The nodal explants of in vitro shoots of Holarrhena antidysenterica L. were cultured on Murashige and Skoog's (MS) medium augmented with 15 μM N⁶-benzyladenine (BA) alone (control) or supplemented with different concentrations (1, 5, 10 and 20 mg dm^-3) of CdCl₂, CuSO₄, Pb(NO₃)₂ and ZnSO₄. The maximum morphogenic response in terms of average shoot number (4.95 ± 0.17) was seen in control. ZnSO₄ proved to be less inhibitory in comparison to CuSO₄, Pb(NO₃)₂ and CdCl₂. None of the explants cultured on CdCl₂ containing medium induced multiple shoots. Maximum protein content [3.80 ± 0.04 mg g^-1(f.m.)] was observed in control and slightly less [3.50 ± 0.02 mg g^-1(f.m.)] in tissues exposed to 1 mg dm^-3 of CuSO₄ and minimum [1.00 ± 0.02 mg g^-1(f.m.)] in Zn treated (20 mg dm^-3) explants. SDS-PAGE analysis of the treated tissues revealed that two new polypeptides (29 and 20 kDa) in response to Cu and Zn treatment, respectively, have been synthesized.

Maize catalase (CAT) mutants lacking in CAT isozymes were used to investigate the response of CAT and superoxide dismutase (SOD) to norflurazon (NF) caused oxidative stress in 18-d post-pollination scutella. NF treatment caused an increase in malonyldialdehyde content, which is an indicator of oxidative stress, and a decrease in a content of photoprotectant carotenoids in the scutella. CAT activity decreased greatly with increasing NF concentration in standard maize line (W64A) and CAT-2 null mutant (WA10C), however, it remained relatively constant in CAT-2/CAT-3 double null mutant (WDN10). Cat1 transcript increased in the NF-treated scutella of W64A and WDN10, with a greater Cat1 transcript in WDN10, whereas Cat2 transcript decreased in the NF-treated scutella of all lines examined. In all lines, SOD activities were not changed noticeably at various NF concentrations. In the scutella of W64A, Sod4A decreased in response to NF but the other Sod transcript contents were unchanged. The CAT-deficient mutants reacted with raised transcripts of Sod1, Sod3, Sod4 or Sod4A.

The shoot fresh mass, root length and root numbers of two potato (Solanum tuberosum L.) cultivars Favorita and Helanwuhua were increased significantly by the application of 0.2 - 2 mg dm^-3 jasmonic acid (JA) in the Murashige and Skoog medium. However, the growth of potato explants was inhibited by JA at high concentrations (20 - 50 mg dm^-3). Chlorophyll content in explant leaves decreased with an increase in the concentration of JA. In leaves treated with 0.2 mg dm^-3 JA acid peroxidase activity increased, while in the leaves treated with more than 2 mg dm^-3 JA peroxidase activity decreased. Under the dark, the microtuber numbers, fresh mass and percentage of big microtubers of two potato cultivars were not promoted by the application of 0.2 - 50 mg dm^-3 JA.

5-enolpyruvylshikimate 3-phosphate synthase (EPSPS; 3-phosphoshikimate 1-carboxyvinyl-transferase; EC 2.5.1.19) is a critical enzyme in the shikimate pathway. The full-length EPSPS cDNA sequence (CaEPSPS, GenBank accession number: AY639815) was cloned and characterized for the first time from woody plant, Camptotheca acuminata, using rapid amplification of cDNA ends (RACE) technique. The full-length cDNA of CaEPSPS was 1778 bp containing a 1557 bp ORF (open reading frame) encoding a polypeptide of 519 amino acids with a calculated molecular mass of 55.6 kDa and an isoelectric point of 8.22. Comparative and bioinformatic analyses revealed that CaEPSPS showed extensive homology with EPSPSs from other plant species. CaEPSPS contained two highly conserved motifs owned by plant and most bacteria EPSPSs in its N-terminal region. Phylogenetic analysis revealed that CaEPSPS belonged to dicotyledonous plant EPSPS group. Tissue expression pattern analysis indicated that CaEPSPS was constitutively expressed in leaves, stems and roots, with the lower expression being found in roots. The coding sequence of CaEPSPS gene was successfully subcloned in a plasmid-Escherichia coli system (pET-32a), and the cells containing the plasmid carrying the CaEPSPS gene exhibited enhanced tolerance to herbicide glyphosate, compared to the control.

