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Showing papers on "Zeatin published in 2014"


Journal ArticleDOI
TL;DR: It is shown that an ATP-binding cassette transporter in Arabidopsis, AtABCG14, is essential for the acropetal (root to shoot) translocation of the root-synthesized cytokinins.
Abstract: Cytokinins are a major group of phytohormones regulating plant growth, development and stress responses. However, in contrast to the well-defined polar transport of auxins, the molecular basis of cytokinin transport is poorly understood. Here we show that an ATP-binding cassette transporter in Arabidopsis, AtABCG14, is essential for the acropetal (root to shoot) translocation of the root-synthesized cytokinins. AtABCG14 is expressed primarily in the pericycle and stelar cells of roots. Knocking out AtABCG14 strongly impairs the translocation of trans-zeatin (tZ)-type cytokinins from roots to shoots, thereby affecting the plant's growth and development. AtABCG14 localizes to the plasma membrane of transformed cells. In planta feeding of C(14) or C(13)-labelled tZ suggests that it acts as an efflux pump and its presence in the cells directly correlates with the transport of the fed cytokinin. Therefore, AtABCG14 is a transporter likely involved in the long-distance translocation of cytokinins in planta.

200 citations


Journal ArticleDOI
TL;DR: The ability of Rhizobacteria to produce cytokinins and thereby stimulate rhizodeposition may be important in enhancing rhizobacterial colonization of the rhizoplane.

117 citations


Journal ArticleDOI
TL;DR: Using high‐performance liquid chromatography‐mass spectrometry, strain ZJSH1 was found to produce various phytohormones, including salicylic acid (SA), indole‐3‐acetic acid (IAA), Zeatin and abscisic acid (ABA), which provides a potential for application in the commercial growth of D. officinale.
Abstract: Summary Growth-promoting Sphingomonas paucimobilis ZJSH1, associated with Dendrobium officinale, a traditional Chinese medicinal plant, was characterized. At 90 days post-inoculation, strain ZJSH1 significantly promoted the growth of D. officinale seedlings, with increases of stems by 8.6% and fresh weight by 7.5%. Interestingly, the polysaccharide content extracted from the inoculated seedlings was 0.6% higher than that of the control. Similar growth promotion was observed with the transplants inoculated with strain ZJSH1. The mechanism of growth promotion was attributed to a combination of phytohormones and nitrogen fixation. Strain ZJSH1 was found using the Kjeldahl method to have a nitrogen fixation activity of 1.15 mg l−1, which was confirmed by sequencing of the nifH gene. Using high-performance liquid chromatography-mass spectrometry, strain ZJSH1 was found to produce various phytohormones, including salicylic acid (SA), indole-3-acetic acid (IAA), Zeatin and abscisic acid (ABA). The growth curve showed that strain ZJSH1 grew well in the seedlings, especially in the roots. Accordingly, much higher contents of SA, ABA, IAA and c-ZR were detected in the inoculated seedlings, which may play roles as both phytohormones and ‘Systemic Acquired Resistance’ drivers. Nitrogen fixation and secretion of plant growth regulators (SA, IAA, Zeatin and ABA) endow S. paucimobilis ZJSH1 with growth-promoting properties, which provides a potential for application in the commercial growth of D. officinale.

90 citations


Journal ArticleDOI
TL;DR: The effect of meta-Topolin (mT), an aromatic natural cytokinin, on micropropagation and adventitious shoot regeneration was evaluated on Prunus rootstocks, Torinel (Prunus domestica L.) and Ferdor (PRunus insititia ǫ× domestica), in vitro shoots were grown for three subcultures on a multiplication medium containing 2.1, 4.2 or 6.3μm of mT or 2.6-benzyladenine (BA) as mentioned in this paper.
Abstract: The effect of meta-Topolin (mT), an aromatic natural cytokinin, on micropropagation and adventitious shoot regeneration was evaluated on Prunus rootstocks, Torinel (Prunus domestica L.) and Ferdor (Prunus insititia × domestica). In vitro shoots were grown for three subcultures on a multiplication medium containing 2.1, 4.2 or 6.3 μM of mT or 2.1 µM N 6-benzyladenine (BA). Then, apical leaves were excised and transferred on a medium supplied with BA, thidiazuron (TDZ) or zeatin for adventitious regeneration. Shoots multiplied on 2.1 μM mT or BA, were also induced to root with α-naphthalene acetic acid and acclimatized. meta-Topolin did not improve shoot proliferation, respect to BA, however, positively influences growth and quality of shoots. Ferdor from mT showed higher rooting percentage (92 %), root number and length, respect to the control, while a similar response was observed in Torinel with both cytokinins. Acclimatisation was higher than 90 % for both genotypes and, after 5 months, the highest length of roots was found in plants from mT. Adventitious regeneration was obtained only in leaves from shoots previously grown on mT. The highest regeneration responses, 65 and 42 %, respectively for Ferdor and Torinel, were obtained in the regeneration medium supplied with TDZ.

