Waterlogging of soybean plants (Glycine max L.) led to impaired symbiotic N₂ fixation and a marked decline in glutamine (Gln) concentration in xylem bleeding sap. Xylem Gln concentration increased during the growth cycle of the plant and was correlated with nodule formation. Treatments known to impair N₂ fixation, such as exposing the root system to pure N₂ gas or a mixture of Ar and O₂ (80:20; v/v), led to specific declines in xylem sap Gln. The decrease in Gln observed during waterlogging was also seen on transfer of nodulated plants to aerated hydroponics, where the decline was highly correlated with ureide content in the xylem sap. Upon flooding the nodulated root system, the specific decline in xylem sap Gln could be detected within 10 min and reached a minimum within 60 min, indicating that waterlogging has an immediate effect on N₂ fixation. It is concluded that xylem Gln arises directly from N₂-fixation and is a useful indicator of N₂ fixation activity of symbiotic soybean plants.

A protocol for in vitro propagation of Balkan endemic plant Salvia brachyodon Vandas from nodal segments was developed. 6-benzylaminopurine was more effective in axillary buds promotion when compared to thidiazuron. The rooting of regenerated shoots was induced by transferring them to the media supplemented with auxins. All tested auxins (indole-3-acetic acid, indole-3-butyric acid, and α-naphthaleneacetic acid) stimulated the rooting of S. brachyodon shoots. The acclimatization of in vitro rooted shoots was successful.

Contents of total free [PA(S)] and conjugated polyamines [PA(SH), PA(PH)] were higher in turnip (Brassica rapa L. cv. Rapa) seeds during imbibition (0-36 h) and radicle protrusion (36-48 h) than during the further growth (10 d). Ethylene production was activated with the protrusion, reaching a maximum at the second day of germination and dropping afterwards. The application of ethrel accelerated radicle emergence but the direct intervention of ethylene in the breaking of the seed coat was not clear from the use of ethylene-biosynthesis inhibitors (CoCl₂ and AVG). Finally, in this work the gene BrACO2 was characterized. Although its expression was not detected in seeds through zygotic embryogenesis, it increased concomitantly with the germination process.

Plants of Miscanthus sinensis (cv. Giganteus) were grown in hydroponics for three months in nutrient solution with 0, 2.2, 4.4 and 6.6 μM CdNO₃. Growth parameters, catalase (CAT), guaiacol peroxidase (POD), ascorbate peroxidase (APX) and superoxide dismutase (SOD) activities were analysed in leaves and roots collected after 1-and 3-month exposure. Dry biomass of all miscanthus organs was affected by Cd concentration both after 1-and 3-month exposure. No visible symptoms of Cd toxicity were observed in shoots and rhizomes of plants grown in presence of Cd. In contrast, roots became shorter and thicker and the whole root system more dense and compact already after one month of treatment with 6.6 μM Cd. The lower Cd concentration increased the enzymes activities after 3 months in leaves and only after 1-month in roots, while a decrease in activity was observed at higher Cd concentrations.

The effects of carbon dioxide supply within the range of 1-5 % (along with purified air), on cell culture of Panax ginseng were investigated in a balloon type bubble bioreactor containing 4 dm³ of Murashige and Skoog (MS) medium supplemented with 7.0 mg dm^-3 indolebutyric acid, 0.5 mg dm^-3 kinetin and 30 g dm^-3 sucrose. A 1 % CO₂ supply was found beneficial for the production of cell mass; however, increasing CO₂ concentration to 2.5 and 5 % decreased the biomass accumulation. CO₂ enrichment was not beneficial for saponin production and 1, 2.5, and 5 % CO₂ supply resulted in decrease in saponin accumulation up to 11.6, 19.5, and 50.6 %, respectively.