The variability of the Strawberry vein banding virus (SVBV) isolates was investigated. In total 267 strawberry plants from 6 European countries and North America were tested for the presence of SVBV. Only 4 plants were positive. Partial genomic sequences of the capsid protein gene of three North American SVBV isolates were determined. Only minor sequence variability (0.7 %) was observed during a comparison with existing nucleotide data of the European and the North American isolates (9 isolates). No variability at all could be found in the annealing regions of primers and probes used for molecular detection of SVBV for these isolates. However, a comparison to a sequence of a Chinese isolate published recently revealed a much higher DNA sequence difference (9.5 %) of this isolate.

The photosynthetic and growth characteristics of Mosla hangchowensis, an endangered species and M. dianthera, a weed, were compared under three irradiances (PPFD) similar to shaded forest understory, forest edge and open land. Both species grown at lower PPFD had lower PPFD-saturated photosynthetic rate (P_max), saturation PPFD, compensation PPFD, apparent quantum yield, total mass and root/shoot ratio and higher specific leaf area, leaf area ratio and height ratio. At the same PPFD treatment, however, specific leaf area and leaf area ratio of M. hangchowensis were higher than those of M. dianthera, other above parameters were lower than those of M. dianthera. Water use efficiency did not differ between M. hangchowensis and M. dianthera, but it reached its maximum at 70 % of full PPFD. These results suggested the optimum habitat of M. hangchowensis is the forest edge.

Studies were undertaken to identify genetic relationships in three species of Typhonium and to evaluate the genetic variance within populations of Typhonium trilobatum, Typhonium roxburghii and Typhonium flagelliforme by using random amplified polymorphic DNA (RAPD) markers. A total of 193 distinct DNA fragments ranging from 0.2 to 3.2 kb, were amplified using 22 selected random decamer primers. The cluster analysis indicated that the three species of Typhonium formed two clusters: the first one consisted of T. trilobatum and T. roxburghii, the second one was represented by T. flagelliforme. A maximum similarity of 63 % was observed in T. trilobatum and T. roxburghii. T. flagelliforme shared up to 43 % similarity with T. trilobatum and T. roxburghii. The closest genetic distance was obtained within populations of different Typhonium species.

Wild-type and the handshake (has) mutants in Arabidopsis thaliana were analyzed. Compared to the wild-type, has mutants display a number of morphological alterations, which can largely be traced back to altered meristem function. Analyses of apical meristem of mutant plants showed that mutation affected meristem structure and patterns of STM expression.

Time-lapse monitoring using infrared imaging revealed a distinct change in circumnutatory behaviour of Arabidopsis inflorescence stems by dark treatment, which drastically increased curvature and decreased nutation frequency. Re-irradiation during dark treatment had different effect on the nutation frequency and the curvature, suggesting that radiation condition controls them through different mechanism.

The scale segments of the bulblets of Hyacinthus orientalis L. cv. Anna Marie were examined to improve their growth and development with cold-pretreatment and sucrose. The cold-pretreated (4 °C for 4 months) segments showed higher growth and better development of the bulblets on medium without sucrose than ones stored at 20 °C. A rapid decrease in starch content of bulb pieces was found during the first 2 weeks in all cultures and thereafter the content decreased gradually. A scanning electron microscopic observation during the bulblet growth and development showed a gradual decreasing trend of the starch granules from 2 to 16 weeks of the cultures. SDS-PAGE electrophoresis revealed the presence of a characteristic polypeptide of approximately 45 kD, which is assumed to be a major storage protein in the bulblets.

