Showing papers on "Kinetin published in 1996"
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TL;DR: Plants can control cell division by tyrosine phosphorylation of Cdc2 but differ from somatic animal cells in coupling this mitotic control to hormonal signals.
Abstract: In excised pith parenchyma from Nicotiana tabacum L. cv. Wisconsin Havana 38, auxin (naphthalene-1-acetic acid) together with cytokinin (6-benzylaminopurine) induced a greater than 40-fold increase in a p34cdc2-like protein, recoverable in the p13suc1-binding fraction, that had high H1 histone kinase activity, but enzyme induced without cytokinin was inactive. In suspension-cultured N. plumbaginifolia Viv., cytokinin (kinetin) was stringently required only in late G2 phase of the cell division cycle (cdc) and cells lacking kinetin arrested in G2 phase with inactive p34cdc2-like H1 histone kinase. Control of the Cdc2 kinase by inhibitory tyrosine phosphorylation was indicated by high phosphotyrosine in the inactive enzyme of arrested pith and suspension cells. Yeast cdc25 phosphatase, which is specific for removal of phosphate from tyrosine at the active site of p34cdc2 enzyme, was expressed in bacteria and caused extensive in-vitro activation of p13suc1-purified enzyme from pith and suspension cells cultured without cytokinin. Cytokinin stimulated the removal of phosphate, activation of the enzyme and rapid synchronous entry into mitosis. Therefore, plants can control cell division by tyrosine phosphorylation of Cdc2 but differ from somatic animal cells in coupling this mitotic control to hormonal signals.
265 citations
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TL;DR: Higher regeneration from hypocotyl and petiole explants was obtained on BA with IBA than on zeatin- or kinetin-supplemented media, and direct adventitious shoot bud induction was recorded highest on MS medium.
Abstract: Techniques for the regeneration of Jatropha curcas L. from various explants have been developed. Regeneration from hypocotyl, petiole and leaf explants was evaluated on a range of concentrations of zeatin, kinetin and N6 benzyladenine (BA) either singly or in combination with indole-3-butyric acid (IBA). Higher regeneration from hypocotyl and petiole explants was obtained on BA with IBA than on zeatin- or kinetin-supplemented media. Leaf discs from the third expanding leaf exhibited higher regeneration potential than those from the fourth leaf. Independent of the explant type, direct adventitious shoot bud induction was recorded highest on MS medium with 2.22 μM BA and 4.9 μM IBA. Although the same BA concentration but with reduced IBA concentration (0.49 μM) proved effective in callus mediated regeneration from hypocotyl and leaf explants, the petioles required lower concentrations of the two growth regulators (0.44 μM BA and 0.49 μM IBA). Regenerated shoots could be rooted on growth regulator-free gelled full-strength MS medium. Following simple hardening procedures, the in vitro-raised plants could be transferred to soil and grown to maturity in the field.
182 citations
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TL;DR: A procedure for rapid in vitro propagation of the aromatic and medicinal plant Hemidesmus indicus (L.) R.Br.
Abstract: A procedure for rapid in vitro propagation of the aromatic and medicinal plant Hemidesmus indicus (L.) R.Br. (Family Asclepiadaceae) from nodal explants is described. The highest shoot multiplication rate of 8.2 ± 0.4 shoots/explant with a 95% frequency was achieved in S weeks culture period on Murashige and Skoog medium supplemented with 1.15 μM kinetin and 0.054 μM α-naphthaleneacetic acid. Excised shoots were rooted on the same basal medium supplemented with 1.15 μM kinetin and 7.35 μM indole-3-butyric acid. Shoots derived from subcultures exhibited better rooting response than those from primary cultures. After a hardening phase of 2 weeks, there was a 70% transplantation success in the field.
89 citations
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TL;DR: To understand the culture characteristics of suspended cells of Panax quinquefolium strain Q91625 in a shake flask, the dynamic changes of various parameters, such as pH, conductivity, wet and dry cell concentrations, and the consumption of major nutrients during cultivation were investigated.
84 citations
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TL;DR: It is discovered that N 6‐furfuryladenine has electrochemical properties that can be applied for monitoring this modified based by a HPLC/UV/EC method and electrochemical assignments by mass‐spectrometric analysis are confirmed.
77 citations
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TL;DR: The growth regulators benzyladenine, kinetin, chlormequat, and daminozide, at concentrations which severely reduced rooting, reduced artemisinin production and was undetected in callus or cell cultures.