75 citations


Journal ArticleDOI
TL;DR: Impact of CCCP on cytokinin concentrations and delivery in xylem sap and on accumulation in shoots of 7-day-old wheat plants in the presence and absence of exogenous cytokinins applied as zeatin is reported.
Abstract: Cytokinin flow from roots to shoots can serve as a long-distance signal important for root-to-shoot communication. In the past, changes in cytokinin flow from roots to shoots have been mainly attributed to changes in the rate of synthesis or breakdown in the roots. The present research tested the possibility that active uptake of cytokinin by root cells may also influence its export to shoots. To this end, we collapsed the proton gradient across root membranes using the protonophore carbonyl cyanide m-chlorophenylhydrazone (CCCP) to inhibit secondary active uptake of exogenous and endogenous cytokinins. We report the impact of CCCP on cytokinin concentrations and delivery in xylem sap and on accumulation in shoots of 7-day-old wheat plants in the presence and absence of exogenous cytokinin applied as zeatin. Zeatin treatment increased the total accumulation of cytokinin in roots and shoots but the effect was smaller for the shoots. Immunohistochemical localization of cytokinins using zeatin-specific antibodies showed an increase in immunostaining of the cells adjacent to xylem in the roots of zeatin-treated plants. Inhibition of secondary active cytokinin uptake by CCCP application decreased cytokinin accumulation in root cells but increased both flow from the roots and accumulation in the shoots. The possible importance of secondary active uptake of cytokinins by root cells for the control of their export to the shoot is discussed.

42 citations


Journal ArticleDOI
TL;DR: The influence of plant growth regulators on biomass growth and the accumulation of medicinally-relevant isoflavone phytoestrogens, derivatives of genistein and daidzein in callus cultures of Genista tinctoria was examined.
Abstract: The influence of plant growth regulators on biomass growth and the accumulation of medicinally-relevant isoflavone phytoestrogens, derivatives of genistein and daidzein (8 compounds including aglycones, glucosides and glucoside esters) in callus cultures of Genista tinctoria (Fabaceae) was examined. The experiments included 10 auxins [2,4-dichlorophenoxyacetic acid (2,4-D), p-chlorophenoxyacetic acid, indole-3-acetic acid, indole-3-butyric acid, indole-3-propionic acid, 1-naphthaleneacetic acid, β-naphthoxyacetic acid, picloram, 2,3,5-triiodobenzoic acid (TIBA), 2,4,5-trichlorophenoxyacetic acid (2,4,5-T)] and 7 cytokinins [6-benzylaminopurine, forchlorfenuron, 1,3-diphenylurea, 2-isopentenyladenine, kinetin (KIN), thidiazuron, zeatin] applied at 0.5 and 5.0 mg l−1, jointly with 5.0 or 0.5 mg l−1 KIN or 2,4-D (for auxins and cytokinins, respectively—36 phytohormone combinations in total). Statistical analysis of the relationships between callus growth [expressed as growth index (Gi)] and the accumulation of isoflavones showed positive correlation in the cytokinin group (rxy values from 0.13 to 0.61) and negative correlation within auxins (rxy values from −0.31 to −0.39). Among the cytokinins tested, the highest isoflavone content (6,436.26 mg/100 g dry weight) and the fastest biomass growth (Gi = 892.46 %) were obtained for 0.5 mg l−1 KIN used jointly with 5.0 mg l−1 2,4-D. In the group of auxins, the combination of 0.5 mg l−1 TIBA and 5.0 mg l−1 KIN provided the fastest culture growth (Gi = 983.07 %) and the isoflavone concentration of 10,474.23 mg/100 g dry weight, which is so far the highest amount of these metabolites achieved in callus cultures of higher plants.

41 citations


Journal ArticleDOI
TL;DR: A simple and efficient regeneration protocol was established for soybean and Cotyledonary node explants from 7-day-old in vitro seedlings were used as explants to investigate the effect of different plant growth regulators and polyamines on regeneration using direct organogenesis system.
Abstract: A simple and efficient regeneration protocol was established for soybean [Glycine max (L.) Merrill]. Cotyledonary node explants from 7-day-old in vitro seedlings were used as explants. The effect of different plant growth regulators [N 6 –benzyladenine (BA), kinetin (KT), thidiazuron (TDZ), gibberellic acid (GA3), zeatin riboside (ZTR), indole-3-acetic acid (IAA), and indole-3-butyric acid (IBA)] along with polyamines (Spermidine, spermine, and putrescine) were investigated at different stages of regeneration using direct organogenesis system. Exogenous spermidine (137.69 μM) in shoot induction medium containing optimal BA concentration (2.22 μM) induced maximum number of shoots (39.02 shoots/explant) compared to BA (2.22 μM) alone. Regenerated shoots elongated well in shoot elongation medium containing GA3 (1.45 μM) and spermine (74.13 μM), and developed profuse roots in root induction medium containing putrescine (62.08 μM). Rooted plantlets were successfully hardened and acclimatized with a survival rate of 92 %. The amenability of the standardized protocol using cultivar PK 416 was tested on four more Indian soybean cultivars JS 90–41, Hara soy, Co1, and Co2 of which PK 416 was found to be the best responding cultivar, with a maximum of 96.94 % shoot induction.

