The research focused on the changes of phenolic compounds as well as their antiradical activity and reducing power isolated from Amur grape (Vitis amurensis) seeds during germination under optimal conditions and under osmotic stress. The seeds were found to contain tannins, (+) catechin, (-) epicatechin, and gallic acid (in free, ester-and glycoside-bound forms). Extracts from the seeds were also shown to contain two other phenolic acids: caffeic and p-coumaric acids, in very low levels. During a 3-day seed germination test under osmotic stress (-0.5 MPa), the content of total phenolics, tannins and phenolic acids declined as compared to the control. However, seed germination under stress conditions led to a significant increase in the amount of catechins. Because catechin is the one of the units in condensed tannins, its dynamic increase during seed germination may be involved in metabolism of tannins under osmotic stress. It is also likely that the synthesis of catechins is greater under stress conditions and these compounds may be engaged in the process of acclimatization of grapevines to stress conditions. The content of total phenolic compounds in seed extracts is positively correlated with their antioxidant properties. The extracts from seeds germinated under optimal conditions exhibited strong antiradical properties against the DPPH (2,2-diphenyl-1-picrylhydrazyl) radical as well as reducing power. As regards the extracts from grape seeds germinated under osmotic stress, this capability was much weaker. The research demonstrated that antioxidants could interfere with the oxidation process induced by various stresses by acting as oxygen scavengers, therefore the tolerance to drought stress might be correlated with an increase in the antioxidant potential.

A proteomic study was conducted on caryopses of barley cv. Stratus (Hordeum vulgare). The caryopses were germinated in darkness at 20°C, according to one of the three experimental setups: (a) in distilled water for 24 h, followed by 100 mM NaCl for another 24 h (salinity stress, SS); (b) in 100 lM abscisic acid for 24 h, with rinsing in distilled water to remove residual ABA, followed by 100 mM NaCl for another 24 h (pretreatment with ABA ? salinity stress, ABAS); and (c) only in distilled water, for comparison with the tested samples (control, C). After 48 h, proteomes were extracted from barley sprouts in each treatment, according to the method by Gallardo et al. (2002a, b, modified). Proteins were then separated by 2DE and analyzed by MALDI-TOF/MS (Bruker). Under salinity stress, we observed changes in the pattern of proteins involved in: (a) energy metabolism, (b) one-carbon metabolism, (c) cell wall biogenesis, lignification, and adhesion, (d) response to oxidative stress, desiccation stress, and other defense responses, (e) structure and organization of the cytoskeleton, (f) signal transduction, transcription and translation processing, and (g) protein turnover. Our results revealed that ABA can alter the response of barley seedlings to salinity stress. In general, ABA pretreatment limited stress-induced proteomic changes. Alterations in energy and one-carbon metabolism indicate the importance of ABA in glycolytic/gluconeogenic pathways and the SMM cycle during salinity stress. Other observations demonstrated the role of ABA in hemicellulose, cellulose and lignin biosynthesis, ROS scavenging, actin CK formation, control of PI signaling, chromatin-mediated mechanism of stress tolerance, mRNA stability, and protection against dehydration.

The influence of exogenous abscisic acid (ABA) on the content of free polysomes (FP), membranebound polysomes (MBP), cytoskeleton-bound polysomes (CBP) and cytomatrix-bound polysomes (CMBP) in triticale germs as well as in vitro protein synthesis by these four polysomal fractions were studied. During translation, proteins were biotinylated for chemiluminescence detection. We have found that ABA changed both the content of FP, MBP, CMP and CMBP in germ tissue, and their subsequent translation activity. At 100 lM ABA, the content of FP and MBP was over fourfold lower compared to the control, whereas the amounts of CBP and CMBP were about two-and threefold higher, respectively. Moreover, the estimation of the share of polysomes in each ribosomal fraction (sub-units, monosomes, polysomes) showed that, at 100 lM ABA, cytomatrix-bound polysomes, which constituted 90% of polysomes, were the predominant class in ABA-treated germs while membrane-bound polysomes, which made up 82% of polysomes, dominated in the control. A high level of CMBP in ABA-treated tissues may indicate that this class of polysomes participates in ABAinduced synthesis of proteins. In turn, the inhibition of MBP under ABA-treatment is probably due to the delayed protein synthesis which takes place on these polysomes. We identified two lysine-containing proteins synthesized on both of the above classes of polysomes, whose synthesis was altered due to ABA application. Synthesis of a 47 kDa protein on MBP was inhibited, while synthesis of a 79 kDa protein on CMBP is strongly enhanced by ABA influence. The importance of these findings is discussed.

The aim of this study was to investigate molecular basis of germination inhibition of Triticosecale under the influence of exogenous ABA. Seedlings were isolated from seeds after 48 h of germination in water (control sample) and 100 lM ABA solution. It was observed that the applied concentration of phytohormone caused a significant inhibition of germination and a suppressed contribution of polysomes in the total ribosomal fraction. To identify proteins whose expression was affected by ABA, a proteomic approach employing 2D electrophoresis was used. Proteome maps for both control and ABA-treated samples displayed over 2,200 Coomassie Brilliant Blue-stained spots each. Protein spots showing either increase or decrease in spot intensity under the ABA influence were identified by mass spectrometry. Many of the identified proteins whose expression was stimulated by ABA proved to be stress-related, involved in nucleotide metabolism or playing a regulatory and signal transduction role, whereas proteins whose expression decreased are known to be involved in numerous metabolic pathways (including energy, carbohydrate or nucleotide metabolism) as well as related to genetic information processing and protein synthesis. Our results show that the germination inhibition caused by ABA is a result of multigene, diversified actions leading together to triticale growth suppression.

The study analyzed caryopses of barley (Hordeum vulgare) cv. Stratus. Caryopses were germinated in darkness at 20°C in three experimental setups: (a) in distilled water for 24 hours, followed by 100 mM NaCl for another 24 hours (salinity stress, SS), (b) in 100 μM of abscisic acid for the first 24 hours, followed by rinsing with distilled water to remove residual ABA, and in 100 mM NaCl for another 24 hours (ABA pretreatment + salinity stress, ABAS), (c) in distilled water only (control, C). Changes in the content of free polysomes (FP), membrane-bound polysomes (MBP), cytoskeleton-bound polysomes (CBP) and cytomatrix-bound polysomes (CMBP) were examined in barley sprouts germinated in SS and ABAS treatments for 48 hours. In salt-stressed barley sprouts, the concentrations of membrane-bound and cytoskeleton-bound polysomes (MBP, CBP and CMBP) decreased significantly, whereas an increase was noted only in the free polysome (FP) fraction. ABA pretreatment altered the distribution of polysomes in stressed plants. The content of cytoskeletonbound polysomes (CBP and CMBP) increased, FP levels decreased, whereas no changes in MBP content were observed in response to ABA treatment. Our results suggest that plants respond to salt stress by increasing the concentrations of free polysomes that are probably released from damaged cell structures, mainly membranes. Our present and previous findings indicate that ABA could inhibit the release of FP in stressed plants by enhancing polysome binding to the cytoskeleton.