Abstract: Artemisinin was produced in differentiated shoot cultures of Artemisia annua L. but was undetected in callus or cell cultures. The growth regulators benzyladenine, kinetin, chlormequat, and daminozide, at concentrations which severely reduced rooting, reduced artemisinin production. A highly significant correlation (1% level) was observed between shoot artemisinin content and number of roots (r=0.775**), but shoot number and artemisinin content were unrelated (r=-0.198). Benzyladenine increased shoot proliferation at 0.5 and 5.0 μM, but decreased root production at 0.5, 5.0, and 50 μM. The highest levels of artemisinin production (0.287% DW) were obtained in hormone-free medium when root production was maximized. Removal of roots from shoots cultured in hormone-free liquid medium reduced shoot artemisinin by 53% and shoot arteannuin B by 60%. Neither artemisinin, arteannuin B, or artemisinic acid were detected from roots developed in semi-solid or liquid medium.
72 citations
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TL;DR: In vitro plant propagation was developed for seedling shoot tips, leaf axils, and cotyledonary nodes of cashew, Anacardium occidentale and the highest frequency of rooted shoots was obtained by treating shoots with the bacterium, Agrobacterium rhizogenes.
Abstract: In vitro plant propagation was developed for seedling shoot tips, leaf axils, and cotyledonary nodes of cashew, Anacardium occidentale. Factors affecting multiplication rate included age of explant source, explant type, medium composition, light requirements, and transfer frequency. Cotyledonary nodes produced more buds than other explant types. Nodes had a 90% viability when transferred daily to fresh medium containing activated charcoal for 7 d while exposed to continuous dark. Cultures were then exposed to low light illumination with weekly transfers. The phytohormone composition producing the most buds was 2.32 μM kinetin, 9.12 μM zeatin and 4.40 μM BA. The highest frequency of rooted shoots was obtained by treating shoots with the bacterium, Agrobacterium rhizogenes. Plants also were recovered by induction of roots using auxin treatment on propagated shoots.
58 citations
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TL;DR: The results of this study confirmed a close link between the polyploidization and the loss of totipotencyin vitro and Tetraploid plants obtained in this study have a potential to be used in interspecific crosses where their tetraploids status could help in overcoming existing breeding barriers due to differences in chromosome number.
Abstract: Embryogenic callus cultures were established from immature cucumber(Cucumis sativus L.) embryos on E20A (Dumas de Vaulxet al. 1981) or MS (Murashige and Skoog 1962) media supplemented with 6-benzylaminopurine (BAP), α-naphthylacetic acid (NAA) and/or 2,4-dichlorophenoxyacetic acid (2,4-D). Regeneration of plants was observed after a transfer to culture media either without growth regulators or supplemented with kinetin and NAA. Flow cytometry was employed to estimate DNA ploidy levels. Most of cell nuclei in young leaf tissues were found in G1 phase with 2C DNA content. Callus cultures were mixoploid with DNA content ranging from 2C to 32C. The frequency of polyploid cells was increasing with the age of culture and the polyploidization was accompanied by a gradual loss of regeneration ability. Plants regenerated from callus cultures were classified as diploid (57 %), tetraploid (18 %), octoploid (4 %) and mixoploid (2n/4n, 4 %) and (4n/8n, 17 %). The results of this study confirmed a close link between the polyploidization and the loss of totipotencyin vitro. Tetraploid plants obtained in this study have a potential to be used in interspecific crosses where their tetraploid status could help in overcoming existing breeding barriers due to differences in chromosome number.
49 citations
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TL;DR: Shooting proliferation from axillary buds of mature field-grown plants was not affected by seasonal fluctuations in the stock plants but depended on the macronutrient composition and on the type and concentration of cytokinin tested.
Abstract: Cultures of Lavandula latifolia Medicus were established from axillary buds of mature field-grown plants. Explants were initially cultured on media with two different macronutrient combinations and benzyladenine or kinetin added either individually or with naphthaleneacetic acid. Subsequently, explants were subcultured in Murashige and Skoog medium supplemented with 20% coconut milk, 0.57 μM indoleacetic acid and 8.88 μM benzyladenine. Shoot proliferation from axillary buds was not affected by seasonal fluctuations in the stock plants but depended on the macronutrient composition and on the type and concentration of cytokinin tested. Best results were obtained in explants initially cultured in media with Murashige and Skoog constituents and supplemented with 5 μM benzyladenine. In vitro-grown shoots were used to induce multiple shooting by transferring them to subculture medium. Shoots were rooted on Murashige and Skoog medium with macronutrients at half-strength. Plantlets were transferred to soil and grown to maturity.