The effect of thidiazuron (TDZ) was studied on in vitro axillary shoot proliferation from nodal explant of Psoralea corylifolia - an endangered medicinal plant. Proliferation of shoots was achieved on Murashige and Skoog (MS) medium supplemented with 0.5, 1, 2, 3, 4 and 5 μM TDZ. The maximum number (13.6 ± 1.4) of shoots per explant were obtained from nodal segment cultured on 2 μM TDZ for 4 weeks and this increased to 29.7 ± 2.1 on hormone free MS medium after 8 weeks. The in vitro proliferated and elongated shoots were transferred individually on a root induction medium containing 0.5 μM indole-3-butyric acid (IBA) and within 4 weeks 4.5 ± 0.5 roots per shoot were produced. The regenerated plantlets were transferred to 1:1 soil and vermiculite mixture and acclimatized with 80 % survival rate. Fully acclimatized plants were grown in garden soil in greenhouse and their morphological and physiological parameters were comparable with seedlings.

Hairy roots of Rhamnus fallax Boiss. were induced using Agrobacterium rhizogenes strain A4M70GUS. The culture established on Woody plant media (WPM) showed a typical hairy root phenotype: rapid growth, reduced apical dominance and root plagiotropism. Seven clones of R. fallax were selected on the basis of their differences in colour and the root branching. The growth of hairy root culture, measured through gain in fresh mass, was done under 16-h photoperiod or in the dark. An increase in anthraquinone (AQ) content was obtained in clones with yellow and less branched roots, like clone 1 [16.43 mg g^-1(d.m.)] and clone 7 [14.21 mg g^-1(d.m.)], compared with other analysed transformed and non-transformed tissue. This study presents the first report of successful transformation of any species from family Rhamnaceae by A. rhizogenes and analysis of AQ production in transformed tissue.

Negative effects of osmotically-induced dehydration of two foliose lichen species, Lasallia pustulata and Umbilicaria hirsuta, was studied at physiological (22 °C), low (5 °C) and freezing temperature (-10 °C), using chlorophyll (Chl) fluorescence. In both species, exposure to increasing sucrose concentrations led to a pronounced decrease in potential (F_V/F_M), and actual (Φ₂) quantum yields of photochemical processes in photosystem 2. L. pustulata was more sensitive to osmotic stress, because comparable osmotic dehydration inhibited F_V/F_M and Φ₂ more than in U. hirsuta. Critical concentration of sucrose that fully inhibited photochemical processes of photosynthesis was 2.5 M, which represented water potential (Ψ_w) of -18.8 MPa. Decrease in background Chl fluorescence (F₀) and increase in non-photochemical quenching (qN) revealed two phases of osmotic stress in lichens: phase I with no change (Ψ_w 0 to -6.6 MPa) and phase II (Ψ_w -11.3 to -18.8 MPa) typical by substantial change in Chl fluorescence parameters. Effects of thallus anatomy on species-specific response to osmotic dehydration is discussed and attributed to the results obtained by optical microscopy and Chl fluorescence imaging technique.

The effects of NaCl and ABA on the respiration of N₂-fixing nodules were analysed in common bean (Phaseolus vulgaris) inoculated with Rhizobium tropici the reference strain CIAT899. Shoot and nodule growth was more inhibited by NaCl than root growth. The O₂ uptake by nodulated roots at 21 kPa O₂ was significantly inhibited by salinity. Raising pO₂ stimulated nodule respiration more under NaCl treatment than for the control, although it did not compensate totally for the inhibitory effect of NaCl. Short NaCl application was less destructive than long term application. Also, the external application of ABA inhibited nodule respiration, and this inhibition was partly compensated by raising pO₂.

