Influence of 2,4-D and BAP on callus growth and the subsequent regeneration of somatic embryos in long-term cultures of Pelargonium x domesticum cv. Madame Layal

This long-term study demonstrates for the first time that it is possible to propagate embryogenic cultures in pelargoniums and to subsequently initiate the differentiation of embryos using the cultivar Madame Layal ( Pelargonium x domesticum ). Propagation of callus was only possible with combinations of 2,4-dichlorophenoxyacetic acid (2,4-D) and 6-benzylaminopurine (BAP), which gave rise to embryos from the primary culture stage on. However, the propagation of cells, as well as the differentiation of embryos, was inhibited by a continuous application of these growth regulators. For this reason, a long period on medium lacking growth regulators was necessary before the differentiation of embryos occurred again. The consequences for improving the propagation of embryogenic cultures in pelargoniums are discussed

Nitrogen remobilisation facilitates adventitious root formation on reversible dark-induced carbohydrate depletion in Petunia hybrida

Supplemental data of Figures 2 to 7. (PDF 31 kb

Comprehensive transcriptome analysis unravels the existence of crucial genes regulating primary metabolism during adventitious root formation in Petunia hybrida

To identify specific genes determining the initiation and formation of adventitious roots (AR), a microarray-based transcriptome analysis in the stem base of the cuttings of Petunia hybrida (line W115) was conducted. A microarray carrying 24,816 unique, non-redundant annotated sequences was hybridized to probes derived from different stages of AR formation. After exclusion of wound-responsive and root-regulated genes, 1,354 of them were identified which were significantly and specifically induced during various phases of AR formation. Based on a recent physiological model distinguishing three metabolic phases in AR formation, the present paper focuses on the response of genes related to particular metabolic pathways. Key genes involved in primary carbohydrate metabolism such as those mediating apoplastic sucrose unloading were induced at the early sink establishment phase of AR formation. Transcriptome changes also pointed to a possible role of trehalose metabolism and SnRK1 (sucrose non-fermenting 1- related protein kinase) in sugar sensing during this early step of AR formation. Symplastic sucrose unloading and nucleotide biosynthesis were the major processes induced during the later recovery and maintenance phases. Moreover, transcripts involved in peroxisomal beta-oxidation were up-regulated during different phases of AR formation. In addition to metabolic pathways, the analysis revealed the activation of cell division at the two later phases and in particular the induction of G1- specific genes in the maintenance phase. Furthermore, results point towards a specific demand for certain mineral nutrients starting in the recovery phase

Influence of 2,4-D and BAP on callus growth and the subsequent regeneration of somatic embryos in long-term cultures of Pelargonium x domesticum cv. Madame Layal

This long-term study demonstrates for the first time that it is possible to propagate embryogenic cultures in pelargoniums and to subsequently initiate the differentiation of embryos using the cultivar Madame Layal ( Pelargonium x domesticum ). Propagation of callus was only possible with combinations of 2,4-dichlorophenoxyacetic acid (2,4-D) and 6-benzylaminopurine (BAP), which gave rise to embryos from the primary culture stage on. However, the propagation of cells, as well as the differentiation of embryos, was inhibited by a continuous application of these growth regulators. For this reason, a long period on medium lacking growth regulators was necessary before the differentiation of embryos occurred again. The consequences for improving the propagation of embryogenic cultures in pelargoniums are discussed

Somatic embryo-like structures of strawberry regenerated <i style="mso-bidi-font-style:normal">in vitro</i> on media supplemented with 2,4-D and BAP

739-745Somatic embryo-like structures (SELS) were produced in vitro from leaf disk and petiole explants of two cultivars of strawberry (Fragaria × ananassa Duch) on Murashige and Skoog medium with different concentrations and combinations of 2,4‑dichlorophenoxyacetic acid (2,4-D), 6-benzylaminopurine (BAP) and sucrose to check the embryonic nature of these structures histologically. A large number of SELS could be regenerated in both cultivars on media with 2 - 4 mg L-1 2,4-D in combination with 0.5 - 1 mg L-1 BAP and 50 g L-1 sucrose. Histological examination of SELS revealed the absence of a root pole. Therefore these structures cannot be strictly classified as somatic embryos. The SELS formed under the tested culture conditions represent malformed shoot-like and leaf-like structures. The importance of these results for the propagation of strawberries via somatic embryogenesis is discussed

Additional file 1: of Nitrogen remobilisation facilitates adventitious root formation on reversible dark-induced carbohydrate depletion in Petunia hybrida

Experiments 1-9 of nitrogen preconditioning of cuttings. (PDF 22 kb

Cluster analysis.

<p>Two major clusters of genes specifically induced during different phases of AR formation created via K-means clustering method by Genesis software. Three types of associated expression graphs of each cluster are shown. SEP: Sink Establishment Phase; RP: Recovery Phase; MP: Maintenance Phase.</p