47 citations
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TL;DR: Callus induction, somatic embryogenesis and plant regeneration were obtained in two cultivars of Sorghum bicolor (L.) Moench and the importance of kinetin and dicamba on the induction of embryogenic potential is reported.
Abstract: Callus induction, somatic embryogenesis and plant regeneration were obtained in two cultivars of Sorghum bicolor (L.) Moench. Transverse thin cell layers from roots/epicotyls of 15-day-old seedlings or of regenerated plantlets were used. Callus response depended on the genotype, the size of transverse thin cell layers, the level at which transverse thin cell layers were excised on the epicotyl, the composition of growth substances and the number of in vitro regeneration cycles undergone by the donor plant. Somatic embryos were differentiated under a defined dark/light sequence, from epidermised compact calluses (i.e having already differentiated an epidermis), obtained directly with dicamba or from friable callus initiated with kinetin and 2,4 dichlorophenoxyacetic acid. The importance of kinetin and dicamba on the induction of embryogenic potential is reported.
44 citations
01 Jan 1996
TL;DR: Observation of the roots during phytohormone treatment by 31 P NMR showed that the cytoplasmic pH remained stable, indicating that the perturbation of nitrogen metabolism in the de-differentiated roots must be due to other causes.
Abstract: Primary nitrogen metabolism in transformed root cultures of Datura stramonium was observed by in vivo 15N NMR. Treatment of the root cultures with the plant growth regulators cc-naphthaleneacetic acid (NAA) and kinetin caused a de-differentiation of the root tissue, together with perturbation of primary and secondary nitrogen metabolism. The levels of newly-synthesized glutamine and glutamate during ammonium assimilation were depleted relative to control cultures, whereas GABA biosynthesis was enhanced. Although GABA production could be stimulated by a decrease in cytoplasmic pH (whether imposed artificially or induced by hypoxia), observation of the roots during phytohormone treatment by 31P NMR showed that the cytoplasmic pH remained stable, indicating that the perturbation of nitrogen metabolism in the de-differentiated roots must be due to other causes.
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TL;DR: Plant regeneration through direct somatic embryogenesis of leaf blade explants from in vitro propagated plants of Agave victoria-reginae Moore, is described.
Abstract: Plant regeneration through direct somatic embryogenesis of leaf blade explants from in vitro propagated plants of Agave victoria-reginae Moore, is described. Somatic embryogenesis was evident in a 6-week period on agarsolidified MS medium supplemented with L2 vitamins and 2,4-dichlorophenoxyacetic acid (1,4 µM), and germination of somatic embryos was achieved after 8 weeks on half-strength MS medium and 4 weeks on half-strength SH medium, both lacking growth regulators. Hyperhydricity of somatic embryos and plantlets was reduced by the use of vented culture vessel lids during the last 4 weeks on SH medium. Shoot proliferation was obtained, and hyperhydricity was eliminated on a modified MS medium (with NH4NO3 reduced to 5 mN) supplemented with kinetin (4.6 µM) and 1-naphthaleneacetic acid (1.6 µM) and the use of vented culture vessel lids.
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TL;DR: In this article, α-naphthaleneacetic acid (NAA) and kinetin were applied to root cultures of Datura stramonium to de-differentiate the root tissue and perturb primary and secondary nitrogen metabolism.
Abstract: Primary nitrogen metabolism in transformed root cultures of Datura stramonium was observed by in vivo 15 N NMR. Treatment of the root cultures with the plant growth regulators α-naphthaleneacetic acid (NAA) and kinetin caused a de-differentiation of the root tissue, together with perturbation of primary and secondary nitrogen metabolism. The levels of newly-synthesized glutamine and glutamate during ammonium assimilation were depleted relative to control cultures, whereas GABA biosynthesis was enhanced. Although GABA production could be stimulated by a decrease in cytoplasmic pH (whether imposed artificially or induced by hypoxia), observation of the roots during phytohormone treatment by 31 P NMR showed that the cytoplasmic pH remained stable, indicating that the perturbation of nitrogen metabolism in the de-differentiated roots must be due to other causes.