39 citations


Journal ArticleDOI
02 Sep 2014-Rice
TL;DR: In response to stress, OsSUV3 rice plants maintained plant hormone levels that regulate the expression of several stress-induced genes and reduce adverse effects of salt on plant growth and development and therefore sustains crop productivity.
Abstract: The SUV3 (suppressor of Var 3) gene encodes a DNA and RNA helicase, which is localized in the mitochondria. Plant SUV3 has not yet been characterized in detail. However, the Arabidopsis ortholog of SUV3 (AT4G14790) has been shown to be involved in embryo sac development. Previously, we have reported that rice SUV3 functions as DNA and RNA helicase and provides salinity stress tolerance by maintaining photosynthesis and antioxidant machinery. Here, we report further analysis of the transgenic OsSUV3 rice plants under salt stress. The transgenic OsSUV3 overexpressing rice T1 lines showed significantly higher endogenous content of plant hormones viz., gibberellic acid (GA3), zeatin (Z) and indole-3-acetic acid (IAA) in leaf, stem and root as compared to wild-type (WT), vector control (VC) and antisense (AS) plants under salt (200 mM NaCl) stress condition. A similar trend of endogenous plant hormones profile was also reflected in the T2 generation of OsSUV3 transgenic rice under defined parameters and stress condition. In response to stress, OsSUV3 rice plants maintained plant hormone levels that regulate the expression of several stress-induced genes and reduce adverse effects of salt on plant growth and development and therefore sustains crop productivity.

36 citations


Journal ArticleDOI
TL;DR: An improved protocol for highly efficient production of doubled haploid loose-curd cauliflower plants (Brassica oleracea var. botrytis) via microspore culture is presented, which efficiently produced embryos from both tight- and loose-called donor plants, although the embryo yields were genotype dependent.
Abstract: We present an improved protocol for highly efficient production of doubled haploid loose-curd cauliflower plants (Brassica oleracea var. botrytis) via microspore culture. Our experiment explored factors such as donor plant treatment, flower bud pretreatment, embryo germination medium, and ploidy characterization of regenerated plants. Our technique efficiently produced embryos from both tight- and loose-curd donor plants, although the embryo yields were genotype dependent. We achieved a germination rate of around 30 % by employing a hormone combination of zeatin, indole-3-acetic acid, and 6-benzylaminopurine pretreatment culture. We also used 1–4 days of cold pretreatment of the flower buds, which were submerged into NLN-13 medium, to induce microspore embryogenesis. Analysis using an FCM Ploidy Analyzer showed that more than 50 % of regenerated plants were spontaneously doubled haploids, more than 25 % were tetraploids, and fewer than 7 % were haploid. Visual examination of plants in the field revealed that they had distinct phenotypic characteristics relating to their ploidy level. The efficient production of double haploids using our improved microspore culture technique is a promising approach that can be applied in loose-curd cauliflower breeding programmes and genetic research.

33 citations


Journal ArticleDOI
TL;DR: This review chronicles the development of the cytokinin research during the last 30 years by addressing the fundamental questions concerning the prevalence of cis-zeatin in monocotyledonous crops and in dicotinous legumes and potato/sweet potato.
Abstract: This review chronicles the development of the cytokinin research during the last 30 years. Cytokinin and auxin are the two major plant growth hormones that control virtually all aspects of growth and development in higher plants. The pathways for cytokinin biosynthesis and metabolism have been characterized by the identification of isopentenyl pyrophosphate transferase, cytokinin oxidases, cytokinin hydroxylase, zeatin cis-/trans-isomerase, cytokinin phosphoribosyl hydrolases, cytokinin-specific riboside phosphorylase, and others enzymes. Loss-of function mutant phenotypes of cytokinin degradation/activating enzymes indicate the regulation of concentration and spatial distribution of bio-active cytokinin plays a pivotal role in the increase in panicle size, in the numbers of floral organs, and eventually in seed yield. One of the most fundamental questions in the cytokinin field is one concerning the prevalence of cis-zeatin in monocotyledonous crops (rice and maize) and in dicotyledonous legumes (pea, chickpea) and potato/sweet potato. A hypothesis is that cis-zeatin is synthesized by the cis-specific hydroxylation of the terminal methyl group of N6-isopentenyl side chain of N6-isopentenyl adenosine (i6Ado) or of their mono-, di-, or tri-phosphates catalyzed by the cis-specific hydroxylase. A second potential pathway is the isomerization of trans-zeatin to cis-zeatin by zeatin cis-/trans-isomerase. A second fundamental question to be addressed is the physiological role of cis-zeatin. Some have argued for a special function of cis-zeatin to account for the prevalence of the cis-zeatin in the plant kingdom from algae to higher plants.

