Tobacco Stem Segments Research Articles

Regulatory dephosphorylation of CDK at G₂/M in plants: yeast mitotic phosphatase cdc25 induces cytokinin-like effects in transgenic tobacco morphogenesis.

During the last three decades, the cell cycle and its control by cyclin-dependent kinases (CDKs) have been extensively studied in eukaryotes. This endeavour has produced an overall picture that basic mechanisms seem to be largely conserved among all eukaryotes. The intricate regulation of CDK activities includes, among others, CDK activation by CDC25 phosphatase at G₂/M. In plants, however, studies of this regulation have lagged behind as a plant Cdc25 homologue or other unrelated phosphatase active at G₂/M have not yet been identified. Failure to identify a plant mitotic CDK activatory phosphatase led to characterization of the effects of alien cdc25 gene expression in plants. Tobacco, expressing the Schizosaccharomyces pombe mitotic activator gene, Spcdc25, exhibited morphological, developmental and biochemical changes when compared with wild type (WT) and, importantly, increased CDK dephosphorylation at G₂/M. Besides changes in leaf shape, internode length and root development, in day-neutral tobacco there was dramatically earlier onset of flowering with a disturbed acropetal floral capacity gradient typical of WT. In vitro, de novo organ formation revealed substantially earlier and more abundant formation of shoot primordia on Spcdc25 tobacco stem segments grown on shoot-inducing media when compared with WT. Moreover, in contrast to WT, stem segments from transgenic plants formed shoots even without application of exogenous growth regulator. Spcdc25-expressing BY-2 cells exhibited a reduced mitotic cell size due to a shortening of the G₂ phase together with high activity of cyclin-dependent kinase, NtCDKB1, in early S-phase, S/G₂ and early M-phase. Spcdc25-expressing tobacco ('Samsun') cell suspension cultures showed a clustered, more circular, cell phenotype compared with chains of elongated WT cells, and increased content of starch and soluble sugars. Taken together, Spcdc25 expression had cytokinin-like effects on the characteristics studied, although determination of endogenous cytokinin levels revealed a dramatic decrease in Spcdc25 transgenics. The data gained using the plants expressing yeast mitotic activator, Spcdc25, clearly argue for the existence and importance of activatory dephosphorylation at G₂/M transition and its interaction with cytokinin signalling in plants. The observed cytokinin-like effects of Spcdc25 expression are consistent with the concept of interaction between cell cycle regulators and phytohormones during plant development. The G₂/M control of the plant cell cycle, however, remains an elusive issue as doubts persist about the mode of activatory dephosphorylation, which in other eukaryotes is provided by Cdc25 phosphatase serving as a final all-or-nothing mitosis regulator.

Accumulation of xylem transported protein at pit membranes and associated reductions in hydraulic conductance

Proteins and traces of polysaccharide are the only polymeric colloids consistently transported in the xylem sap of plants. The hypothesis that such proteins could have physical inhibitory effects on xylem water transport was investigated. Ovalbumin, with a molecular weight of 45 kDa and a molecular diameter of 5.4 nm, is an inert, water-soluble protein that is midway along the size range of endogenous xylem sap proteins. Solutions of ovalbumin conjugated to a fluorescent marker and supplied to transpiring shoot explants of tobacco (Nicotiana tabacum L.) and olive (Olea europaea L.) were shown by confocal laser scanning microscopy to accumulate specifically at wall-based pit membranes that connect neighbouring xylem conduits. In addition, pressure-induced perfusion of micro-filtered ovalbumin solutions, at concentrations similar to those of endogenous xylem sap proteins, through the xylem of tobacco stem or olive twig segments resulted in the retention of c. 40% of the ovalbumin and reductions in the axial hydraulic conductance of the xylem. Smaller molecules such as Texas Red 3000 (MW 3 kDa) and Alexafluor 488–cadaverin conjugates (MW 0.64 kDa) did not show similar characteristics. The partial reduction in xylem hydraulic conductance appeared to be related to the accumulation of ovalbumin at xylem pit membranes and the consequent fouling of trans-membrane water-conducting pores with smaller diameters than those of the ovalbumin molecules. Potential implications of these novel findings for whole-plant water relations are considered.