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TL;DR: The highest increase in tuber size was obtained in agar cultures flushed twice with liquid tuber induction medium, and the potential of bioreactor cultures for potato bud proliferation and enhanced tuber development in double layer agar-liquid cultures is discussed.
Abstract: Single node stem segments fromin vitro potato shoots cultured in liquid medium in the presence of ancymidol (23.4 μM) developed into bud clusters in either shaken flasks or bioreactor cultures. Buds on the clusters developed tubers after subculture to a tuber induction medium with 23.2 μM kinetin, 19.5 μM ancymidol, and 6-8% sucrose. The number of tubers per cluster and their size were higher in agar induction medium on top of which a second layer of liquid medium was added, than in liquid shake or bioreactor cultures. The highest increase in tuber size (i.e., 720 mg fresh weight after 7 weeks), was obtained in agar cultures flushed twice with liquid tuber induction medium. The potential of bioreactor cultures for potato bud proliferation and enhanced tuber development in double layer agar-liquid cultures is discussed.
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TL;DR: The frequency of shoot formation in the BA or kinetin and NAA or IAA combinations indicated that any of the combinations tested can be used for multiplication ofC.
Abstract: Currently,Cereus peruvianus plants can be rapidly clonedin vitro via adventitious organogenesis using callus cultures; however, somaclonal variation is a problem. A method is described herein using lateral bud explants to produce multiple shoots for clonal propagation. Apical and lateral explants were cultured on MS (Murashige and Skoog, 1962) media with factorial combinations of the auxins indole-3-acetic acid (IAA), 1-naphthaleneacetic acid (NAA), and cytokinins 6-ben-zyladenine (BA) and N-(2-furanyl-methyl)-1-purine-6 amine (kinetin) at the concentrations 0.0, 0.01, 0.1, 1.0 mg“l−1. Positive results were obtained from the lateral explants in all conditions tested, but apical explants did not respond toin vitro multiplication ofC. peruvianus cactus at all growth regulator combinations tested. Formation of axillary shoots inC. peruvianus seems most frequent in medium containing BA at 1.0 mg·l−1 (4.44 μM) and IAA or NAA at 1.0 mg·l−1 (5.71 μM or 5.37 μM respectively), but the frequency of shoot formation in the BA or kinetin and NAA or IAA combinations indicated that any of the combinations tested can be used for multiplication ofC. peruvianus plants regenerated from callus tissue culture. Root formation occurred in all (100%) of the cactus shoots after 9 wk in the same culture medium. All the cacti that developed at the different auxin and cytokin combinations continued growth after transfer to a potting mix of red earth (Paleudult) and ground river sand (1∶1).
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TL;DR: The results from these experiments revealed that the morphogenetic pathway (shoot versus root differentiation) can be manipulated on flax explants by raising the 2,4-D level from 0.05 to 3.2 mg l−1 in the induction medium.
Abstract: The effects of plant growth regulators (PGR) on calli induction, morphogenesis and somatic embryogenesis of flax were studied. The organogenic and callus formation capacity were assessed for different types of source explants. Root and shoot explants were equally good material for calli production but the former produced calli without shoot regeneration capacity. Under the experimental conditions tested, 2,4-dichlorophenoxyacetic acid (2,4-D) + zeatin was the most efficient PGR combination on calli induction and biomass production. The calli were green but with no rhizogenic capacity. In contrast, and at similar concentrations, indole-3-butyric acid (IBA) + kinetin induced white or pale green friable calli with a good root regeneration capacity (60%). A factorial experiment with different combinations of 2,4-D + zeatin + gibberellic acid (GA3) levels revealed that the direction of explant differentiation was determined by specific PGR interactions and concentrations. The results from these experiments revealed that the morphogenetic pathway (shoot versus root differentiation) can be manipulated on flax explants by raising the 2,4-D level from 0.05 to 3.2 mg l−1 in the induction medium. The induction and development of somatic embryos from flax explants was possible in a range of 2,4-D + zeatin concentrations surrounding 0.4 mg l−1 2,4-D and 1.6 mg l−1 zeatin, the most efficient growth regulator combination.
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TL;DR: Regenerants were successfully micropropagated, although callus formation caused by zeatin and high 2iP levels interfered with shoot proliferation, and cells from callus and suspension cultures did not exhibit regeneration in any of the media that supported organogenesis from leaves.
