Phenolic compounds constitute a substantial group of phenylpropanoids which are produced by plants as secondary metabolites with antioxidant properties. The spectrum and concentrations of phenolic acids serve as a convenient marker of plant resistance to biotic stresses. Phenolics form also an important component of animal diet. Apples are a widely available fruit exhibiting significant concentrations of antioxidants, especially phenolics and carotenoids. Generally, the concentrations and composition of antioxidants vary during ripening and subsequent handling of harvested fruits.
Our research group is mainly involved in the studies of the metabolism and physiological functions of growth regulators, polyamines and phenolic compounds in plants. We investigate the role of these biologically active compounds in plant development and in the response of plants to abiotic stresses.
In our experiments we use the diverse plant systems from the whole plants to the cell cultures. Our research is primarily focused on somatic embryogenesis of conifers. In the scope of this theme we study the regulation of somatic embryo development, the role of phytohormones in somatic embryogenesis and the effects of abiotic stresses on somatic embryos.
We use a wide array of approaches:
Microscopy – light, confocal and electron microscopy, enhanced by advanced computer image analysis
Biochemical methods – studies of activities of enzymes involved in metabolism of biologically active compounds (e.g. radiometry)
Molecular biology methods – specific gene expressions, and transformation of tissue cultures
Analytical methods – qualitative and quantitative determination of biologically active compounds by gas- and liquid chromatography in tandem with mass spectroscopic detection (cooperation with the IEB Laboratory of mass spectrometry).
Cytological, Biochemical and Molecular Events of the Embryogenic State in Douglas-fir (Pseudotsuga menziesii [Mirb.])
Somatic embryogenesis techniques have been developed for most coniferous species, but only using very juvenile material. To extend the techniques’ scope, better integrated understanding of the key biological, physiological and molecular characteristics of embryogenic state is required. Therefore, embryonal masses (EMs) and non-embryogenic calli (NECs) have been compared during proliferation at multiple levels.
In summary, the exposure of Norway spruce EC to UV-B radiation at different stages of maturation had the strongest effect on cell viability of embryos at early stages of development and resulted in the inhibition of somatic embryo development and/or the substantial decrease in the number of embryos. The extent of cell damage was dependent on the UV-B dose applied, as well as the embryo developmental stage, and might be related to differentiation of the outermost cell layers and formation of protoderm.
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.
Repetitive somatic embryogenesis induced cytological and proteomic changes in embryogenic lines of Pseudotsuga menziesii (Mirb.)
This first report of cellular and molecular changes after repetitive somatic embryogenesis in conifers shows that each cycle enhanced the structure and singularization of EMs through modulation of growth regulator pathways, thereby improving the line´s embryogenic status.