Expression of the fission yeast cell cycle regulator cdc25 induces de novo shoot formation in tobacco: evidence of a cytokinin-like effect by this mitotic activator

During the last decade, the cell cycle and its control by cyclin-dependent kinases (CDKs) has been extensively studied in eukaryotes. The regulation of CDK activity includes, among others, its activation by Cdc25 phosphatase at G 2/M. However, within the plant kingdom studies of this regulation have lagged behind and a plant cdc25 homologue has not been identified yet. Here, we report on the effects of transformation of tobacco ( Nicotiana tabacum L., cv. Samsun) with fission yeast ( Schizosaccharomyces pombe) cdc25 ( Spcdc25) on de novo plant organ formation, a process dependent on rate and orientation of cell division. On shoot-inducing medium (low 1-naphthylacetic acid (NAA), high 6-benzylaminopurine (BAP)) the number of shoots formed on internode segments cultured from transgenic plants was substantially higher than in the non-transformed controls. Anatomical observations indicated that the shoot formation process was accelerated but with no changes in the quality and sequence of shoot development. Surprisingly, and in contrast to the controls, when on root-inducing medium (high NAA, low BAP) cultured segments from transgenic plants failed to initiate hardly any roots. Instead, they continued to form shoots at low frequencies. Moreover, in marked contrast to the controls, stem segments from transgenic plants were able to form shoots even without the addition of exogenous growth regulators to the medium. The results indicate that Spcdc25 expression in cultured tobacco stem segments mimicked the developmental effects caused by an exogenous hormone balance shifted towards cytokinins. The observed cytokinin-like effects of Spcdc25 transformation are consistent with the concept of an interaction between cell cycle regulators and phytohormones during plant development.

Regeneration of intact tobacco plants containing full length copies of genetically engineered T-DNA, and transmission of T-DNA to R1 progeny

Cloned DNA sequences encoding yeast alcohol dehydrogenase and a bacterial neomycin phosphotransferase have been inserted into the T-DNA of Agrobacterium tumefaciens plasmid pTiT37 at the "rooty" locus. Transformation of tobacco stem segments with the engineered bacterial strains produced attenuated crown gall tumors that were capable of regeneration into intact, normal tobacco plants. The yeast gene and entire transferred DNA (T-DNA) were present in the regenerated plants in multiple copies, and nopaline was found in all tissues. The plants were fertile, and seedlings resulting from self-pollination also contained intact and multiple copies of the engineered T-DNA. Expression of nopaline in the germinated seedlings derived from one regenerated plant was variable and did not correlate with the levels of T-DNA present in the seedlings. Preliminary evidence indicates that nopaline in progeny of other similarly engineered plants is more uniform. The disarming of pTiT37 by insertions at the "rooty" locus thus appears to produce a useful gene vector for higher plants.

The effects of Z(3-phenyl-1,2,4,4-thiadiazol-5-yl)thio] acetic acid, a synthetic growth regulator, on auxin uptake by tobacco stem segments and crown gall suspension culture cells

Z(3-phenyl-1,2,4-thiadiazol-5-yl)thio] Acetic acid (PTAA) is a novel synthetic plant growth regulator causing disturbance of trophic responses and increased branching in one-year-old apple trees and a variety of other species. Its effects are similar to those of 2,3,5-triiodobenzoic acid (TIBA), an inhibitor of popular auxin transport. Auxin uptake by both tobacco stem segments and Parthenocissus tricuspidata crown gall tissue culture cells is stimulated 2–3 fold by both PTAA and TIBA, probably as a result of inhibition of a component of auxin efflux from the cells. The optimum concentration of PTAA is 0.5–10 μ mol/l at pH 4.5 and 10–100 μ mol/l at pH 6.5 for the crown gall cells and about 10 μ mol/l at Ph 6.0 for tobacco stem tissue. It is suggested that PTAA may be an inhibitor of polar auxin transport. Such inhibition may partly account for its growth-modifying properties.