A modified plant 7SL RNA gene from Arabidopsis thaliana designated AHIIA63M was introduced into potato plants via Agrobacterium-mediated transformation. No transgenic plants could be obtained using pGPTV-based binary vectors where AHIIA63M gene driven by polIII promoter was located close to the polII promoter of the selection gene. Special binary vectors with matrix attachment region (MAR) elements had to be used for transformation to insulate polII and polIII promoters within T-DNA. The level of AHIIA63M RNA in transgenic plants was lower than the levels of transcripts of transgenes driven by RNA polymerase II. The level of AHIIA63M transcript in transgenic potato plants was tissue specific. The highest expression was detected in roots and gynoecium and the lowest in tubers. Moreover, non-specific promoter activity within the MAR element was revealed. This activity contributed to AHIIA63M transcription. This is the first report of expression of a modified 7SL RNA gene in transgenic plants and promoter activity within the MAR element.

A chitinase-like 32 kDa acidic protein with a potential chitinase activity has been identified in the medium of embryogenic suspension cultures of Dactylis glomerata L. using an antiserum raised against endochitinase EP3 from Daucus carota L. The presence of this protein discriminates between Dactylis glomerata L. embryogenic and nonembryogenic suspension cultures and thus could be possibly used as a marker for embryogenic potential.

Protein pattern, ammonia content, glutamine synthetase activity, lipid peroxidation, superoxide dismutase, catalase, peroxidase and peroxidase isoforms were studied in the leaves and roots of 7-d-old peanut (Arachis hypogaea L. cv. JL-24) seedlings treated by 25, 100 and 250 μM jasmonic acid (JA). SDS-PAGE protein profile of leaves and roots after JA application showed a significant increase in 18, 21, 30, 45, 47 and 97.4 kDa proteins and significant decrease in 22 and 36 kDa proteins. Pathogenesis related PR-18 was specific in leaves at 250 μM JA and PR-21 have cross reacted differently with 21 and 30 kDa proteins in leaves and roots treated by all JA concentrations. Further, the immunoblot analysis with glutamine synthetase, GS-45 antibodies revealed a specific cross reaction with 45 and 47 kDa proteins of both control and JA treated leaves, however, higher at 100 and 250 μM JA treated leaves than control ones. Further, the malondialdehyde (MDA) content significantly increased in leaves and roots treated with JA, indicated membrane damage with JA treatments that led to the generation of peroxidation products. The peroxidase isozymic pattern showed two specific isoforms. Besides, the activities of SOD and catalase were significantly elevated in JA treated leaves.

The plants of pigeonpea (Cajanus cajan L.) cv. H77-216 were subjected to moderate [soil moisture content (SMC) = 7.3 ± 0.5 %] and severe (SMC = 4.3 ± 0.5 %) drought by withholding the irrigation at vegetative stage (45 d after sowing). The control plants were maintained at SMC of 11.0 ± 0.5 %. Half of the stressed plants were re-irrigated and their recovery was studied after 2 d. Leaf water potential, osmotic potential, and relative water content of leaf and root decreased significantly while a sharp rise in proline and total soluble sugars contents were noticed. Drought induced a significant increase in 1-aminocyclopropane 1-carboxylic acid (ACC) content and ACC oxidase activity which caused a considerable increase in ethylene evolution. Malondialdehyde content and relative stress injury were increased under drought whereas reverse was true for ascorbic acid content. The membrane integrity of roots decreased during stress and recovered on rehydration. The specific activity of total superoxide dismutase, ascorbate peroxidase, glutathione reductase, and glutathione transferase decreased to 37 - 78 %, 17 - 62 %, 29 - 36 % and 57 - 79 % at moderate and severe drought, respectively. The increase in activity of catalase and peroxidase could not overcome the accumulation of H₂O₂ content in the roots.

The genetic variability in the seed proteins and the enzyme alcohol dehydrogenase (ADH) in representative species of the genus Cucurbita was studied. The banding patterns were obtained by means of vertical block electrophoresis in polyacrylamide gel. A specific protein components and ADH isoenzymes were established in the polymorphic banding patterns which can be applied individually or in combination as potential biochemical markers for breeding purposes.

