The Experts below are selected from a list of 306 Experts worldwide ranked by ideXlab platform
Karen Koefoed Petersen - One of the best experts on this subject based on the ideXlab platform.
-
significance of different carbon sources and sterilization methods on Callus induction and plant regeneration of miscanthus x ogiformis honda giganteus
Plant Cell Tissue and Organ Culture, 1999Co-Authors: Karen Koefoed Petersen, Jurgen Hansen, Peter KrogstrupAbstract:Different carbon sources, sterilized by autoclaving or filter-sterilization, were tested during induction, maintenance, and plant regeneration of embryogenic Miscanthus x ogiformis Honda `Giganteus' Callus, derived from various explant types. Explants from small immature inflorescences, between 2.5 and 8 mm, produced more embryogenic Callus than explants from shorter or longer inflorescences, shoot apices or leaf explants. On medium containing mannitol or sorbitol, only small amounts of Callus were induced and no embryogenic Callus was formed. Callus induction and embryogenic Callus formation on shoot apices and immature inflorescences did not differ significantly between media containing sucrose, glucose, fructose, maltose or a mixture of glucose and fructose. However, Callus induction and embryogenic Callus formation from leaf explants were best on glucose. A higher percentage of leaf explants formed Callus on autoclaved sucrose, as opposed to the other carbon sources where filter-sterilization in general resulted in a higher Callus percentage. The growth rate of embryogenic Callus was influenced both by carbon source and sterilization method when less than 1 g of Callus was inoculated. None of the tested carbon sources could considerably improve plant regeneration from M. `Giganteus' Callus, but a higher number of plants tended to be regenerated per Callus piece from filter-sterilized carbon sources.
-
Callus induction and plant regeneration in miscanthus x ogiformis honda giganteus as influenced by benzyladenine
Plant Cell Tissue and Organ Culture, 1997Co-Authors: Karen Koefoed PetersenAbstract:Leaf sections of greenhouse-grown Miscanthus x ogiformis Honda 'Giganteus' plants and leaf sections or shoot apices of in vitro shoot cultures were grown on Murashige and Skoog medium containing various concentrations of benzyladenine (BA) and 2,4-dichlorophenoxyacetic acid. On leaf sections, the Callus induction decreased with increasing BA concentration. The percentage of embryogenic Callus was increased, the percentage of root-forming Callus decreased, and a new shoot-forming Callus type was formed by inclusion of BA during Callus induction. A higher percentage of shoot-forming Callus was formed on shoot apices compared with leaf sections of in vitro-grown shoots when cultured on 0.4 µM BA. The largest number of plants per Callus piece was regenerated from shoot-forming Callus, but maintenance of the high regeneration capacity proved difficult.
-
Callus induction and plant regeneration from different explant types of miscanthus x ogiformis honda giganteus
Plant Cell Tissue and Organ Culture, 1996Co-Authors: Inger Baeksted Holme, Karen Koefoed PetersenAbstract:Different explants of Miscanthus x ogiformis Honda ‘Giganteus’ were tested in order to develop an efficient tissue culture system. Shoot apices, leaf and root sections from in vitro-propagated plants, and leaf and immature inflorescence sections from 6-month-old greenhouse-grown plants were used. The explants were cultured on Murashige and Skoog medium supplemented with 4.5, 13.6, 22.6 or 31.7 μM 2,4-dichlorophenoxyacetic acid. Three types of Callus were formed but only one was embryogenic and regenerated plants. Callus induction and formation of embryogenic Callus depended on the type and developmental stage of the explants. Shoot apices formed the highest percentage of embryogenic Callus. There was a difference in the formation of embryogenic Callus between leaf explants from in vitro-propagated shoots and greenhouse-grown plants. The best results were obtained from newly formed leaves of in vitro-propagated shoots and older leaves of greenhouse-grown plants. Immature inflorescences smaller than 2.5 cm produced a higher percentage of embryogenic Callus than larger more mature inflorescences. Embryogenic Callus derived from immature inflorescences had the highest regeneration capacity. Differences in 2,4-dichlorophenoxyacetic acid concentrations had no significant effect on Callus induction, embryogenic Callus formation and plant regeneration.
B. B. Jarvis - One of the best experts on this subject based on the ideXlab platform.
-
Growth hormone-like activities of macrocyclic trichothecenes in in vitro Callus induction and growth of four Baccharis species
Journal of Plant Growth Regulation, 1992Co-Authors: J. O. Kuti, B. B. JarvisAbstract:The ability of two plant-produced macrocyclic trichothecenes (baccharinoid B4 and roridin E) to induce Callus growth of two trichothecene-producing Baccharis species ( B. coridifolia and B. megapotamica ) and two nontrichothecene-producing species ( B. halimifolia and B. neglecta ) was investigated. Roridin E had no effect in the induction of Callus of B. coridifolia , a roridin-producing plant, but induced Callus of nonroridin-producing plants ( B. megapotamica, B. halimifolia , and B. neglecta ). Baccharinoid B4 stimulated Callus growth of B. megapotamica , a baccharinoid-producing plant, and inhibited growth of B. coridifolia, B. halimifolia , and B. neglecta Callus tissues. The ability of roridin E to induce Callus was most effective at concentrations of 10^−8 and 10^−6 M and when synergistically coupled with auxin, 2,4-dichlorophenoxyacetic acid (2,4-D). The ability of baccharinoid B4 to stimulate Callus growth appeared to increase with increased concentration in the culture medium. Analysis of Callus cultures grown in medium amended with roridin E showed that B4, roridin E, and 8β-hydroxyroridin E and verrucarols were formed in the tissues but not in the medium. The results of this study indicated that while the Callus-inducing ability of roridin E seemed to be nonspecies-specific in nature, the ability of B4 to stimulate Callus was a highly species-specific phenomena. Callus-inducing activity of roridin E may depend on the capacity of plant species to transform exogenous roridin E into baccharinoids or other macrocyclic trichothecene derivatives.