Rapid Initiation of Thymidine Incorporation into Deoxyribonucleic Acid in Vegetative Tobacco Stem Segments Treated with Indole-3-acetic Acid

The short term effect of 11.4 mum indoleacetic acid on the incorporation of (methyl-(3)H)thymidine into DNA in vegetative tobacco (Nicotiana tabacum cv. Wis. 38) stem segments has been investigated. In segments that are defoliated, inverted, and kept in the dark for 7 hours, indoleacetic acid very rapidly (about 60 minutes) and strikingly initiates thymidine incorporation into DNA. The time required before enough indoleacetic acid (2.8 mum) to enhance thymidine incorporation moves into a segment has been found to be about 35 minutes. The initiation response time for segment tissue that already contains 2.8 mum indoleacetic acid should be no more than about 25 minutes. The rate of labeled thymidine incorporation into DNA is affected by physiological treatments of segments. Moving segments from the light into the dark or defoliating segments or inverting defoliated segments decreases the rate of thymidine incorporation. For segments given all three treatments, indoleacetic acid restores the rate of thymidine incorporation as compared to controls. Darkness, or defoliation or inversion of segments, therefore, may decrease thymidine incorporation into DNA by effecting reduced auxin levels in stem segments.

Attempts to induce tumours with nucleic acid preparations from Agrobacterium tumefaciens.

Nucleic acid preparations from Agrobacterium tumefaciens (Smith & Townsend) Conn. have been tested for tumorigenic activity on a number of bioassay systems including carrot root explants, sunflower and tobacco stem segments, callus cultures of sunflower, tobacco and carrot, and sunflower stems. The methods used to isolate and test the DNA included those which have been reported to be successful for the induction of tumours. Strict precautions were taken to ensure that the DNA samples used in the tests were free of viable bacterial cells. In the large number of tests carried out under various experimental conditions there was no evidence for the induction of tumours with bacterial DNA.

Flower Formation in Excised Tobacco Stem Segments

A method has been developed that extracts DNA from stem tissue of flowering tobacco plants, Nicotiana tabacum cv. Wis. 38. The DNA content of stem tissue from a flowering tobacco plant is correlated with its capacity to flower in vitro. Stem segments known to form 100% floral buds contain 10 times more DNA per gram fresh weight than segments that form 5% floral buds and 95% vegetative buds, and in the uppermost 28 centimeters of flowering tobacco plant stems the DNA content decreases roughly in parallel with the floral gradient.((3)H)-Thymidine incorporation into DNA in the internodes is inhibited by attached leaves in flowering tobacco plants but promoted in vegetative plants. Low indoleacetic acid concentrations (2.8 and 5.7 mum) inhibit DNA synthesis in internodes of defoliated stems of flowering tobacco plants to the same extent as attached leaves, whereas the same concentrations of indoleacetic acid promote DNA synthesis in internodes of defoliated stems of vegetative plants. The optimal concentration (11.4 mum) of indoleacetic acid supplied to defoliated stems of vegetative plants increased the rate of DNA synthesis to 4 times the rate in defoliated stems without indoleacetic acid treatment. This increase more than compensates for the promotion of DNA synthesis by the young leaves. Thus, the opposite effects of young leaves on DNA synthesis in internodes of flowering and vegetative tobacco plants may be related to their auxin content.

Flower Formation in Excised Tobacco Stem Segments; I. Methodology and Effects of Plant Hormones

The formation of flowers has been studied in stem tissue excised from flowering plants of Nicotiana tabacum variety Wisconsin No. 38, and cultured in vitro on Murashige and Skoog nutrient medium. A procedure for quantitative evaluation of factors influencing floral expression has been developed and effects of the growth substances, indole-3-acetic acid (IAA), kinetin and gibberellic acid (GA(3)), on the process are reported.Although a low (1 mum) level of IAA was required for the development of normal flowers on stem segments, higher concentrations tended to inhibit flowering. The decrease in floral buds was rapid in the 3 to 15 mum range. IAA concentrations up to 75 mum increased vegetative bud formation so as to effect a transition from floral to vegetative buds rather than merely an inhibition of bud formation. Higher IAA concentrations inhibited both vegetative and floral bud formation.Kinetin in high concentrations greatly increased the number of vegetative buds but had no significant effect on the number of floral buds per segment. High kinetin concentrations also permitted branching of floral shoots so that flower clusters were formed.GA(3) applied in the medium from the start, strongly inhibited bud formation on the stem segments, but when applied to young floral buds after they had formed, it promoted their further development ("bolting").Flower formation occurred in complete darkness, but light of moderate intensity was required for the development of normal flowers.

