The Response of Picea abies Somatic Embryos to UV-B Radiation Depends on the Phase of Maturation

Ultraviolet-B (UV-B) radiation is a key environmental signal which initiates diverse responses that affect the metabolism, development, and viability of plants. In keeping with our previous studies, we concentrated primarily on how UV-B radiation affects Norway spruce [Picea abies (L.) Karst.] somatic embryo maturation and how phenolics and polyamines (PAs) are linked to the defense response invoked by UV-B irradiation. We treated clusters of Norway spruce embryogenic culture (EC) with UV-B during the five stages of embryo maturation (early, cylindrical, precotyledonary, cotyledonary, and mature embryos). For the first time, we take an advantage of the unique environmental scanning electron microscope AQUASEM II to characterize somatic embryos in their native state. The severity of the irradiation effect on embryonal cell viability was shown to be dependent on the intensity of radiation as well as the stage of embryo development, and might be related to the formation of protoderm. The response of early embryos was characterized by an increase in malondialdehyde (MDA), a marked decrease in PA contents and a decline in phenolics. The reduced ability to activate the defense system seems to be responsible not only for the severe cell damage and decrease in viability but also for the inhibition of embryo development. The significant reduction in spermidine (Spd), which has been reported to be crucial for the somatic embryo development of several coniferous species, may be causally linked to the limited development of embryos. The pronounced decrease in cell wall-bound ferulic acid might correspond to failure of somatic embryos to reach more advanced stages of development. Embryos at later stages of development showed stress defense responses that were more efficient against UV-B exposure

Metodika pro uchování, exploataci a zpřístupnění obsahu historických divadelních cedulí:Cesta k divadlu

Vývoj metodiky a specifických nástrojů pro uchování, exploataci a zpřístupnění historických divadelních cedulí se zvláštním zřetelem ke sbírkovým fondům Národního muzea v Praze a Moravského zemského muzea v Brně

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. EMs and NECs originating from a single somatic embryo (isogenic lines) of each of three unrelated genotypes were used in the analyses, which included comparison of the lines' anatomy by transmission light microscopy, transcriptomes by RNAseq Illumina sequencing, proteomes by free-gel analysis, contents of endogenous phytohormones (indole-3-acetic acid, cytokinins and ABA) by LC-MS analysis, and soluble sugar contents by HPLC. EMs were characterized by upregulation (relative to levels in NECs) of transcripts, proteins, transcription factors and active cytokinins associated with cell differentiation accompanied by histological, carbohydrate content and genetic markers of cell division. In contrast, NECs were characterized by upregulation (relative to levels in EMs) of transcripts, proteins and products associated with responses to stimuli (ABA, degradation forms of cytokinins, phenols), oxidative stress (reactive oxygen species) and carbohydrate storage (starch). Sub-Network Enrichment Analyses that highlighted functions and interactions of transcripts and proteins that significantly differed between EMs and NECs corroborated these findings. The study shows the utility of a novel approach involving integrated multi-scale transcriptomic, proteomic, biochemical, histological and anatomical analyses to obtain insights into molecular events associated with embryogenesis and more specifically to the embryogenic state of cell in Douglas-fir

Dynamics of cold acclimation and complex phytohormone responses in Triticum monococcum lines G3116 and DV92 differing in vernalization and frost tolerance level

Cold stress response was compared in the crowns, leaves, and roots of Triticum monococcum DV92 spring line and G3116 winter line. The cold exposure was associated with a rapid increase of water saturation deficit, which resulted in a strong up-regulation of abscisic acid. Simultaneously, other stress hormones: salicylic acid, aminocyclopropane carboxylic acid (precursor of ethylene), and jasmonic acid decreased. The stress application resulted in a decrease of hormones associated with stimulation of cell growth and division (gibberellins, cytokinins, and auxin). During the acclimation phase of the stress response, the plants increased their frost tolerance and started the accumulation of dehydrins. Active gibberellin, cytokinins, and auxin were elevated; more rapidly in the spring line. Abscisic acid decrease was accompanied by a gradual increase of the other stress hormones. Simultaneously, the up-regulation of phenolic acids was observed, including ferulic and sinapic acids, which may be involved in the stabilization of auxin levels as well as antioxidative functions. After 21 days, the spring line DV92 exhibited its maximum of active cytokinins, which indicates the onset of the early stage of reproductive development. The winter line fulfilled its vernalization requirement after 42 days, as indicated by a decrease of frost tolerance and dehydrin levels, accompanied by similar growth hormone changes as in DV92. The similarities and differences between einkorn and common wheat in a long-term cold response are discussed. © 2014 Elsevier B.V