The effects of boron and NaCl induced salinity on growth and mineral composition of the pear (Pyrus communis L.) rootstock OH × F 333 shoots cultured in vitro were investigated. Shoots were grown in vitro for seven weeks on a Murashige and Skoog medium containing two B concentrations (0.1 and 2 mM) combined with five NaCl concentrations (0, 10, 20, 40, and 80 mM). The longest shoots were produced at 0.1 mM B and 80 mM NaCl, but highest number of shoots were produced at 0.1 mM B and 0-20 mM NaCl. Inclusion of 20 and 40 mM NaCl in the culture medium significantly increased fresh mass of cultures compared to 0 mM NaCl for all B concentrations tested. The concentrations of P, K, Ca, Mg, Na, Fe, Mn and Zn of plants were affected by B and NaCl concentration of the medium.

The study presents the comparative analyses of endogenous contents of auxin (IAA), cytokinins (CKs), polyamines (PAs), and phenolic acids (PhAs) in apical and basal parts of elm multiplicated shoots with regard to the organogenic potential. The shoot-forming capacity was higher in the apical part than in the basal part. However, the timing of root formation was in the apical type of explant significantly delayed (compared with the organogenic potential of basal part). Significantly higher contents of free bases, ribosides and ribotides of isopentenyl adenine, zeatin and dihydrozeatin that were found in the apical segments, might be considered as the most important factor affecting in vitro shoot formation. The content of endogenous free IAA was approximately three times higher in the basal shoot parts than in the apical parts. The amounts of putrescine and spermidine were higher in the apical part which generally contains less differentiated tissues than the basal part of shoot. The predominant PhA in both types of explants was caffeic acid, and concentrations of other PhAs decreased in the following order: p-coumaric, ferulic, sinapic, vanillic, chlorogenic, p-hydroxybenzoic and gallic acids. The contents of all determined PhAs in their free forms and higher contents of glycoside-bound p-coumaric, ferulic and sinapic acids, precursors for lignin biosynthesis, were found in the basal parts.

Oncidium cultivars gave different embryogenic responses of leaf explants when affected by auxins (2,4-D, IAA, IBA and NAA), cytokinins (2iP, BA, kinetin, TDZ and zeatin), sucrose, NaH₂PO₄, casein hydrolysate, peptone, and glutamine. The best embryogenic responses of cv. Sweet Sugar were at 20 g dm^-3 sucrose, 85 mg dm^-3 NaH₂PO₄ and 3 mg dm^-3 kinetin, respectively. The development of somatic embryos on leaf explants of cv. Sweet Sugar was delayed for about 10 - 20 d in comparison with cv. Gower Ramsey. On growth regulator-free medium, about 40 % of leaf derived embryos of cv. Gower Ramsey were fused together in their basal parts and so called multiple-state embryos. However, under the same condition, the embryos of cv. Sweet Sugar were all in multiple-state form.

The in vitro rooting of myrtle (Myrtus communis L.) plantlets was performed in containers with gas permeable (V) and non-permeable (C) closures characterized by a different number of gas exchanges (1.4 and 0.3 h^{- 1}, respectively). The rooting was induced on Perlite, soaked with half strength Murashige and Skoog (MS) medium with 0.5 mg dm^-3 IBA, either with and without 15 g dm^-3 of sucrose. During the rooting phase, it was demonstrated that C cultures without sucrose (C-) negatively affect the growth of myrtle plantlets. The net photosynthetic rate and the starch content showed the lowest values in C cultures with and without sucrose (C+ and C-) while chlorophyll a content did not vary among treatments, therefore it could not be considered an indicative parameter to evaluate the autotrophic metabolism in myrtle plantlets. Electron microscopy and image analysis were employed to evaluate the leaf ultrastructure at three sample dates. Plantlet rooted in vented vessels with and without sucrose (V+ and V-) showed chloroplasts with numerous starch inclusions, while several osmiophilic plastoglobules (frequently related with leaf senescence) were found in chloroplast of leaf cells of C- myrtle plantlets.

Late blight of potato, caused by Phytophthora infestans was studied by using a resistant clone of potato on one side and a susceptible clone on the other side. A gene coding putatively for an α-galactosidase has been isolated by mRNA reverse transcription polymerase chain reaction differential display and was shown to be differentially expressed between the resistant and the susceptible clone. α-Galactosidases catalyse the hydrolysis of α-1,6 linked α-galactose residues from oligosaccharides and it could be shown in the present work that raffinose content decreases at 30 h after infection by P. infestans in the resistant clone.