J. O. Kuti - One of the best experts on this subject based on the ideXlab platform.
-
Growth hormone-like activities of macrocyclic trichothecenes in in vitro Callus induction and growth of four Baccharis species
Journal of Plant Growth Regulation, 1992Co-Authors: J. O. Kuti, B. B. JarvisAbstract:The ability of two plant-produced macrocyclic trichothecenes (baccharinoid B4 and roridin E) to induce Callus growth of two trichothecene-producing Baccharis species ( B. coridifolia and B. megapotamica ) and two nontrichothecene-producing species ( B. halimifolia and B. neglecta ) was investigated. Roridin E had no effect in the induction of Callus of B. coridifolia , a roridin-producing plant, but induced Callus of nonroridin-producing plants ( B. megapotamica, B. halimifolia , and B. neglecta ). Baccharinoid B4 stimulated Callus growth of B. megapotamica , a baccharinoid-producing plant, and inhibited growth of B. coridifolia, B. halimifolia , and B. neglecta Callus tissues. The ability of roridin E to induce Callus was most effective at concentrations of 10^−8 and 10^−6 M and when synergistically coupled with auxin, 2,4-dichlorophenoxyacetic acid (2,4-D). The ability of baccharinoid B4 to stimulate Callus growth appeared to increase with increased concentration in the culture medium. Analysis of Callus cultures grown in medium amended with roridin E showed that B4, roridin E, and 8β-hydroxyroridin E and verrucarols were formed in the tissues but not in the medium. The results of this study indicated that while the Callus-inducing ability of roridin E seemed to be nonspecies-specific in nature, the ability of B4 to stimulate Callus was a highly species-specific phenomena. Callus-inducing activity of roridin E may depend on the capacity of plant species to transform exogenous roridin E into baccharinoids or other macrocyclic trichothecene derivatives.
Margit Laimer Câmara Machado - One of the best experts on this subject based on the ideXlab platform.
-
Rhizogenesis in stem discs of Malus pumila rootstock M9 “Jork”: I. Hormonal and environmental effects on root induction and Callus formation
Plant Cell Reports, 1995Co-Authors: Georg J. Seifert, Peter Kanzler, Artur Machado, Hermann Katinger, Margit Laimer Câmara MachadoAbstract:To establish a protocol suited for the molecular characterization of root induction the influences of explant position, etiolation state and orientation as well as temperature and light intensity on root and Callus formation were investigated. Depending on these factors stem discs of Malus incubated on indole-3-butyric acid containing medium and subsequently on hormone-free medium regenerated roots and Callus of “filamentous” and “smooth” texture to a varying extent. Concentration and incubation duration of indole-3butyric acid strongly affected rooting and the production of “smooth” Callus. Moreover “smooth” Callus was profuse at the low light levels applied during rooting. Rooting efficiency decreased and “filamentous” Callus increased between 19°C and 25°C. Explants close to the shoot apex displayed reduced rooting efficiency and profuse “filamentous” Callus. There was a strong effect of explant orientation on root and “filamentous” Callus formation.
Hyonggin An - One of the best experts on this subject based on the ideXlab platform.
-
leg lengthening by distraction osteogenesis using the ilizarov apparatus a novel concept of tibia Callus subsidence and its influencing factors
International Orthopaedics, 2009Co-Authors: Ashok Shyam, Surya Udai Singh, Hitesh N Modi, Hae Ryong Song, Hyonggin AnAbstract:This article studies the incidence and magnitude of delayed Callus subsidence, which will also help in study the hypothesis of three cortex corticalisation to determine the time of fixator removal during distraction osteogenesis (DO). Eighty-one tibia segments with mean lengthening of 7.7 ± 2.9 cm were studied with age, gender, skeletal maturity, amount and percentage of lengthening, Callus pattern, Callus shape, number of cortices seen at the time of fixator removal, bone mineral density (BMD) ratio, and Callus diameter ratio analysed for their effect on Callus subsidence. All segments had tibia Callus subsidence ranging from 4 mm to 3.2 cm with 54% having significant subsidence of more than 1 cm. Multivariate regression analysis revealed only the amount of lengthening and Callus patterns to be significant. In conclusion, we can say that tibia Callus subsidence is a significant delayed complication and factors affecting it can be used to determine the time of fixator removal.