31 citations


Journal ArticleDOI
TL;DR: Phytohormone immunolocalization analysis suggested that IAA involved in differentiation and development of each floral organs, GA and zeatin play important roles in floret primordia differentiation and ovule development and IAA signaling is involved in the pedicel and corolla elongation and delay flowering slightly.

Journal ArticleDOI
TL;DR: The results suggest that the difference in somatic organogenesis capacity observed in peach and peach×almond hybrids is markedly affected by the endogenous hormonal content of the studied genotypes.

Journal ArticleDOI
TL;DR: The results of the present study confirmed the therapeutic potency of S. corymbosa used in the traditional medicine and developed a protocol for in vitro production which could be applied for mass multiplication and for the conservation of germplasm.
Abstract: Swertia corymbosa (Griseb.) Wight ex C. B. Clarke, a valuable medicinal plant, has been investigated for its regeneration potential using nodal explants. Out of a range of concentrations of cytokinins [6-benzyl adenine (BA), 6-furfurylaminopurine (Kn), 2-isopentenyl adenine (2iP), thidiazuron (TDZ), and zeatin (Z)] used as supplements with MS, BA at 4.40 μM concentration proved best for multiple shoot induction yielding 26.50 ± 0.26 shoots after 12 weeks of culture. Addition of low concentration of NAA (1.3 μM) in MS medium supplemented with the cytokinin BA (4.40 μM) favoured shoot multiplication. A mean number of 35.78 ± 0.81 shoots were produced per explant. Additive effect of BA (4.40 μM) in combination with Kn (4.64 μM) produced highest number of shoots (83.20 ± 4.29). Addition of GA3 (1.4 μM) to the above medium not only favored shoot elongation but also enhanced the number of shoots (113.98 ± 3.80). The microshoots were rooted successfully on half-strength MS medium supplemented with 9.8 μM of IBA. The plantlets were successfully transferred to hardening medium containing vermiculite with 87 % survival rate. Screening of the antibacterial, antioxidant activity and estimation of total phenolic and flavonoid content of methanolic extracts of micropropagated plants were also carried out and compared with that of the wild-grown plants. In all the tests, methanolic extract from wild-grown plants showed higher antioxidant, antimicrobial activity, total phenolic and flavonoid content than in vitro propagated plants. The content of secondary metabolites in wild-grown plants and in vitro propagated plants was determined by HPLC coupled with ESI-MS and the presence of loganic acid, swertiamarin, sweroside, gentiopicroside, isovitexin, amoroswertin, amarogentin, gentiacaulein, decussatin, and swertianin in the samples were confirmed. Gentiopicroside (40.726 mg/g) and swertianin (29.598 mg/g) were found to be the major compounds which may be responsible for the antimicrobial and antioxidant activities. The results of the present study confirmed the therapeutic potency of S. corymbosa used in the traditional medicine; in addition, the protocol for in vitro production developed in the present study could be applied for mass multiplication and for the conservation of germplasm.

Journal ArticleDOI
TL;DR: The results of this experiment have clearly shown that Cr has epigenetic effect as well as genotoxic effect and some of phytohormones decreasing (GA, ZA and IAA) and especially increasing of ABA levels under Cr stress may be a part of the defense system against the stress.
Abstract: In this research, we aimed to evaluate DNA damage levels, DNA methylation, protein and phytohormone levels changes in corn (Zea mays L.) seedlings exposed to chromium nitrate (Cr). The results showed that the used all chromium doses caused a decreasing mitotic index, genomic template stability and soluble protein levels and increasing in RAPDs profile changes (DNA damage) and DNA hypermethylation. In additional, in the high-pressure liquid chromatography analyses, it was also observed that Cr contamination caused a decreasing in the growth-promoting hormones including gibberellic acid (GA), zeatin (ZA) and indole acetic acid (IAA) levels, in contrast to abscisic acid (ABA) level. The results of this experiment have clearly shown that Cr has epigenetic effect as well as genotoxic effect. Some of phytohormones decreasing (GA, ZA and IAA) and especially increasing of ABA levels under Cr stress may be a part of the defense system against the stress.

Journal ArticleDOI
TL;DR: Histological analyses showed that adventitious buds originated from cell proliferation within the pericycle, opposite the protoxylem poles of the explant, and gave rise to the highest percentage of morphologically normal regenerated plants.
Abstract: The organogenic potential of root explants derived from cultured seedlings of Bixa orellana L. (annatto) was investigated in response to different incubation conditions and either 4.44 μM 6-benzyladenine, 4.54 μM Thidiazuron, or 4.56 μM Zeatin. Explants cultured in liquid media with agitation generally showed better development of adventitious buds versus explants cultured on semi-solid media. The most adventitious buds developed from explants cultured in liquid media under a 16-h photoperiod. Use of Zeatin and Thidiazuron promoted the development of more adventitious buds than 6-benzyladenine but morphological abnormalities among regenerating shoots and plants were observed. Fewer adventitious buds developed from explants cultured in liquid media supplemented with 6-benzyladenine, but the buds gave rise to the highest percentage of morphologically normal regenerated plants. Histological analyses showed that adventitious buds originated from cell proliferation within the pericycle, opposite the protoxylem poles of the explant. Seedling root tissue is useful for in vitro propagation of B. orellana.