Flower Formation in Excised Tobacco Stem Segments; II. Reversible Removal of IAA Inhibition by RNA Base Analogues

The RNA base analogues, 2-thiouracil, 6-azauracil and 8-azaguanine incorporated singly into the medium, increased the number of floral buds in excised stem segments of Nicotiana tabacum variety Wisconsin No. 38 cultured in vitro. Combined treatments with 2 and 3 base analogues were even more effective. The effects were prevented by the corresponding natural counterparts, uracil, uridine, and guanosine respectively. These nucleic acid constituents added to cultures without base analogues did not affect the number of floral buds formed. In stem segments from the lower internodes treatments with the analogues effected a transition from vegetative to floral bud formation, thus in a sense removing the floral gradient as defined by Chouard and Aghion.The inhibition of flower bud formation ordinarily achieved even with low concentrations of indole-3-acetic acid (IAA) was counteracted by low concentrations of 2-thiouracil, 6-azauracil and 8-azaguanine. Reversal to vegetative bud formation was not achieved even with high IAA concentrations in the presence of the base analogues.Stem segments excised from young, vegetative tobacco plants never formed floral buds in vitro. Thus, the inhibiting effect of IAA and the promoting effect of base analogues seem to be on the expression and not on the induction of flowering. The regulatory action of the IAA and base analogues in flower bud formation is tentatively ascribed to their differential effects on RNA synthesis.

Auxin Activity of Substituted Benzoic Acids and Their Effect on Polar Auxin Transport

Six dichloro-, 3 trichloro-, 2 triiodo-, and 3 heterosubstituted benzoic acids (amiben, dinoben, dicamba), and N-1-naphthylphthalamic acid have been tested for effects on growth and on polar auxin transport. Growth activity with and without kinetin was measured by effects on fresh and dry weights of 30-day cultures of fresh tobacco pith. Transport inhibition was measured by following uptake and output of IAA-2-(14)C through 10 mm bean epicotyl sections. The distribution of callus growth on vascularized tobacco stem segments was also observed. Avena first internode extension assays established the relative activities: dicamba > amiben > dinoben suggested by pith growth results. Growth effects of active compounds were similar with and without kinetin, except that amiben was less active with kinetin, while 2,3,6-trichlorobenzoic acid was more active with kinetin than alone. The weak auxin activity of NPA was confirmed. Transport experiments showed that NPA was the most inhibitory compound tested, followed by TIBA. Other compounds tested were at least 300 times less inhibitory to IAA transport. The best growth promoters were the least inhibitory to transport, and the most effective transport inhibitors were at best poor auxins. It is suggested that the weak auxin and auxin synergistic activity of TIBA (and perhaps 2,3-dichlorobenzoic acid) in extension growth tests arises from its inhibition of transport of endogenous or added auxin out of the sections, rather than from its intrinsic auxin activity. Chemically induced apolar callus growth on vascularized tobacco stem explants can arise from inhibition of native auxin transport, apolar growth stimulation by auxinic action of the test compound, or both.

The Role of Auxins in Root‐Knot Nematode‐Induced Growth on Excised Tobacco Stem Segments

AbstractRoot‐knot nematodes, Meloidogyne incognita, induced lumps of callus tissue on the cambial surfaces of peeled tobacco stem segments cultured in vitro. Except for a layer 1 to 3 cells thick, callus was limited to the basal ends of control segments. Indole‐3‐acetic acid (IAA) applied in agar blocks to the centers of stem segments, when it had any effect on the cambial surface, induced streaks of callus extending from the blocks toward the basal ends of the segments. IAA in agar blocks also increased callus growth at the basal ends of the segments, increased the growth of pith on the undersides of the segments, promoted root initiation, but inhibited bud initiation. Nematodes produced none of these effects, nor did they change the type of organs induced by various concentrations of IAA in the medium. Callus tissue did grow on the cambial surface of stem segments surrounding agar blocks containing 2,3,5‐triiodobenzoic acid, an inhibitor of polar auxin transport.Paraffin sections showed that the nematodes were confined to the callus tissue on the cambial surfaces of the segments. Except for occasional syncytia and areas of cell division, nematode‐induced callus was composed of thin‐walled, irregularly shaped cells arising from the cambium.Differences between the responses of tobacco stem segments to root‐knot nematodes and IAA‐agar blocks indicate that auxins were not freed from the plant tissue nor secreted by the nematodes. Instead, it is suggested that nematodes enabled the tissue to retain and use endogenous auxins that otherwise would have been transported to the basal ends of the segments.

