Typy publikací: Časopis

Phenolic compounds play important roles in plant defences against both biotic and abiotic stressors, and many in crop plants are highly beneficial for human health, but their quantities and profiles are influenced by numerous factors. Thus, the purpose of this study was to quantify free and glycosylated phenolic acids in apples (important sources of beneficial phenolics) in the course of fruit development, at harvest and during 5 months of storage.

Frequent duplications of the FLOWERING LOCUS T (FT) gene across various taxonomic lineages resulted in FT paralogs with floral repressor function, whereas others duplicates maintained their floral-promoting role. The FT gene has been confirmed as the inducer of photoperiodic flowering in most angiosperms analyzed to date.

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.

The objective of this work was to induce and detect somaclonal variation in arracacha (Arracacia xanthorrhiza) plants regenerated via indirect morphogenesis, in order to evaluate the potential of this technique to produce new genotypes for breeding purposes of this crop.

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.

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.