Journal ArticleDOI
TL;DR: The reported results seem to confirm the supposition, that hormones act as an important factor contributing to regulation of both uptake and distribution of ions in the whole plant.
Abstract: Bean plant seedlings grown in water culture were treated for 5 days either with NaCl or with 7-times concentrated nutrient solution (diminished water potential by 3-10 3 hPa in both cases). Control and stressed plants were treated for 24 hrs with zeatin and GA,. NaCl-stress reduced distinctly ion absorption rate (K, Ca and P). Zeatin and GA 3 promoted potassium uptake, but only in NaCI-treated plants. These hormones diminished Na accumulation in metabolically active organs but increased P- and Ca-content. In plants grown under both kind of stresses zeatin and GA 3 partially reestablished the ratio of the main mono- to divalent cations, which increased in the leaves and apical part of the stressed plants. ABA introduced into the nutrient solution caused inhibition of the ion uptake (K, Ca, Mg and P). similar to that caused by NaCl-stress. The above reported results seem to confirm the supposition, that hormones act as an important factor contributing to regulation of both uptake and distribution of ions. In this way growth substances may also participate in the regulation of transport of various substances (among others - assimilates) in the whole plant.

Journal ArticleDOI
TL;DR: Which hormones are external PGRs-dependent and what is the weight of the genotype and hormones in peach organogenesis that provide an avenue to manipulate in vitro organogenesis in peach are shown.

Journal ArticleDOI
TL;DR: Plant and anther nutrient starvation did not improve the anther response to differentiation, nor did it induce haploid development, similarly as cold treatment of inflorescences or isolated anthers.
Abstract: In the present investigation, aimed at obtaining beet haploids from anthers, the effect of mineral media, potato and sugar beet extract and p-fluorophenylalanine (PFP) in combination with growth substances was tested. Nutrient-starved plants as anther-donors, anther-starvation, cold treatment and photoperiod were also analysed. On all mineral media the anthers produced callus and roots; however, the percentage depended on the combination of growth substances used. The best medium for differentiation was that of Linsmaier and Skoog with 25 µM zeatin or 6-(3-methyl-2-butenylamino)purine with 5 µM naphthalene-l-acetic acid (25.5%). The addition of PFP caused an increase in the percentage of anther differentiation (41.6%). Besides callus and roots on one of the anthers (in ca. 140000 tested), vegetative buds were formed from which numerous plants were obtained (2n). Plant and anther nutrient starvation did not improve the anther response to differentiation, nor did it induce haploid development, similarly as cold treatment of inflorescences or isolated anthers. The anthers of wild species showed lower ability to differentiate than those of sugar or fodder beets. Cytological analyses showed formation of multicellular structures until ca. the 12-th day of anther culture; afterwards, they degenerated.

Journal ArticleDOI
TL;DR: The results indicate that root-derived cytokinin concentration in leaves influences ryegrass regrowth at different clip heights, and regrowth index, calculated as newly grown leaf biomass divided by unit stubble weight, was used to evaluate regrowth capacity at different clipping heights.
Abstract: The effect of clipping height on ryegrass regrowth was investigated by examining the roles of several plant hormones. Our study consisted of three treatment conditions: (1) darkness over whole plants, (2) darkness only over stubble leaf sheaths, and (3) light over whole plants. Results showed that under darkness over whole plant, low stubble height resulted in low leaf regrowth biomass. Similar leaf regrowth biomass was observed under conditions of darkness only over stubble leaf sheaths as well as light over whole plants. Each unit weight of stubble at different clipping heights has relatively similar potential of providing stored organic substance for leaf regrowth. Therefore, regrowth index, calculated as newly grown leaf biomass divided by unit stubble weight, was used to evaluate regrowth capacity at different clipping heights under minimal influence of organic substances stored in stubbles. Under light over whole plants and single clipping, low stubble height and high stubble height with root thinning resulted in low leaf biomass and high regrowth index. On the other hand, under light over whole plants and frequent clipping high leaf biomass and regrowth index were observed in high stubble height. In addition, we found that leaf zeatin and zeatin riboside (Z + ZR) affected ryegrass regrowth and that roots regulated leaf Z + ZR concentration. Thus, our results indicate that root-derived cytokinin concentration in leaves influences ryegrass regrowth at different clipping heights.