Abstract: Ohelo (V. pahalae Skottsb.) and bilberry (V. myrtillus L.) shoots were regenerated via direct organogenesis from whole leaves and leaf sections and also from hypocotyl explants of bilberry. Explants preincubated for 1 to 2 weeks in darkness yielded 75% regeneration frequencies and the highest number of regenerating shoots/explant on TDZ-supplemented media (0.9 to 2.7 μM). When 2iP or zeatin were substituted as the cytokinin source, frequencies of regeneration and shoot productivity were significantly lower. Explants held under constant illumination (no dark pretreatment) had significantly lower regeneration frequencies in all tested cytokinin-supplemented media. 2,4-D stimulated callus formation, but did not support regeneration from vegetative explants. Cells from callus and suspension cultures did not exhibit regeneration in any of the media that supported organogenesis from leaves. Regenerants were successfully micropropagated, although callus formation caused by zeatin and high 2iP levels interfered with shoot proliferation. Zeatin induced hyperhydricity in shoots from both species, but more severely in ohelo. Ex vitro rooting after treatment with 4.9 μM IBA or 5.4 μM NAA was 95 % and 60% successful for bilberry and ohelo, respectively, and plants were readily acclimatized after an interval in a fog chamber. Bilberry microshoots also rooted in vitro in the absence of growth regulator treatment. Chemical names used: 1H-indole-3-butanoic acid (IBA); N-(3-methyl-2-butenyl)-1-H-purine-6-amine (2iP); 6-furfurylaminopurine (kinetin); 1-naphthaleneacetic acid (NAA); thidiazuron=1-phenyl-3-(1,2,3-thiadiazio-5-yl)urea (TDZ); 2,4-dichlorophenoxyacetic acid (2,4-D); 6-(4-hydroxy-3-methylbut-2-enylamino) purine (zeatin).
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TL;DR: Flowering required a 4-day exposure to BA, but shoot formation could be initiated even without exposure toBA, and the sucrose treatment affected the flower bud size distribution.
Abstract: Branch internodes of mature plants and stem internodes of seedlings of Fortunella hindsii flowered in vitro on half-strength MT (Murashige and Tucker 1969) basal medium supplemented with benzyladenine, adenine, 6-γ-γ-dimethylallylaminopurine and kinetin. The highest percentage of flowering was achieved with explants originating from branch internodes of flowering plants close to the apex on half-strength MT basal medium containing 5% sucrose and 0.01 mg 1−1 BA in light. Exposure to darkness for more than 3 weeks followed by re-exposure to light reduced flowering. Flowering required a 4-day exposure to BA, but shoot formation could be initiated even without exposure to BA. First branch internode segments on MT basal medium containing 5% sucrose were prolific in flower (85%) production. The sucrose treatment affected the flower bud size distribution. There were about 13 flower buds per culture in the largest size category (>5 mm).
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TL;DR: Growth of stem callus was faster than needle callus growth and Supplementation of ascorbic acid amongst various anti-phenolic agents tested significantly reduced browning of initiated callus.
Abstract: Culture conditions have been standardized for initiation of callus cultures of Himalayan yew (Taxus wallichiana) using young stem and needle explants from mature trees. Cultures were established on a modified Murashige and Skoog's medium supplemented with various levels of auxins (2.4-D, NAA) and cytokinin (kinetin). A medium containing 0.25 mg/l kinetin and 5.0 mg/l 2.4-D was optimal for stem callus growth whereas the presence of 0.25 mg/l kinetin along with 3.0 mg/l NAA in the medium supported optimal needle callus growth. Growth of stem callus was faster than needle callus growth. Supplementation of ascorbic acid (30 mg/l) amongst various anti-phenolic agents tested significantly reduced browning of initiated callus. Two taxanes (2-deacetoxytaxinine 1 and 2'-deacetoxyaustrospicatine) known to occur in stem bark, have also been isolated from undifferentiated tissue of T. wallichiana in equal or higher yields, for the first time.
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TL;DR: Two controlled environment experiments were conducted to examine the effect of GA3 and kinetin on seedling emergence and early seedling development at a 10°C RZT, and GA3 was more effective than Kinetin at promoting seedling emerged and development of corn and soybean.