Effects of temperature (15/10, 25/20, 30/25, and 35/30 °C) and drought stresses on the expression of granule-bound starch synthase I (GBSSI) gene were examined in rice (Oryza sativa L.) seedlings. The GBSSI expression was higher at the low temperature (15/10 °C), and the transcript level decreased at temperatures higher than 30 °C. Protein phosphorylation was involved in the low temperature-stimulated signal transduction of GBSSI regulation. The expression of GBSSI in rice seedling was reduced under a drought stress. Even though exogenous ABA played a role to reduce the GBSSI transcript accumulation under non-stress condition, the reducing of GBSSI expression by drought stress appeared to be mediated by an ABA-independent pathway.

Effect of two Ni concentrations (10 and 200 μM) on growth, Ni accumulation, chlorophyll and proline contents, relative water content (RWC) as well as the activities of superoxide dismutase (SOD), catalase (CAT), peroxidase (POD) and glutathione S-transferase (GST) were studied in shoots of wheat plants. Treatments caused a considerable accumulation of Ni in the shoots. However, exposure of plants to 10 μM Ni did not lead to significant alterations in shoot growth except for a slight increase in fresh mass. The other parameters studied were not affected by treatment of plants with 10 μM Ni. In contrast, 200 μM Ni caused inhibition of shoot growth, a decline in RWC and chlorophyll content, accumulation of proline and occurrence of visible symptoms of Ni toxicity. The activities of SOD and CAT decreased in response to 200 μM Ni. Conversely, several-fold enhancements of POD and GST activities were observed following the 3^rd day of 200 μM Ni treatment.

Explants taken from the mature vigorous tree of wild cherry (Prunus avium L.) were assayed for their organogenic capacity under various phytohormonal treatments. The highest rate of adventitious shoot multiplication was recorded at a combination of 0.5 mg dm^-3 6-benzylaminopurine (BAP) and 0.05 mg dm^-3 thidiazuron (6.83 shoots per explant). No differences in multiplication rates were found among media supplemented with BAP, BAP + α-naphthaleneacetic acid (NAA) or BAP + indole-3-butyric acid (IBA). Shoot elongation was significantly affected by the concentration of BAP, regardless of auxin addition to medium. Up to 73 % of microshoots rooted after using 0.3 mg dm^-3 IBA, otherwise the adventitious rooting occurred at reasonable frequencies in all auxin treatments. Regenerated plantlets were successfully hardened ex vitro and continued to grow after the transfer to soil. No morphological aberrations were observed in the regenerates.

Following drought stress at supraoptimal temperature the increase in proline (Pro) content in transgenic (T) soybean [Glycine max (L.) Merr. cv. Ibis] plants overexpressing the gene coding for the last enzyme of Pro biosynthesis, L-Δ¹-pyrroline-5-carboxylate reductase, was much greater than in wild type (W) plants (105-fold versus 19-fold after 7 d). Under control conditions arginine accounted for nearly 60 % of the total free amino acid content. After stress treatment the content of Pro was more than 50 % in both T and W genotypes, and at the end of recovery the γ-aminobutyrate content reached 27 and 53 % in the W and T plants, respectively. Without stress treatment there was only a 2-fold difference between T and W in the tyrosine content. However, during the stress period and the subsequent recovery a similar difference was found for many amino acids. The present results indicate that manipulating of the content of a single amino acid influences the whole free amino acid composition in soybean.

Telomere-binding proteins have recently been recognised not only as necessary building blocks of telomere structure, but namely as components which are of central importance to telomere metabolism being involved in regulation of telomere length as well as in protective (capping) function of telomeres. Although the knowledge on plant telomeric DNA-binding proteins lags behind that in human and yeast, recent data show both analogies and plant-specific features in the composition and interactions of telomeric proteins. This review focuses primarily on proteins with known amino acid sequence. These can be classified into following groups: 1) the family of proteins with Myb domain at C-terminus, 2) proteins with Myb domain at N-terminus, both binding double-stranded DNA of telomeric repeats TTTAGGG, 3) the single-stranded DNA-binding proteins, and 4) other proteins that act also in non-telomeric chromatin regions. Proteins with C-terminal Myb domain reported as IBP family were previously found in human, whereas Smh family representing proteins with Myb domain at N-terminus was identified only in plants. Also RRM family of the single-stranded DNA-binding proteins is likely to be plant specific.