Journal ArticleDOI
TL;DR: It was established that tomato varieties have a substantially greater ability to indirect shoot organogenesis compared with the F1 hybrid.
Abstract: The influence of explant type as well as of the type of growth regulators and concentration on callus induction processes and somatic organogenesis of shoots was studied in vitro on four tomato genotypes of Russian breeding. Cytological study of callus tissue was conducted. It was established that tomato varieties possess a substantially greater ability to indirect shoot organogenesis compared with the F1 hybrid. The highest frequency of somatic organogenesis of shoots, as well as their number per explant, was observed for most of the genotypes studied during the cultivation of cotyledons on Murashige-Skoog culture medium containing 2 mg/l of zeatin in combination with 0.1 mg/l of 3-indoleacetic acid. An effective protocol of indirect somatic organogenesis of shoots from different explants of tomato varieties with a frequency of more than 80% was developed.

Journal ArticleDOI
TL;DR: Zeatin at the lowest concentration provided the best results for shoot proliferation of all 26 treatments and can be recommended for micropropagation of D. intermedia.
Abstract: This study was aimed to optimize in vitro propagation of Drosera intermedia for commercial and conservation purposes. The effect of concentration of MS nutrients (⅛ MS, ¼ MS, ½ MS and, MS), various pH (3.7-7.7), sucrose concentration (10-40 g l -1 ) and cytokinins (0.1-3 mg l -1 ), namely BA (N6-benzyladenine), kinetin and zeatin were evaluated. After 60 days of shoot cultivation, growth and developmental characteristics (plant height, number of shoots per explant, diameter of rosette, number of roots per explant, length of roots) were recorded. No significant differences were found for various levels of pH and sucrose. On the contrary, plant height was negatively influenced by an increase of nutrients in the medium. The plants on 1/8 MS medium were significantly taller, and displayed higher proliferation capacity compared with those cultivated on full-strength MS medium. Shoot multiplication and growth was suppressed by supplementation of BA and kinetin, regardless of concentration used. Zeatin at the lowest concentration (0.1 mg l -1 ) provided the best results for shoot proliferation of all 26 treatments and can be recommended for micropropagation of D. intermedia.

Journal ArticleDOI
TL;DR: The rapid and sensitive hormonal and vitamin E profiling presented here can help in understanding the key physiological processes underlying fruit ripening and floral senescence.
Abstract: Knowledge of ripeness and regulation of postharvest processes is an important tool to prevent loss of commercial value in both fruit and cut flower markets. The joint analysis of hormones and vitamin E levels can reveal complex interactions between hormones and oxidative stress as key regulators of postharvest processes. Profiling of both groups of metabolic compounds was performed during the ripening of non-climacteric fruits (red raspberry, Rubus idaeus L.) and senescence of ethylene-insensitive flowers (Dutch Iris, Iris x hollandica L.). After an initial extraction of the sample, without further purification steps, the hormonal profile was analyzed by UPLC-MS/MS and vitamin E levels were measured by HPLC. This methodological approach was very fast and had enough sensitivity for the analysis of small samples. Raspberry fruit maturation was characterized by a decline of cytokinin levels [zeatin, zeatin riboside, 2-isopentenyl adenine, and isopentenyl adenosine (Z, ZR, 2-iP, and IPA, respectively)] and gibberellins (GA1 in particular). Exogenous application of ABA prevented δ-tocopherol loss during fruit ripening. Iris floral senescence was also under strict hormonal control, also mediated by cytokinins and gibberellins. Z, ZR, 2-iP, GA9, and GA24 levels decreased in inner tepals, whereas the level of IPA decreased in style-merged-to-stigma tissues, thus suggesting tissue-specific roles for different hormones. α-Tocopherol levels decreased during senescence of inner tepals, hence suggesting enhanced oxidative stress. In conclusion, the rapid and sensitive hormonal and vitamin E profiling presented here can help in understanding the key physiological processes underlying fruit ripening and floral senescence.

Journal Article
TL;DR: These techniques can be used to raise the disease free stock of cabbage and cauliflower for genetic improvement of in-vitro bulk of varieties on commercial scale in a very brief time span.
Abstract: Background: An efficient method of artificial mass propagation was optimized for two very nutritious vegetables of Pakistan, the cabbage and cauliflower. Being an agrarian economy, Pakistan’s more than half of the population depends directly or indirectly on agricultural products. Methodology: Hypocotyls of germinating of seeds (5-7 days old seedlings) were used as explants. Murashige and Skoog basal medium was supplemented with different concentrations of auxin (2,4 Dichlorophenoxy acetic acid) and cytokinin (benzyl amino purine) in combination to study the callus forming tendency of cabbage and cauliflower; and found better if used in ratio of 2:1 (at least) respectively. Results: For evaluation of regeneration potential Kinetin, Zeatin, Gibrellic acid-3, and Indole acetic acid were found good in combination with benzyl amino purine. Higher (than auxin) concentration of cytokinin was found essential to obtain good regeneration response of callus. Conclusion: Effectively concluded that these techniques can be used to raise the disease free stock of cabbage and cauliflower for genetic improvement of in-vitro bulk of varieties on commercial scale in a very brief time span.