The Effect of Certain Benzazole Compounds on Plant Growth and Development

Klingensmith, M. J. (Colgate U., Hamilton, N. Y.) The effect of certain benzazole compounds on plant growth and development. Amer. Jour. Bot. 48(1): 40–45. Illus. 1961.—A number of benzazoles, in particular benzimidazole, benzothiazole, and benzotriazole, were examined for their effects on growth of seedlings and established plants. Benzothiazole was the most active in repressing elongation of the primary root of cucumber. Benzimidazole and benzotriazole were about 1/10 as active. Adenine was without effect in reversing the benzazole-induced inhibition of cucumber root elongation and, in fact, supplemented the inhibition caused by benzimidazole and benzothiazole. Application of benzotriazole to the root medium of bean, coleus, tomato, oat and wheat caused a pronounced inhibition of internodal elongation with a stimulation of axillary development. Distinct morphological changes were observed which did not correspond to those produced by other growth regulators. Application of benzimidazole to the root medium of several genera of plants resulted in injury to laminar tissue followed by desiccation, with no concomitant effect on the stem. Application of benzothiazole to the root medium induced development of adventitious roots in bean and tomato. This compound also caused initiation of roots on cultures of tobacco-stem segments, while not suppressing bud development. The benzazoles tested seem to be of a different class of compounds from other growth regulators which have been studied. The responses elicited by treatment with each of the 3 benzazoles are distinctly characteristic and are dependent on the structure of the azole portion of the molecule.

KINETIN‐INDUCED PSEUDONODULES ON TOBACCO ROOTS

Arora, Nirmal, F. Skoog, and O. N. Allen. (U. Wisconsin, Madison.) Kinetin‐induced pseudonodules on tobacco roots. Amer. Jour. Bot. 46(8): 610–613. Illus. 1959.—Tobacco stem segments were cultured on modified White's medium containing 0.02–0.1 mg./l. of kinetin, 2 mg./l. of IAA and 2 g./l. of casein hydrolysate. Roots grew profusely from these stem pieces. In the presence of kinetin, especially when a second supply (0.2 mg./l.) was introduced after the roots had developed, large numbers of pseudonodules were formed along the root surfaces. The protuberances were spherical in shape and were invariably associated with the axial area of lateral rootlets derived as root primordia from parent root pericycle. Development of the pseudonodules started with the division and enlargement of cortical cells. The center of each pseudonodule contained either a simple provascular strand constituting a modified rootlet with a poorly defined apex and layers of tracheids at the base, or a normal lateral root primordium capable of continued growth and eventual emergence as a rootlet. In later stages, the swellings became lobed and the mature cells showed a high starch content. Although these kinetin‐induced pseudonodules arose from cortical tissue, their anatomical structure remained undifferentiated and unspecialized and bore no resemblance to that of typical nodules caused by rhizobia.

Chemical Control of Bud Formation in Tobacco Stem Segments

American Journal of BotanyVolume 40, Issue 10 p. 768-773 Article CHEMICAL CONTROL OF BUD FORMATION IN TOBACCO STEM SEGMENTS Carlos Miller, Carlos Miller Department of Botany, University of Wisconsin, Madison 6, WisconsinSearch for more papers by this authorFolke Skoog, Folke Skoog Department of Botany, University of Wisconsin, Madison 6, WisconsinSearch for more papers by this author Carlos Miller, Carlos Miller Department of Botany, University of Wisconsin, Madison 6, WisconsinSearch for more papers by this authorFolke Skoog, Folke Skoog Department of Botany, University of Wisconsin, Madison 6, WisconsinSearch for more papers by this author First published: 01 December 1953 https://doi.org/10.1002/j.1537-2197.1953.tb06553.xCitations: 51AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat Citing Literature Volume40, Issue10December 1953Pages 768-773 RelatedInformation

Reversible inhibition of cell division and enlargement in plant tissues by 2,6-diaminopurine.