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TL;DR: Media containing sucrose alone generally supported more callus proliferation, but the sucrose/sorbitol combination improved regeneration of some cultivars, and NAA and kinetin had little effect on regeneration.
Abstract: This study was conducted to establish and optimize a regeneration system for adapted U.S. rice genotypes including three commercial rice cultivars (LaGrue, Katy, and Alan) and two Arkansas breeding lines. Factors evaluated in the study were genotype, sugar type, and phytohormone concentration. The system consisted of two phases, callus induction and plant regeneration. In the callus induction phase, mature caryopses were cultured on MS medium containing either 1% sucrose combined with 3% sorbitol or 4% sucrose alone, and 0.5 to 4 mg·L−1 (2.26 to 18.10 μM) 2,4-D with or without 0.5mg·L−1) (2.32 μM) kinetin. In the plant regeneration phase, callus was transferred to 2,4-D-free MS medium containing 0 or 2 mg·L−1 (9.29 μM) kinetin combined with 0 or 0.1 mg·L−1 (0.54 μM) NAA. Callus induction commenced within a week, independent of the treatments. Callus growth and plant regeneration, however, were significantly influenced by interactions among experimental factors. Generally, the greatest callus growth and plant regeneration were obtained with 0.5 mg·L−1 (2.26 μM) 2,4-D and decreased with increasing 2,4-D concentrations. Kinetin enhanced callus growth only when combined with 0.5 mg·L−1 (2.26 μM) 2,4-D, and 4% sucrose. Inducing callus on kinetin-containing medium generally enhanced regeneration capacity in the presence of sucrose but not with a sucrose/sorbitol combination. Media containing sucrose alone generally supported more callus proliferation, but the sucrose/sorbitol combination improved regeneration of some cultivars. NAA and kinetin had little effect on regeneration.
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TL;DR: Leaf segments of Prunus persica (L.) Batsch ‘Elberta Queen’ were collected from in vitro-grown proliferating shoots and cultured onto a basal medium supplemented with a wide range of TDZ concentrations (3 to 23 µM), and caulogenesis was observed along cut margins of leaf explants.
Abstract: SummaryLeaf segments of Prunus persica (L.) Batsch ‘Elberta Queen’ were collected from in vitro-grown proliferating shoots and cultured onto a basal medium containing half-strength Murashige and Skoog (MS) salts, Staba vitamins, 30 g l−1 sucrose and 6.5 g l−1 Difco-bacto agar. The influences of six growth regulators supplemented at three levels (5, 10 and 15 µM) on callus induction were investigated under light conditions (16 h photoperiods). For all growth regulator treatments, caulogenesis was observed along cut margins of leaf explants. Among cytokinins tested, thidiazuron (TDZ) induced compact green calli, 6-benzyladenine (BA) and zeatin induced small calli, and kinetin failed to induce callus. For auxin treatments, both dicamba and 2,4-D induced friable white to yellowish calli. In another experiment, leaf explants collected from greenhouse-grown ‘Bellaire’ and in vitro-grown ‘Elberta Queen’ were cultured onto the basal medium supplemented with a wide range of TDZ concentrations (3 to 23 µM). Cauloge...
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TL;DR: Markedly increased levels of free, soluble bound and insoluble bound tyramine and phenylethylamine determined in explants coincided with the period of strongly promoted cell division, and a correlation between aromatic monoamine levels and differentiation processes occurring in EC was observed.
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TL;DR: Because of the high organogenic competence revealed by the spontaneous clone on modified Murashige and Skoog medium, several hormones in different combinations were tested to optimize conditions for adventitious shoot regeneration in this clone.
Abstract: Plant regeneration was achieved from both a spontaneous clone (Braganca) and Brewer's Gold variety ofHumulus lupulus. The results obtained for these two different genotypes were compared. The organogenic ability of petiole and stem segments was tested on three different basal media supplemented with 0.025 mg (0.14 μM) indole-3-acetic acid/L and 2 mg (8.87 μM) 6-benzylaminopurine (N6-benzyladenine)/L. These conditions induced rather heterogeneous responses, which depended mainly on the explant source and the genotype. Because of the high organogenic competence revealed by the spontaneous clone on modified Murashige and Skoog medium, several hormones in different combinations were tested to optimize conditions for adventitious shoot regeneration in this clone. The best relation between the average shoot number/callus and the regeneration rate was achieved with 0.025 mg (0.14 μM) indole-3-acetic acid/L and 2 mg (8.87 μM) 6-benzylaminopurine/L or with 0.02 mg (0.11 μM) indole-3-acetic acid/L and 1.5 mg (6.97 μM) kinetin/L, which enabled 72 and 59% of regeneration, respectively. The regenerated plantlets could be acclimatized with 90% success.