Journal ArticleDOI
TL;DR: In this paper, the results showed that all concentrations of the test material caused a decreasing mitotic index, genomic template stability (GTS), and soluble protein levels, but increased RAPDs profile changes (DNA damage) and DNA hypermethylation.
Abstract: In this research we aimed to evaluate DNA damage levels, DNA methylation, and protein and pytohormone level changes in corn seedlings (Zea mays L.) exposed to 5, 10, 20, and 40 mM concentrations of lead sulfate solution (PbSO4). The results showed that all concentrations of the test material caused a decreasing mitotic index, genomic template stability (GTS), and soluble protein levels, but increased RAPDs profile changes (DNA damage) and DNA hypermethylation. Moreover, in the HPLC (high-pressure liquid chromatography) analyses, it was also observed that Pb contamination caused a decrease in the growth-promoting hormones including gibberellic acid (GA), zeatin (ZA), and indole acetic acid (IAA) levels, in contrast to increasing the absisic acid (ABA) level. The results of this experiment have clearly shown that Pb has a significant impact on the epigenetic mechanisms as well as its genotoxic effects. Some of phytohormone decreases (GA, ZA and IAA) and especially increasing ABA levels under Pb stress may be a part of the defense system against stress.

Journal ArticleDOI
TL;DR: Explants originating from seeds, embryos, seedlings and maturing plants of rye were cultured on a modified Murashige and Skoog medium and a Schenk and Hildebrandt medium and mature embryo, isolated radicles and lateral roots formed callus itissue which was only capable of rhizogenesis.
Abstract: Explants originating from seeds, embryos, seedlings and maturing plants of rye were cultured on a modified Murashige and Skoog medium (MS) and a Schenk and Hildebrandt medium (SH). Depending on various combinations and concentrations of NAA (α-tnaphthaleneacetic acid), IAA (β-indoleacetic acid),2,4-D (dichlosaphenoxyacetic acid), 2,4,5-T(trichloraphenoxyacetic acid),2,4-D (dichloraphenoxyacetic acid), 2,4,5-T (trichloraphenoxyacetic = 2 iP), ZEA (zeatin), and GA 3 (gibberellic acid) mature embryo, isolated radicles and lateral roots formed callus itissue which was only capable of rhizogenesis. Leaf segments of 3 and 5-day-old seedlings produced callus and roots, however the rachis of a spike of 7 mm in length was capable of forming shoots which later developed into plants.

Journal ArticleDOI
TL;DR: The highest level of shoot differentiation was obtained from calli derived from fragments of embryo axes obtained in Balila genotype using embryo axes fragments including the basal part of cotyledon on medium with 0.25 mg/L BAP.
Abstract: This study surveyed a rapid, efficient and reproducible protocol for in vitro shoot regeneration and rooting of two Middle East chickpea cultivars (Balila and Wady). Organogenic ability of various explants (decapitated embryo axes, fragments of embryo axes, fragments of embryo axes with basal part of cotyledons, entire and half of cotyledons) was tested on MS media containing different concentrations and nature of cytokinins (BAP and zeatin) or compound with cytokinin-like activity (TDZ). The highest level of shoot regeneration was achieved in Balila genotype using embryo axes fragments including the basal part of cotyledon on medium with 0.25 mg/L BAP. Higher BAP concentrations than 0.25 mg/L for Balila and 0.5 mg/L for Wady caused a decrease of shoot regeneration. On MS media supplemented with zeatin (1, 3 and 5 mg/L) and thidiazuron (1, 3 and 5 mg/L), the highest level of shoot differentiation was obtained from calli derived from fragments of embryo axes. Organogenic ability of calli from Wady genotype was enhanced by increasing zeatin and TDZ concentrations, up to 5 mg/L. Conversely, a progressive decrease of shoot frequency for Balila and root development for both genotypes, were observed with increasing concentrations of BAP, zeatin and TDZ.

Journal ArticleDOI
TL;DR: In vitro culture of young Secale cereale spikes is described with special attention given to changes in development of the rachis, with 2,4,5-T + IPA appeared to be the best combination for callus regeneration.
Abstract: In vitro culture of young Secale cereale spikes is described with special attention given to changes in development of the rachis. 7 mm explants were cultivated on a modified M u r a s h i g e and S k o o g (1962) medium (MS) supplemented with 2,4-D (dichlorophenoxyacetic acid), NAA (α-naph-thaleneacetic acid), IAA (β-indoleacetic acid), 2,4,5-T (trichlorophenoxyacetic acid), and ZEA (zeatin), KIN (kinetin), BAP (6-benzylaminopurine), IPA (izopentenyladenine or 2 iP) in numerous combinations and concentrations. Rachises differentiated branches with node construction in the presence of synthetic auxin. Rhizogenesis of explants was stimulated by 2,4-D and 2,4,5-T. 2,4,5-T + IPA appeared to be the best combination for callus regeneration. Many meristematic centres were found previously and combinations of NAA + KIN stimulated direct, whereas 2,4-D + ZEA indirect, differentiation of shoot elements. Development was observed from plantlets to flowering plants.