In vitro organogenesis was achieved from callus derived from hypocotyl explants of Cucumis sativus L. cv. Poinsett 76. Calli were induced from hypocotyl explants excised from 7-d-old seedlings grown on Murashige and Skoog (MS) medium containing 87.64 µM sucrose, 0.8 % agar, 3.62 µM 2,4-dichlorophenoxy acetic acid and 2.22 µM 6-benzyladenine (BA). Regeneration of adventitious buds from callus (25 shoots explant^-1) was achieved on MS medium supplemented with 8.88 µM BA, 2.5 µM zeatin and 10 % coconut water after two subcultures in the same medium at 30-d interval. Gibberellic acid (1.75 µM) favoured shoot elongation and indole 3-butyric acid (7.36 µM) induced rooting. Rooted plants were hardened and successfully established in soil.

Ferredoxin-dependent glutamate synthase (Fd-Gogat; EC 1.4.7.1) in leaf and root plastids is the last enzyme involved in the pathway of nitrate assimilation in higher plants. Arabidopsis thaliana expresses two different genes: the first, light regulated, specific of green tissues and the second expressed in other tissues. In this work, we investigated whether in our clone, OsGog2 AC Y12595, this gene is up-regulated by light or it is expressed under darkness. Fd-Gogat specific activity, protein and mRNA increased after light treatment in rice shoots. In roots, the activity and the protein content remained constant, whereas the mRNA is repressed by light treatment. The results obtained using a specific probe, situated in the 3' untranslated region of the OsGog2 cDNA, indicated that OsGog2 gene is up-regulated by light and that its expression is tissue specific and suggested that a dark expressed Fd-Gogat gene could be present in rice similarly as in Arabidopsis.

In roots of Pisum sativum seedlings, the average lag-time required for initiation of the gravitropic response was reduced proportionally to the concentration of 24-epibrassinolide (EBL) added to the root solution (range of 10^-13 to 10^-8 M concentrations). A treatment with clotrimazole, a compound inhibiting steroid synthesis, prevents initiation of the gravitropic response. This effect was partly reverted by addition of EBL. From analysis of variability in the populations, it is suggested that BR conditions the root curvature through a gravitropic-induced change in sensitivity to the PGRs regulating cell elongation.

Susceptibility of Mexican cacti to Agrobacterium rhizogenes was evaluated in 65 species of 22 genera. Stem discs taken from in vitro cultured plants were inoculated with Agrobacterium rhizogenes A4 agropine-type strain that contains the wild RiA4 plasmid and the binary vector pESC4 with the nptII and gus genes. Hairy roots were produced directly from wounds, or starting from calli generated on the wounded surface, in 34 of the evaluated species. The frequency of hairy roots formation, the number of roots per explant and its growth rates were variable among the tested species. In the 31 remaining species the production of transformed roots was not observed under the conditions used in these experiments. Histochemical detection of β-glucuronidase (GUS) activity demonstrated the expression of this foreign gene in the hairy roots. PCR analyses demonstrated the presence of the rolB and nptII genes in the DNA of the transformed roots. The patterns of alkaloid-like compounds obtained by thin layer chromatography in some of the tested species were qualitatively similar between the transformed and non-transformed roots.

This experiment is designed to determine the most suitable conditions and media for propagating three selected fig (Ficus carica L.) clones through tissue culture. The clone 37 displayed a higher performance than clones 50 and 82. As the multiplication medium, the Murashige and Skoog (MS) medium containing 1 mg dm^-3 α-indole-3-butyric acid (IBA), 1 mg dm^-3 gibberellic acid and 5 mg dm^-3 6-benzyladenine were the best, whereas, MS medium complemented with 1.2 and 2.5 μM IBA or 1-naphthalene acetic acid (NAA) were better in respect to rooting. Peat followed by volcanic tuff gave the best performance for acclimatization to outdoor conditions.