A reproducible protocol has been developed for high frequency plant regeneration from immature embryos of Argyrolobium roseum Jaub & Spach, an important medicinal legume. Green nodular calli were initiated from immature embryos excised from 10-d-old pods in 70 % of cultures within 3 weeks when grown on Murashige and Skoog (MS) medium supplemented with 0.5 mg dm^-3 benzylaminopurine (BAP) + 0.25 mg dm^-3 indole-3-acetic acid (IAA). Subsequent transfer of 5 mm² callus pieces to MS medium supplemented with BAP (0.5 mg dm^-3) alone or in combination with IAA (0.25 mg dm^-3) facilitated regeneration of multiple shoots. Organogenic calli bearing multiple shoots when transferred to MS medium supplemented with BAP (0.5 mg dm^-3) + IAA (0.25 mg dm^-3) supported rapid shoot elongation. Shoot propagules subcultured to Gamborg's medium (B5) with 0.5 mg dm^-3 indole-3-butyric acid (IBA) rooted with 80 % frequency and developed into phenotypically normal plants. Plantlets were successfully acclimatized in a sterile mixture of sand and garden soil (1:1) under greenhouse and thereafter transferred to field beds.

The effects of NaCl on growth, contents of proteins and proline, and activities of catalase, peroxidase and polyphenol oxidase were investigated in seedlings and calli of Trigonella foenum-graecum L. and T. aphanoneura Rech. f. Seeds and hypocotyl explants were cultured on Murashige and Skoog medium supplemented with 0, 50, 100, 150 and 200 mM NaCl. Seed germination and the fresh and dry mass of the seedlings decreased significantly under salinity. In both species significant increases in protein content of seedlings over that of control were observed at 150 and 200 mM NaCl. Protein content in calli decreased at 200 mM NaCl over that of control. Protein content was higher in seedlings than in calli at all NaCl concentrations. Conversely, proline content was lower in seedlings than in calli at all the tested NaCl concentrations. NaCl caused changes in the activities of peroxidase, catalase and polyphenol oxidase in seedlings and calli.

The inoculation of the seedling roots of the resistant (Bousthami Noir) and susceptible (Jihel) date palm (Phoenix dactylifera) cultivars by Fusarium oxysporum f. sp. albedinis induced an increase in phenylalanine ammonia-lyase (PAL) activity. The response of the PAL activity in the resistant cultivar was faster and higher than in the susceptible one. However, the elicitation of the seedlings with the hyphal wall elicitor (HWE) of the pathogen induced identical PAL activity in both cultivars. In the resistant cultivar, the the PAL activity elicited with the HWE was not influenced by the addition of the fungal culture filtrate (FCF) whereas it was suppressed in the susceptible cultivar. This FCF suppressor effect was dose-dependent, not influenced by sodium periodate, whereas it was strongly reduced by the heat (121 °C for 45 min) and pronase E. These results show that differential induction of the defence mechanisms in both cultivars was not related to differences in the induction of the PAL activity, but to the suppression of its elicitation in the susceptible cultivar.

The aim of this study was to investigate the protein alterations in the transgenic kiwifruit (Actinidia deliciosa) overexpressing a transcription factor gene, OSH1. Although transgenic plant with introduced OSH1 indicates suppression of gibberellin (GA)-20 oxidase activity, application of GA to transgenic kiwifruit could not completely recover plant morphology and protein profiles. Eleven proteins decreased in the transgenic kiwifruit detected by two-dimensional polyacrylamide gel electrophoresis showed homologies to kiwifruit hypothetical protein, osmotin I and photosynthesis related protein. These results suggest that introduction of an OSH1 into kiwifruit caused wide-range alterations at protein level and alterations of protein accumulation should be considered to evaluate the substantial equivalence of plants transformed by a transcription factor.