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TL;DR: Higher concentrations of benzyladenine and Zeatin were required to enhance shoot formation in silktree, compared to TDZ, and thidiazuron was highly effective in stimulating shoot formation at low concentrations (<1 μM.
Abstract: Root segments (1 cm long) were excised from 15–20 day old seedlings of silktree (Albizzia julibrissin) grown on B5 medium. About 50% of the control (no growth regulators added) root explants formed shoot buds within 15 days after placement on the culture medium. After 30 days, there were about 4 shoots per control explant. Addition of low levels of various auxins (0.5 μM) did not influence the formation of shoot buds from the explants. Higher concentrations (5μM), however, decreased shoot regeneration. Kinetin and 2iP did not influence shoot regeneration at the concentrations tested (1 & 10 μM). Addition of benzyladenine, Zeatin, or thidiazuron to the culture medium increased both the percentage of explants that formed shoots and the number of shoots per explant. Thidiazuron was highly effective in stimulating shoot formation at low concentrations (<1 μM). At 0.05 μM thidiazuron, 95% of the explants produced shoots and about 10 shoots were formed per explant. Compared to TDZ, higher concentrations (10 μM) of benzyladenine and Zeatin were required to enhance shoot formation. Upon excision and transfer to B5 medium, regenerated shoots developed into normal rooted plantlets.
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TL;DR: Cytological study of induced roots confirmed the haploid nature of calluses and the influence of temperature and kinetin pretreatment on induction of androgenic calluses was examined.
Abstract: Anthers of Morus indica L., with microspores at the uninucleate stage were cultured; and the influence of temperature and kinetin pretreatment on induction of androgenic calluses was examined. The effects of various pretreatments revealed that 24 h cold pretreatment increased the percentage of cultures inducing callus. First microspore division was observed after 16 to 20 days of culture. Th anthers split and developed embryogenic calluses on MB medium supplemented with NAA (0.5 mg l−1 and BA (1.0 mg l−1)) using 8% sucrose. Rhizogenesis was induced on medium supplemented with NAA and BA (each 0.5 mg l−1) with reduced myo-inositol (75 mg l−1). Cytological study of induced roots confirmed the haploid nature of calluses. Different type of embryos were initiated upon transfer of calluses to medium supplemented with NAA, BA (each 0.5 mg l−1), 2,4-d (1.0 mg l−1) and PVP (600 mg l−1). These embryoids further developed roots on removal of 2,4-d from the medium and developed precociously without developing cotyledons and formed elongated shoots.
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TL;DR: The chinese tree Camptotheca acuminata produces the anti-cancer and anti-retroviral drug camptothecin and clonal propagation of this important medicinal plant through shoot bud culture developed gave the highest percentage of rooting and shortest root initiation period.
Abstract: The chinese tree Camptotheca acuminata produces the anti-cancer and anti-retroviral drug camptothecin. Methods were developed for the clonal propagation of this important medicinal plant through shoot bud culture. Shoot buds were excised from 25 to 30 day old seedlings, presoaked for 48 h in three different liquid media containing either BA (2.22–17.4 μM), kinetin (2.32–18.58 μM), or thidiazuron (0.1–10 μM) and were subsequently cultured on semi-solid medium of the same composition. Multiple shoots only developed from the 6-benzyladenine presoaked explants with the maximum number of shoots initiated from buds presoaked in and grown on B5 medium containing 17.4 μM 6-benzyladenine. Individual shoots were removed from clusters and rooted on B5 supplemented with indole-3-butyric acid (4.9–19.6 μM). The lowest concentration of indole-3-butyric acid (4.9 μM) gave the highest percentage of rooting (82%) and the shortest root initiation period (18 d). Over 90% of the in vitro rooted plantlets survived transfer to soil.
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TL;DR: The growth regulator dicamba was significantly better than 2,4-dichlorophenoxyacetic acid in promoting somatic embryogenesis and subsequent plant regeneration, and somatic embryos developed well.