Summary1. 2,6-diaminopurine has been shown to inhibit cell division in tobacco stem callus and habituated tobacco callus cultures, to prevent the formation of buds in tobacco stem pieces cultured in vitro, to reduce cell enlargement in tobacco pith pieces cultured in vitro, and to inhibit elongation of etiolated pea stem and Avena coleoptile segments floated on test solutions. 2. Adenine, arginine, guanine, hypoxanthine, and xanthine were tested in attempts to reverse the inhibition by diaminopurine of callus growth and bud formation in tobacco stem segments. Adenine was very effective and slight reversal was obtained with guanine and hypoxanthine. 3. Reversal of the DAP inhibition of tobacco pith cell enlargement was obtained with adenine and guanine, but adenine was more effective. No other compounds were tested on this tissue. 4. Reversal of the diaminopurine inhibition of etiolated pea stem segment elongation was attempted only with adenine, adenosine, and adenylic acid. All three compounds gave parti...

ORIGIN OF BUDS IN TOBACCO STEM SEGMENTS CULTURED IN VITRO

DESPITE THE great wealth of botanical literature concerned with the initiation of adventitious buds (Priestley and Swingle, 1929; Buvat, 1944-45; Peeters, 1947), there have been relatively few anatomical studies on bud initiation in tissues cultured in synthetic media. Buvat (1944-45) has summarized these and has, himself, added considerably to an understanding of the problem of dedifferentiation2 of plant cells. However, his investigations concern principally the cytological aspects of primordium formation. Although Camus (1949) has studied the changes in subjacent tissues during bud development, he has not considered the details of initiation of the shoot primordia. Previous communications (Skoog, 1944; Skoog and Tsui, 1948, 1951; Sterling, 1950) have shown a marked correlation between relatively high levels of adenine, supplied through a culture medium, and bud initiation in tobacco stem segments. Obviously, the establishment of such a relationship makes possible the chemical control of bud formation. It is, therefore, of interest to place on record the successive steps in this controlled initiation of shoot primordia in vitro. This paper presents an anatomical description of such development and considers the latter in relation to the general problems of meristematic activity and dedifferentiation. MATERIALS AND METHODS.-The materials and methods used are those reported earlier (Sterling, 1950), with the limitation that this account deals only with the tobacco stem segments which received adenine sulfate (40 mg./l.) in the basal medium. The material is representative of the samples used in physiological studies on growth and tissue composition. Segments grown on control media were described in the earlier paper. SITES OF BUD ORIGIN.-In these cultures, there are three maj or regions of bud formation, Viz., cambium-external phloem, internal phloem, and callus. The region of the cambium and its young phloic derivatives produces the maj ority of bud primordia. In most instances, no sharp distinction can be made between these two classes of cells in the rapidly dividing cambial zone; therefore, this source of buds was previously reported as cambial (Sterling, 1950). However, in some cases bud primordia are found exclusively in the external phloem, with differentiated sieve tubes lying be-

Origin of Buds in Tobacco Stem Segments Cultured in Vitro

American Journal of BotanyVolume 38, Issue 10 p. 761-767 Article ORIGIN OF BUDS IN TOBACCO STEM SEGMENTS CULTURED IN VITRO Clarence Sterling, Clarence Sterling Division of Food Technology, University of California, Berkeley, CaliforniaSearch for more papers by this author Clarence Sterling, Clarence Sterling Division of Food Technology, University of California, Berkeley, CaliforniaSearch for more papers by this author First published: 01 December 1951 https://doi.org/10.1002/j.1537-2197.1951.tb14889.xCitations: 14AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat Citing Literature Volume38, Issue10December 1951Pages 761-767 RelatedInformation

Histogenesis in Tobacco Stem Segments Cultured In vitro

American Journal of BotanyVolume 37, Issue 6 p. 464-470 Article HISTOGENESIS IN TOBACCO STEM SEGMENTS CULTURED IN VITRO Clarence Sterling, Clarence Sterling 3411 W. 15th St., Los Angeles 6, CaliforniaSearch for more papers by this author Clarence Sterling, Clarence Sterling 3411 W. 15th St., Los Angeles 6, CaliforniaSearch for more papers by this author First published: 01 June 1950 https://doi.org/10.1002/j.1537-2197.1950.tb08196.xCitations: 10AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat Citing Literature Volume37, Issue6June 1950Pages 464-470 RelatedInformation

The Growth of Normal Plant Tissue in Vitro as Affected by Chemical Carcinogens and Plant Growth Substances. III. The Culture of Sunflower and Tobacco Stem Segments

The Growth of Normal Plant Tissue in Vitro as Affected by Chemical Carcinogens and Plant Growth Substances. III. The Culture of Sunflower and Tobacco Stem Segments