in vacuolar reduction during meristemoid formation. It would also appear that the storage materials supply the energy and other reserves needed for the organogenetic process. By contrast, tissue cultured under nonshoot-forming conditions and nonmeristemoid regions of shoot-forming tissue remained parenchymatous over the same time period. ZONES OF preferential cell division occur in the parenchymatous tissue of callus cultures of tobacco by day 8 (Thorpe and Murashige, 1970). Meristemoids arise from these areas, although not all areas of preferential cell division give rise to these structures. Meristemoids (Torrey, 1966) are the meristem-like aggregations of small, nonpolar cells which appear to be nonvacuolate at the light microscope level and from which primordia and ultimately leafy vegetative shoots are formed (Murashige, 1964; Thorpe and Murashige, 1970). The mechanism of meristemoid formation in tissue cultured under organ-forming conditions is not yet known, although it has been suggested that these could arise from single cells (Torrey, 1966). Associated with meristemoid development is a rapid increase and decrease in the amount of stored starch in tobacco callus (Thorpe and Murashige, 1968, 1970). This starch may serve as a source of energy for shoot formation which, judging by the respiratory activity of the tissue (Thorpe and Meier, 1972; Ross and Thorpe, 1973), has a high energy requirement. In this study, ultrastructural changes during meristemoid formation and shoot initiation were investigated. MATERIALS AND METHODS-Tobacco (Nicotiana tabacum L. var. 'Wisconsin 38') callus was isolated from stem pith segments and maintained on three-quarter strength Murashige-Skoog (MS) 1 Received for publication 27 November 1972. Supported by NRC of Canada grant no. A-6467 to T.A.T. medium (Murashige and Skoog, 1962). For shoot production, the tissue was grown on the modified MS medium reported earlier (Thorpe and Murashige, 1970) except that the concentrations of Ltyrosine, adenine sulphate, and NaH2PO4 H20 were reduced by half. The medium contained indole-3-acetic acid and kinetin in final concentrations of 10-5M. Cultures were maintained in darkness in 125-ml Erlenmeyer culture vessels containing 50 ml of medium. Sections of tobacco callus, each measuring ca. 3 x 3 x 2 mm, were used as inoculum. Thin sections, cut by hand, parallel to the surface in contact with the medium were irrigated with fixative (2/2 % glutaraldehyde) and scanned under a binocular microscope. Areas of preferential division, with prominent nuclei, and areas of shoot initiation were excised and prepared for electron microscopy. Each piece of tissue was ca. 1 mm3. Tissue was sampled from 8-, 10-, 12-, and 14-day-old shoot-forming tissue and from 8-, and 14-day-old nonshoot-forming tissue. Freehand monitor sections were also stained with iodinepotassium iodide (Jensen, 1962). Heavy blueblack staining for starch occurred in the regions visually determined as areas of preferential cell division or meristemoids (Thorpe and Murashige, 1968). The tissue samples were prefixed in 21?% glutaraldehyde in 0.1 M phosphate buffer, pH 6.8 -+ 0.5 for 4 hr. Following buffer washes, the material was fixed in 1 % unbuffered Os04 for 50 min. The tissue was then dehydrated in an ethanolic series after a further buffer wash and embedded in ERL-4206 (Spurr, 1969). Staining was
74 citations
TL;DR: This chapter reviews the solasodine-bearing plants and finds that using fruits may be advantageous in terms of easier chemical purification, but this can be nullified by rapid loss of solasadine during fruit ripening.
Abstract: Publisher Summary Solasodine, a nitrogen analogue of diosgenin, is gaining importance to the pharmaceutical industry This chapter reviews the solasodine-bearing plants There are nearly one hundred different Solanum species reported to contain solasodine to one degree or another Only a handful of species; however, have been considered for commercial production of solasodine— S aviculare , S khasianum , and S laciniatum are the main candidates Solasodine is found in all parts of poroporo plants Younger leaves and fruits contain most of the solasodine Using fruits may be advantageous in terms of easier chemical purification, but this can be nullified by rapid loss of solasodine during fruit ripening Most of the interest in solasodine-bearing plants is because of their potential conversion of solasodine to synthetic drugs Poropora leaves have been used to make poultices for skin disorders In addition, a solasodine derivative— solaplumbin—claimed to have anticancer activity
66 citations
64 citations