To determine whether the major influence of high salinity is caused by the osmotic component or by salinity-induced specific ion toxicity, we compared the effects of mannitol, sorbitol, NaCl and KCl (all in concentratuions corresponded to osmotic potential -1.0 MPa) on the antioxidant and anatomical responses of the apple rootstock MM 106 explants grown in the Murashige and Skoog (MS) medium. All the compounds had a significant influence on explant's mineral composition and reduced the leaf water content, whereas mannitol and salts decreased chlorophyll (Chl) content and increased proline content. Superoxide dismutase (SOD), peroxidase (POD) and non-enzymatic antioxidant activities as well as H₂O₂ content were increased in the leaves and stems. In addition, in the leaves of explants exposed to NaCl an additional Mn-SOD isoform was revealed, while specific POD isoforms were detected in the leaves and stems treated with NaCl or KCl. However, catalase activity was depressed in the salt-treated leaves. At the ultrastructural level, the NaCl-treated leaves had the thickest lamina, due to an extensive increase of the size of epidermal and mesophyll cells. Also, an increase of the relative volume of the intercellular spaces in response to NaCl was observed. The results suggest that Na accumulation is the first candidate for the distinct antioxidant and anatomical responses between saline and osmotically generated stress in the MM 106 explants.

The effect of arsenic (32 - 96 µM) on the phosphorus content and Chl fluorescence was studied in soybean (Glycine max Merril) grown in the nutrient solution with and without phosphorus. The increased concentration of As led to the decrease in P content in plant organs. Parameters of Chl fluorescence of soybean leaves in the presence of these As concentrations did not show significant changes.

The biological activity of cell wall-derived galactoglucomannan oligosaccharides (GGMOs) was dependent on their chemical structure. Galactosyl side chains linked to the glucomanno-core influenced their inhibition of elongation growth of pea (Pisum sativum L. cv. Tyrkys) stem segments induced by 2,4-dichlorophenoxyacetic acid (2,4-D). Reduction of the number of galactosyl side chains in GGMOs caused stimulation of the endogenous growth. Modification on the glucomanno-reducing end did not affect significantly the activity of these oligosaccharides. GGMOs inhibited also the elongation induced by indole-3-acetic acid (IAA) and gibberellic acid (GA₃). In the presence of IAA the elongation growth was inhibited to 20 - 35 % after 24 h of incubation depending on GGMOs concentrations (1 μM, 10 nM, 0.1 nM), similarly as in the presence of 2,4-D, which confirms the hypothesis of GGMOs antiauxin properties. The elongation induced by GA₃ was inhibited to 25 - 60 %, however, the time course of inhibition was different compared with IAA and 2,4-D. The highest inhibition was determined already after 6 h of incubation with a significant decrease after this time. The results indicated a competition between GGMOs and growth regulators.

The aim of the present work was to evaluate oxidative stress and plant antioxidant system of three contrasting bean (Phaseolus vulgaris L.) genotypes in the response to drought. Drought was imposed 14 d after emergence, by withholding water, until leaf relative water content reached 65 %. Water stress increased lipid peroxidation (LPO), membrane injury index, H₂O₂ and OH^⋅ production in leaves of stressed plants. Activities of the antioxidative enzymes superoxide dismutase (SOD) and ascorbate peroxidase (APOX) increased significantly under water stress in all the studied cultivars, while catalase (CAT) increased in cvs. Plovdiv 10 and Prelom, but decreased in cv. Dobrudjanski ran. Furthermore cv. Plovdiv 10 which had the highest APOX and CAT activities also showed the lowest increase in H₂O₂ and OH^⋅ production and LPO while cv. Dobrudjanski ran showed the lowest increases (and often the lowest values) in the antioxidant enzyme activities and the highest increases of H₂O₂ and OH^⋅ production, and LPO. On the basis of the data obtained we could specify cv. Plovdiv 10 and cv. Prelom as drought tolerant and cv. Dobrudjanski ran as a drought sensitive.