scispace - formally typeset
Search or ask a question
Author

S. V. S. Nielsen

Bio: S. V. S. Nielsen is an academic researcher. The author has contributed to research in topics: Hypocotyl & Shoot. The author has an hindex of 1, co-authored 1 publications receiving 16 citations.
Topics: Hypocotyl, Shoot, Sativum, Pisum

Papers
More filters
Journal ArticleDOI
TL;DR: A sequential indole-3-acetic acid-zeatin treatment was applied to Pisum sativum hypocotyl explants, resulting in shoot formation from 50% of theExplants, which suggests the shoots to be of de novo origin, which would make the system suitable for transformation experiments.
Abstract: A sequential indole-3-acetic acid (IAA)-zeatin treatment was applied to Pisum sativum hypocotyl explants, resulting in shoot formation from 50% of the explants. Shoots were easily rooted and transplantable plants could be obtained in 3 months. The method has been applicable to the 5 cultivars tested. Histological examination of explants suggests the shoots to be of de novo origin, which would make the system suitable for transformation experiments.

16 citations


Cited by
More filters
Journal ArticleDOI
TL;DR: A clear relationship was observed between the growth regulators employed for bud regeneration and shoot rooting phases and the subsequent competence of the regenerated plants for flowering, pod formation and viable seed production.
Abstract: The production of whole plants from explants of protein pea (Pisum sativum L) using an efficient, reliable and rapid strategy, while maintaining trueness to type, will be required before regeneration can be exploited for genetic transformation Seeds of the pea genotypes Terese, Solara, Frisson and P64 (a hypernodulating mutant line of Frisson) were surface-sterilized and imbibed overnight, whereafter embryo axes were dissected and germinated on hormone-free medium for 7–10 d Hypocotyl sections lacking pre-existing meristems were harvested and cultured on a range of media with various concentrations and combinations of growth regulators in order to induce either caulogenesis or somatic embryogenesis Differences in responsiveness were apparent between genotypes, but regeneration via caulogenesis was consistently more reliable than via the induction of somatic embryos Few explants underwent somatic embryo production and their conversion into plants has remained elusive so far, irrespective of the genotype studied Conversely, large numbers of buds were produced within 10 d by organogenesis, and healthy, rootable shoots were obtained A clear relationship was observed between the growth regulators employed for bud regeneration and shoot rooting phases and the subsequent competence of the regenerated plants for flowering, pod formation and viable seed production

49 citations

Journal ArticleDOI
TL;DR: The regeneration system is efficient as it results in the recovery of 4–5 plants within a period of 8 weeks, starting from an explant, and is highly reproducible and equally effective for all the four genotypes tested.

35 citations

Journal ArticleDOI
TL;DR: The galactose selection system provides a new alternative being distinct from conventional antibiotic and herbicide selection systems as well as so-called positive selection systems where the selective agent has a beneficial effect.
Abstract: A new selection system based on galactose as selective agent and a UDP-glucose:galactose-1-phosphate uridyltransferase gene as selective gene is presented. A broad range of plant species, including agronomically important crops such as maize and rice, is sensitive to low dosages of galactose. The toxicity of galactose is believed to be due to accumulation of galactose-1-phosphate, generated by endogenous galactokinase after uptake. Here, it is demonstrated that this toxicity can be sufficiently alleviated by the Agrobacterium tumefaciens-mediated introduction of the E. coli UDP-glucose:galactose-1-phosphate uridyltransferase (galT) gene, driven by a 35S-promoter, to allow transgenic shoots of potato and oil seed rape to regenerate on galactose containing selection media, resulting in high transformation frequencies (up to 35% for potato). Analysis of genomic DNA and UDP-glucose:galactose-1-phosphate uridyltransferase activity in randomly selected potato transformants confirmed the presence and active expression of the galT gene. The agricultural performance of transgenic potatoes was evaluated by monitoring the phenotype and tuber yield for two generations and these characters were found to be indistinguishable from non-transgenic controls. Thus, the galactose selection system provides a new alternative being distinct from conventional antibiotic and herbicide selection systems as well as so-called positive selection systems where the selective agent has a beneficial effect.

33 citations

Journal ArticleDOI
TL;DR: 16 cultivars of pea were screened in vitro for the formation of somatic embryos which were dependent on the genotype, culture conditions and explant source used and the development of embryos to whole plants was unreliable.
Abstract: Summary In this study 16 cultivars of pea (Pisum sativum L.) were screened in vitro for the formation of somatic embryos which were dependent on the genotype, culture conditions and explant source used. The cultivars Stehgolt, Maro and Progreta showed the highest tendency to form somatic embryos (c. 25%) while Alaska, Rondo and Ascona did not show any embryo production. Using the cultivar Belman, the highest embryo production was achieved by using nodal explants of shoots (10.6%) and a cotyledon-free embryo as explant source (14.1%) in the light (15.8%) compared to using apices as explants (1.8%) and a seedling as the explant source (9.4%) in the dark (3.3%). Media containing picloram (0.75 mg/litre) followed by BA (1 mg/litre) or kinetin (1 mg/litre), each for four weeks gave the highest somatic embryo production. The development of embryos to whole plants was unreliable and some 90% of the embryos induced did not develop any further, died, recallused or formed secondary embryos. The size of the embryo at separation and the timing of the separation from the original callus were important factors determining success for complete development to whole plant. Regeneration of 184 plants was achieved with ensuing flowering, pod formation and viable seed production from the techniques described.

21 citations

Journal ArticleDOI
TL;DR: All the genotypes tested, produced multiple shoots that could be established to mature fertile plant, hence, the medium combinations used were found to be genotype neutral.
Abstract: In-vitro regeneration in fieldpea was achieved from immature embryonic axes and cotyledonary node explants of six genotypes on modified MS media supplemented with different concentration of plant growth regulators, 6-Benzylamino purine (BAP) and Naphthalene acetic acid (NAA). The best regeneration response, leading to multiple shoot formation efficiency (22.34 shoots/explant) was observed in the medium supplemented with 1.0 mg/L BAP and 0.2 mg/L NAA and best frequency (67.55 ± 4.74) was achieved on medium containing 2.0 mg/L BAP and 0.4 mg/L NAA. The shoots were subcultured on a medium supplemented with a combination of 1.0 mg/L GA3, 2.0 mg/L BAP and 0.4 mg/L NAA, which resulted in elongation of 85 % of shoots. Rooting attempted from the elongated shoots, on half strength MS medium and supplemented with three different auxins IBA, IAA and NAA separately, exhibited similar results. Alternatively, micro-grafting of in vitro regenerated shoots onto pre-germinated root stocks raised in green house facility was attempted with high success rate (75 %). The grafted plants could be successfully hardened, fertigated with Hoagland solution and distilled water in a ratio of (1:10) for acclimatization and further development. All the genotypes tested, produced multiple shoots that could be established to mature fertile plant, hence, the medium combinations used were found to be genotype neutral.

13 citations