Journal ArticleDOI
TL;DR: The effects of fruit on bud sprouting and vegetative growth were compared on fruiting and defruited loquat trees from fruit set onward and there is no evidence that they are responsible for bud burst.
Abstract: The effects of fruit on bud sprouting and vegetative growth were compared on fruiting and defruited loquat trees from fruit set onward. Carbohydrate and nitrogen content in leaves and bark tissues and hormone concentrations were studied during the fruit development and vegetative growth periods. On defruited trees, a significant proportion of buds sprouted in winter, whereas buds from fruiting trees sprouted only in the spring when fruit reached its final size. Furthermore, when panicles were completely removed in autumn, the buds also sprouted. In addition, fruit directly affected vegetative growth by reducing shoot length. An effect of sink removal (flower or fruit) promoting bud sprouting, regardless of the season, was then demonstrated. Neither soluble sugar concentration nor nitrogen fraction concentration in leaves or bark tissues was related to bud sprouting, but a certain nutritional imbalance was observed during the most active period of fruit development. Moreover, fruit sink activity significantly modified hormone content by increasing indole-3-acetic acid (IAA) and reducing zeatin concentrations, resulting in a higher IAA/zeatin ratio parallel to the lower bud sprouting intensity. Therefore, these changes caused by fruit removal are all related to vegetative growth, but there is no evidence that they are responsible for bud burst.

Journal Article
TL;DR: A callus induction and plant regeneration protocol was developed from leaf explants of the endemic Spilanthes acmella, finding MS medium containing 2.0 mg/l BAP and 1mg/l Zeatin to be the best medium for maximum in vitro response.
Abstract: A callus induction and plant regeneration protocol was developed from leaf explants of the endemic Spilanthes acmella. Explants were cultured on Murashige and Skoog medium (MS) supplemented with different plant growth regulators (PGRs) [α-naphthaleneacetic acid (NAA), BAP and IBA, 2 4-dichlorophenoxyacetic acid (2, 4-D), Zeatin]. The combinations and concentrations of PGRs were shown significant variations for the frequency of callus formation, appearance of callus and the potential of callus differentiation. 2, 4-D (5mg/lit) alone while BAP 0.5mg/l with NAA 5.0mg/l have been found highly effective in callusing with quite good in texture and friable in nature 90% to 80% respectively along with single shoots. After the callus formation the formed callus were cultured on different combinations of BAP and NAA and BAP and Zeatin for multiple shoots and shoot elongation. MS medium containing 2.0 mg/l BAP and 1mg/l Zeatin was found to be the best medium for maximum in vitro response i.e., 93% shooting and multiple shoots (7.5)with maximum 8cm in length. Best rooting was achieved on half strength MS medium fortified with 1mg/l NAA respectively.

Journal ArticleDOI
TL;DR: A protocol for in vitro culture of immature embryos of C. annuum with relatively low levels of IAA and zeatin provided the highest germination rates, particularly in the advanced stages (torpedo and cotyledonary) and Bola embryos had the highest rates.
Abstract: Common pepper (Capsicum annuum L.) is one of the most important vegetables in the world, and extensive breeding efforts are being made to develop new improved strains of this species. In this regard, in vitro culture of immature embryos may help breeders accelerate breeding cycles and overcome interspecific barriers, among other applications. In this study, we have optimized a protocol for in vitro culture of immature embryos of C. annuum. Levels of indole-3-acetic acid (IAA) and zeatin have been tested to improve the efficiency (germination rates) of this technique in C. annuum embryos at the four main immature stages (i.e. globular, heart, torpedo, and early cotyledonary) from four varietal types of this species (California Wonder, Piquillo, Guindilla, and Bola). The effect of 5-day initial incubation in the dark was also tested on the most efficient hormone formulation. On average, relatively low levels of both IAA and zeatin (0.01 mg L−1 each) (M1) provided the highest germination rates, particularly in the advanced stages (torpedo and cotyledonary). To a lesser extent, the lack of these growth regulators (M0) or high IAA (0.2 mg L−1)/low zeatin (0.01 mg L−1) (M2) combination also had a positive response. On the contrary, high zeatin levels (0.2 mg L−1) produced very low germination rates or callus development (efficiency 0-7 %). Different responses were also found between genotypes. Thus, considering the best media (M0, M1, M2), Bola embryos had the highest rates. M1 plus 5-days of initial dark incubation (M1-D) improved the efficiency rates at all embryo stages, particularly in the earliest (globular) embryos which increased from 3 % to > 20 %.