Kinetin

About: Kinetin is a research topic. Over the lifetime, 7856 publications have been published within this topic receiving 135550 citations. The topic is also known as: Kinetin.

Regulation of lateral root formation in lettuce (Lactuca sativa) seedling roots: Interacting effects of α-naphthaleneacetic acid and kinetin

Abstract: Growth substances, α-naphthaleneacetic (NAA) and kinetin, had an important role in the regulation of lateral root (LR) formation in lettuce (Lactuca sativa L. cv. Grand Rapids) seedling roots. NAA (10-5M) was a potent stimulator of LR initiation and caused a 600% increase in the number of lateral root primordia (LRP) compared to untreated roots. NAA was required for only the first 20 h of the 72 h treatment period for maximum stimulation of LRP initiation. Kinetin (2 × 10-5M) effectively prevented the spontaneous formation of LRP and inhibited the NAA-stimulated production of LRP. Kinetin inhibition was maximal during the first 20 h of NAA treatment and this effect was not overcome by subsequent supply of NAA. Also, lettuce roots were most sensitive to kinetin at 20 h of NAA treatment, when the first signs of cell division were observed in the pericycle.

Interaction of cytokinin, auxin, and gibberellin on peroxidase isoenzymes in tobacco tissues cultured in vitro

Abstract: Peroxidase in tobacco callus tissue (Nicotiana tabacum, cv. White Gold) was resolved into three groups of isoenzymes by polyacrylamide gel electrophoresis, and a combined action of cytokinin, auxin, and gibberellin in their formation was clearly demonstrated. The most significant change was in a group of fast-migrating isoperoxidases, the development of which required both kinetin and indoleacetic acid. Kinetin was most stimulatory at 0.2 μM but became inhibitory with increasing concentrations. Indole acetic acid was effective at concentrations from 0.1 to 100 μM with an optimum at 10 μM. With both kinetin and indoleacetic acid at optimal concentrations, addition of gibberellic acid further increased the contents of the fast migrating isoperoxidases, but it was inactive in the absence of indoleacetic acid or in the presence of kinetin in 5 μM or higher concentrations. Cycloheximide, actinomycin D, and abscisic acid inhibited the formation of the fast-migrating peroxidases. Formation of the fast-migrating ...

Modulation of callus growth and secondary metabolites in different Thymus species and Zataria multiflora micropropagated under ZnO nanoparticles stress.

Abstract: Thymus species are aromatic plants with diverse applications in food industries and medicine. This study was conducted to evaluate the potential effect of ZnO nanoparticles (NPs) on callus proliferation and thymol and carvacrol production in three Thymus species, that is, T. vulgaris, T. daenensis, and T. kotschyanus, and Zataria multiflora. For this purpose, callus induction was performed on Murashige and Skoog (MS) medium containing different plant growth regulators (PGRs). After optimization of callus growth, the effects of different concentrations of ZnO NPs (100 and 150 mg L-1 ) were investigated. MS containing 2 mg L-1 of 2, 4-dichlorophenoxy acetic acid (2,4-D) and 1 mg L-1 of kinetin (Kin) revealed significantly highest fresh weight (0.18 g) of callus in T. kotschyanus. Callus growth rate (0.079 mm day-1 ) was found highest in T. vulgaris under similar conditions. Moreover, highest callus induction (92.50%) was achieved by T. kotschyanus in MS containing 2.5 mg L-1 of 2,4-D. Regarding the highest content of thymol (22.8 mg L-1 ) and carvacrol (0.68 mg L-1 ) evaluated by high-performance liquid chromatography, best results were achieved under 150 mg L-1 of ZnO NPs in T. kotschyanus and T. daenesis, respectively. This is simple and cost-effective method to be applied on industrial level for production of enhanced secondary metabolites content.

Correlation between Auxin Resistance and the Lack of a Membrane-Bound Auxin Binding Protein and a Root-Specific Peroxidase in Nicotiana tabacum

Abstract: The levels of a membrane-bound auxin binding protein (MABP) and a root-specific peroxidase (RSP) were studied in several tobacco (Nicotiana tabacum L.) cell lines including an auxin-resistant variant. Groups of cell lines were distinguished which behaved differentially with respect to MABP and RSP depending on the hormonal composition of the medium. In cell lines in which there existed a correlation between the presence or absence of MABP and that of RSP both phenotypes were expressed if kinetin (1-2 micromolar) was supplied. In contrast, neither MABP nor RSP could be detected under any hormonal conditions tested in the auxin-resistant variant which retains the ability to differentiate shoots but lacks the ability to differentiate roots. About an eightfold increase in the concentration of MABP and a dramatic increase in the activity of RSP occurred in a transformant by a mutant strain of Agrobacterium tumefaciens lacking an intact cytokinin gene when it was grown on medium containing 1 to 2 micromolar kinetin. A correlation between auxin resistance and the lack of MABP and RSP suggests that MABP might be involved in auxin-mediated root differentiation in tobacco.

Enhanced somatic embryogenesis in sorghum bicolor from shoot tip culture

Abstract: Shoot tip cultures from 2- to 3-d-old seedlings ofSorghum bicolor (L) Moench cv IS3620C develop highly embryogenic callus from which plants can be regenerated when transferred to plant growth regulator-free medium Isolated shoot tips were cultured on Murashige and Skoog medium supplemented with 25 mg/liter 2,4-dichloro-phenoxyacetic acid and 005 mg/liter kinetin Purple pigmentation characteristic of sorghum cultures on growth regulator-free medium is virtually eliminated with the shoot tip culture Embryogenic callus is white and hard with an undulating appearance but can be separated into multiple bipolar structures by application of gentle pressure The well-developed embryos have a cup-shaped scutellum These germinate like zygotic embryos and develop root-shoot axis Lack of vascular connections to the parent tissue and the synchronous development of the plumule and radicle suggest that these embryos may be of unicellular origin In contrast, when the entire seedling serves as the explant, all meristematic centers in the shoot, including the coleoptile sheath close to the apical meristem respond to plant growth regulators in the medium by callus formation Upon subsequent reculture onto growth regulator-free medium several modes of development occur The differential response of these tissues to identical culture conditions indicate the presence of different population of cells that respond differently to exogenous plant growth regulators