A protocol is established for regeneration of the economically important cut flower plant, Gypsophila paniculata L., using shoot tips explants. Multiple shoots were obtained on Murashige and Skoog medium fortified with 0.5 mg dm^-3 each of α-naphthaleneacetic acid and 6-benzyladenine. Addition of 10 g dm^-3 agar promoted shoot proliferation and reduced the degree of shoot vitrification. Transfer to 3 mg dm^-3 indole^-3-butyric acid containing medium produced optimum root initiation and development. The produced plants as well as intact plants were subjected to the random amplified polymorphic DNA (RAPD) analysis. Using 9 primers, the total number of amplification products generated by polymerase chain reaction was 142 bands (15.7 bands per primer), of which 7.74 % showed polymorphism. The analysis of bands recorded, showed 92.25 % similarity. The results indicated that very low variation at the DNA level occurred during in vitro culture of Gypsophila.

The effect of short-term exposure to elevated CO₂ concentration and high irradiance on the activity of superoxide dismutase (SOD), ascorbate peroxidase (APX), guaiacol peroxidases (GPX) and catalase (CAT), and on the extent of the lipid peroxidation was studied in bean (Phaseolus vulgaris L.) plants. Plants were exposed for 4 d (8 h a day) to irradiance of 100 (LI) or 1000 (HI) μmol m^-2 s^-1 at ambient (CA, 350 μmol mol^-1) or elevated (CE, 1300 μmol mol^-1) CO₂ concentration. Four-day exposure to CE increased the leaf dry mass in HI plants and RuBPC activity and chlorophyll content in LI plants. Total soluble protein content, leaf dry matter and RuBPC activity were higher in HI than in LI plants, although the HI and CE increased the contents of malonyldialdehyde and H₂O₂. Under CA, exposure to HI increased the activity of APX and decreased the total SOD activity. Under CE, HI treatment also activated APX and led to reduction of both, SOD and GPX, enzymes activities. CE considerably reduced the CAT activity at both irradiances, possibly due to suppressed rate of photorespiration under CE conditions.

Rice (Oryza sativa L.) was grown in pots with pyridine N-oxide (PNO), 4-morpholino pyridine N-oxide (MNO), and sodium meta silicate as the sources for silicon. Aliquots of these were added in fortnightly intervals to seedlings through anthesis stage. The plants were monitored for plant growth characteristics, chlorophyll content (SPAD values), photosystem 2 activity (variable to maximum fluorescence ratio of dark adapted leaves), and for blast and yellow stem borer resistance. Deposition of silica in the leaves was monitored by scanning electron microscopy and silicon mapping. PNO or MNO application resulted in significant silicon accumulation in leaf bundle sheath cells. Application of PNO and MNO imparted disease and pest resistance by increasing silicon uptake of rice plants.

The effects of sodium nitroprusside (SNP; nitric oxide donor) treatment on drought stress induced by PEG for different periods of time in wheat seedlings were investigated. Our results suggested that treatment for 2, 4 and 6 d with 15 % PEG could be termed as mild, moderate and severe stress, respectively. Drought stress induced accumulation of hydrogen peroxide and resulted in lipid peroxidation. On the other hand, activities of SOD, CAT and PAL increased under mild stress to counteract the oxidative injury and then decreased when the stress became severe (6 d). As the effect of SNP treatment, 0.2 mM enhanced wheat seedlings growth and kept high relative water content and alleviated the oxidative damage. However, 2 mM SNP aggravated the stress as a result of uncontrolled generation of reactive oxygen species and ineffectiveness of antioxidant systems.

