Štítky: fytohormony

Somatic embryogenesis of conifers yields somatic embryos (SEs) that closely resemble non-mature cotyledonary zygotic embryos (ZEs). The most common method to improve the biochemical composition of SEs and reduce their water content to bring SEs closer to fully mature ZEs is cold treatment or desiccation at different relative humidity (RH). Both treatments can not only lead to successful SE germination but can also induce a stress response.

Our expertise cover methods of anatomy, histochemical detections, and indirect immunofluorescence, determination of the content of plant hormones, and analysis of gene expression. Newly we are also implementing methods of in-vitro virus detection. To control the developmental processes of in-vitro cultures, we use a broad spectrum of newly synthesized bioactive molecules as well as modulators of plant hormone metabolism and perception (e.g. anti-auxins, anti-gibberellins, cytokinin derivatives).

The transition from vegetative growth to reproduction is an essential commitment in plant life. It is triggered by environmental cues (day length, temperature, nutrients) and regulated by the very complex signaling gene network and by phytohormones. The control of flowering is well understood in Arabidopsis thaliana and in some crops, much less is known about the other angiosperms.

The survival and adaptation of angiosperms depend on the proper timing of flowering. The weedy species Chenopodium ficifolium serves as a useful diploid model for comparing the transition to flowering with the important tetraploid crop Chenopodium quinoa due to the close phylogenetic relationship. The detailed transcriptomic and hormonomic study of the floral induction was performed in the short-day accession C. ficifolium 459. The plants grew more rapidly under long days but flowered later than under short days.

Seed dormancy is an adaptive mechanism that allows seed germination under suitable environmental conditions. Germination of stored dormant seeds proceeds after dormancy breaking induced by stratification. To improve understanding of dormancy breaking in beechnuts, we: investigated effects of moisture content and temperature during storage; analysed contents of abscisic acid, abscisic acid metabolites and indole-3-acetic acid in embryonic axes during storage and stratification; and histochemically localized storage proteins.

Conifer somatic embryogenesis (SE) is a process driven by exogenously supplied plant growth regulators (PGRs). Exogenous PGRs and endogenous phytohormones trigger particular ontogenetic events. Complex mechanisms involving a number of endogenous phytohormones control the differentiation of cells and tissues, as well as the establishment of structures and organs. Most of the mechanisms and hormonal functions in the SE of conifers have not yet been described.