Abstract: Basal media and plant growth regulators were tested for the promotion of somatic embryogenesis from immature wheat-rye hybrid embryos. Influence of growth regulators and chilling on plant regeneration were tested on two media. A medium containing four amino acids-glutamine, arginine, glycine and aspartic acid-as the nitrogen source, promoted the production of, on average, twice as much embryogenic callus as the other media, and somatic embryos developed well. The growth regulator dicamba was significantly better than 2,4-dichlorophenoxyacetic acid in promoting somatic embryogenesis and subsequent plant regeneration. Germination of somatic embryos on both regeneration media was enhanced by cold treatment. Supplementing 190-2 plant regeneration medium with a combination of α-naphthaleneacetic acid + benzyladenine, indole-3-acetic acid + kinetin or indole-3-acetic acid + zeatin resulted in equally high germination rates.
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TL;DR: It is postulated that those new enzyme forms which arise in esterase as well as in superoxide dismutase may either arise de novo or due to post-transcriptional modification of the genes and are essential for shoot tip multiplication of Plantago ovata.
Abstract: Callus cultures were established from hypocotyl explants of Plantago ovata in Murashige and Skoog's medium supplemented with 2,4-d/Kinetin and NAA/BA combinations. Calluses growing on NAA/BA (0.4 mg l−1 each) regenerated into plantlets after the second subculture when transferred to media containing IAA (0.2 mg l−1) and BA (5 mg l−1). Shoot tip multiplication was carried out in the same media with IAA and BA. Tissue samples from calluses, regenerating plantlets and multiplying shoot tips grown in vitro were extracted with protein extraction buffer and subjected to esterase and superoxide dismutase isozyme analysis. The calluses however, showed a uniform banding in esterase even when grown on different hormone combinations. The multiplying shootlets showed two new bands which were not found in either the control or the regenerating plants. A new band was also found in the multiplying shootlets when analysed for superoxide dismutase. It is postulated that those new enzyme forms which arise in esterase as well as in superoxide dismutase may either arise de novo or due to post-transcriptional modification of the genes and are essential for shoot tip multiplication of Plantago ovata.
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TL;DR: The efficiency of plant regeneration, via somatic embryogenesis without an intervening callus phase, was increased by optimizing the culture conditions and the morphogenic pathways governing plant regeneration from spikelets of the immature rice inflorescence were dependent upon the growth-regulator composition of the culture medium.
Abstract: Characterization and optimization of the embryogenic response from in-vitro-cultured immature inflorescences of rice (Oryza sativa L. sub-species indica and japonica) are described. Histological and morphological analyses revealed that the parenchymatous ground tissue present in the region between the second whorl of sterile bracts and the base of the fertile bracts, the embryogenically competent region (ECR), was involved in the embryogenic response. Initial cell divisions within the ECR occurred in the vicinity of the pro-vascular regions of the spikelet. Continued cell divisions resulted in groups of proliferating units and each single proliferating unit was the product of a coordinated behavior of neighboring cells functioning as a morphogenic group. Further proliferation of this embryogenic tissue was due to the development of cambium-like tissue(s) often forming an embryogenic stratum which under optimal culture conditions produced plants at a high frequency. The morphogenic pathways governing plant regeneration from spikelets of the immature rice inflorescence were dependent upon the growth-regulator composition of the culture medium. Three different modes of plant regeneration were observed: (i) direct plant regeneration, (ii) plant regeneration with an intervening callus phase (prolific non-embryogenic growth associated with unorganized, loose and mucilaginous tissue), and (iii) plant regeneration without an intervening callus phase (compact embryogenie tissue with highly organized growth). The efficiency of plant regeneration, via somatic embryogenesis without an intervening callus phase, was increased by optimizing the culture conditions. In a two-step procedure, immature inflorescences of rice were first cultured on a conditioning medium supplemented with 2.0 mg · 1−1 2,4-dichlorophenoxyacetic acid + 1.5 mg · 1−1 kinetin + 0.75 mg · 1−1 α-naphthaleneacetic acid for a period of two weeks. The conditioning medium, with the appropriate culture conditions, allowed redirection of partially differentiated cells of the ECR into embryogenically competent pro-embryogenic groups. Maturation of these pro-embryogenic groups was achieved by transferring them to an embryo proliferation medium, and plants could then be regenerated at a high frequency upon their transfer to the regeneration medium.