A screening for the enzyme L-myo-inositol-1-phosphate synthase [EC 5.5.1.4] has been made first time in both vegetative and reproductive parts of the representative members of pteridophytes: Lycopodium, Selaginella, Equisetum, Polypodium, Dryopteris, and Gleichenia. The enzyme has been partially purified following low-speed centrifugation, streptomycin sulphate precipitation, ammonium sulphate fractionation, chromatography on DEAE-cellulose and gel-filtration through Sephadex G-200, and characterised from the reproductive pinnules of Gleichenia glauca Smith. The enzyme has a pH optimum at 7.5. The K_m for glucose-6-P and NAD⁺ were 0.922 × 10^-3 M and 0.9 × 10^-4 M, respectively. A basal activity of the enzyme has been recorded in absence of exogenous NAD⁺. The enzyme activity was augmented with NH₄Cl, but heavy metals like Hg²⁺, Cu²⁺ and Zn²⁺ inactivated it.

The relation between oxygen evolution rate (OER) and quantum yield of photochemical reactions in photosystem 2 (Φ_PS2) was examined in lichen symbiotic alga Trebouxia erici Ahmadjian (strain UTEX 911) exposed to different irradiances and osmotic stress (2 M sucrose for 60 h). Linear relationship was found between OER and Φ_PS2 in control cell suspension within irradiance range of 0 - 500 μmol m^-2 s^-1. Under osmotic stress, OER and Φ_PS2 were significantly reduced. Relation between OER and Φ_PS2 was curvilinear due to strong osmotically-induced inhibition of OER at high irradiance. The highest used irradiance (500 μmol m^-2 s^-1) was photoinhibitory for osmotically-stressed T. erici because non-photochemical quenching (NPQ) increased substantially. Energy-dependent quenching represented major part of NPQ increase. Osmotic stress led also to the reduction of capacity of photochemical processes in PS 2 (F_V/F_M) and increase in F₀/F_M. These changes indicated negative effects of osmoticum on structure and function of photosynthetic apparatus.

Glass microelectrodes were inserted into Dionaea muscipula (Venus flytrap) lobes and the action potentials (APs) were recorded in response to a sudden temperature drop or a direct current (DC) application. The effect of potassium channel inhibitor, tetraethylammonium ion, was the lengthening of the depolarization phase of AP. APs were also affected by the anion channel inhibitor, anthracene-9-carboxylic acid, that made them slower and smaller. Neomycin, which disturbs inositol triphosphate-dependent Ca²⁺ release, caused the visible inhibition of AP, too. Ruthenium red, which blocks cyclic ADP-ribose-dependent Ca²⁺ release, totally inhibited DC-triggered APs and induced the decrease in the amplitudes of cold-evoked APs. Lanthanum ions significantly inhibited both cold- and DC-induced membrane potential changes. It was concluded that during excitation Dionaea muscipula relied upon the calcium influxes from both the extra- and intracellular compartments.

The in vitro response of two Prunus rootstocks: GF 677 (Prunus persica × Prunus amygdalus), and Nemared (Prunus persica) to increasing concentrations of KCl of the culture medium was studied. Shoots were grown in vitro for 8 weeks on an Murashige and Skoog medium supplemented with 0, 5, 10, 15, 20, 40 or 80 mM KCl. By increasing KCl concentration from 0 to 40 mM, the number of shoots per explant was not significantly affected for both rootstocks. However, Nemared rootstock formed more shoots per explant than GF 677 under respective KCl concentrations of the medium. Inclusion of 80 mM KCl in the medium resulted in a reduction of growth of both rootstocks. Sodium, Fe, Mn, and Zn concentration in tissues of Nemared rootstock were significantly higher than the respective values of GF 677.

The present work was focused on abscisic acid (ABA) changes in three differently coloured petunias during flower development and senescence. The ABA content was studied in correlation with changes of flower pigments and other phytohormones. The variations of anthocyanins and endogenous hormones were induced by treatments with 1 or 2 mM amino-oxyacetic acid (AOA), 50, 100 μM thidiazuron (TDZ) and 50 μM 6-benzyladenine (BA). ABA content decreased during bud development and increased during senescence. The AOA reduced the anthocyanins content and avoided ABA increase, while the cytokinins (BA and TDZ) did not significantly affected anthocyanin contents but increased ABA content. TDZ doubled the ABA content compared to the control. However, the treatments did not affected flower life, confirming the secondary role of ABA during flower senescence.