A high frequency adventitious shoot regeneration protocol was developed for henbane (Hyoscyamus niger L.) using thidiazuron (TDZ). Hypocotyl, cotyledon and stem explants were cultured on Murashige and Skoog (MS) medium supplemented with different concentrations of N⁶-benzylaminopurine and TDZ. MS medium supplemented with 16 μM TDZ was the most effective for providing 100 % regeneration frequency associated with a 19.53 shoots per hypocotyl explant. Plantlets were rooted on MS medium supplemented with different concentrations of indole-3-butyric acid (IBA) and α-naphthaleneacetic acid. High rooting and survival was achieved using half strength MS medium supplemented with 8 μM IBA.

High efficiency shoot regeneration was achieved through leaflet and cotyledon derived calli in Cassia angustifolia - an important medicinal plant. Dark brown compact callus was induced at the cut ends of the explants on Murashige and Skoog's (MS) medium augmented with 1 µM N⁶-benzyladenine (BA) + 1 µM 2,4-dichlorophenoxyacetic acid (2,4-D). Such callus pieces on transfer to cytokinins (BA or kinetin) supplemented medium differentiated shoots within 10 - 15 d. Of the two cytokinins, 5 µM BA was optimum for eliciting morphogenic response in 83.33 and 70.83 % cultures with an average of 4.16 ± 0.47 and 3.70 ± 0.56 shoots in cotyledon and leaflet derived calli, respectively. The addition of 0.5 µM α-naphthaleneacetic acid (NAA) to MS + 5 µM BA further elevated the maximum average number of shoots to 12.08 ± 1.04 and 5.37 ± 0.52 for cotyledon and leaflet calli, respectively. The excised shoots were transferred to a rooting medium containing either IAA (indole-3-acetic acid), IBA (indole-3-butyric acid) or NAA. Nearly 95 % shoots developed an average of 5.4 ± 0.41 roots on half strength MS medium supplemented with 10 µM IBA.

The present study evaluated the effects of chilling, partial desiccation, cotyledon excision and successive subculture of microspore-derived embryos on plant development in oilseed rape (Brassica napus L.). The results showed that out of the five media, all the genotypes showed the best response when the embryos were cultured on the half-strength Murashige and Skoog medium with 2.0 mg dm^-3 benzylaminopurine. A cold treatment for 3 or 5 d further increased frequencies of embryo germination (90.0 %) and plantlet development (58.46 %). Desiccation for one day also increased the embryo germination and plantlet development in all genotypes tested. Cutting the cotyledons of the embryos at late cotyledonary stage significantly increased the frequency of plantlet development. The highest rate of plantlet development was obtained from cultures of embryos sampled with size of less than 4.0 mm. The successive subculture further improved the germination and development of plantlets from embryos. In the genotype ZJU452, the rate of plantlet development reached 99.78 % after the second subculture of embryos.

Plant regeneration through somatic embryogenesis of Areca catechu L. was established using leaf, root and stem segments as explants. Embryogenic callus was induced and maintained on medium supplemented with 2,4-dichlorophenoxyacetic acid (2,4-D) or 3,6-dichloro-2-methoxybenzoic acid (dicamba) at concentrations 2, 4, 6 and 8 mg dm^-3 in darkness. Somatic embryos were found on primary callus in the presence of 2 and 4 mg dm^-3 dicamba and during subculture on 2 - 8 mg dm^-3 2,4-D or 2 - 4 mg dm^-3 dicamba-containing media. Plantlet conversion from embryos was successfully achieved on growth regulator-free medium. The plants grew well when transplanted to containers in shaded greenhouse.

Efficient plant regeneration system from leaf base segments of wheat (Triticum aestivum L.) was developed. The factors affecting the callus formation and regeneration capacity of leaf segments of two genotypes; Bobwhite and Pavon 76, were investigated. The highest number of somatic embryos (SE) was obtained on Murashige and Skoog medium supplemented with 2 mg dm^-3 2,4-dichlorophenoxyacetic acid + 1 mg dm^-3 naphthalenacetic acid (14.7 SE per segment). Highest frequency of embryogenic callus (96 %) and somatic embryo formation (24.3 SE per segment) were achieved in the first segments. The highest plantlet regeneration was obtained after transfer of embryogenic calli to regeneration medium supplemented with 1 mg dm^-3 kinetin (6.3 plantlets per segment).

Experiments were carried out to evaluate the effects of 4/2 light-dark cycles (4 h of light followed by 2 h of dark) on the rooting responses of shoots cultivated in vitro of the fruit tree rootstocks GF 677 (peach × almond hybrid), Mr.S. 2/5 (Prunus cerasifera), MM 106 (apple Nothern Spy × Paradise M1) and BA 29 (Cydonia oblonga). Under this light regime rooting percentage of GF 677, Mr.S. 2/5 and MM 106 shoots reached 100 % as in the control treatment (16/8), while in BA 29 shoots, short light-dark cycles increased rooting response by about 65 %. Moreover, the shoots of all rootstocks submitted to the 4/2 cycle showed an appreciable increase in root number and length, and an earlier root emergence of about 4 - 5 d compared to the 16/8 cycle. Finally, rooting percentage of BA 29 shoots submitted to the 4/2 light regime and treated with 0.2 mg dm^-3 indolebutyric acid (IBA), was equal to that reported with 0.4 mg dm^-3 IBA under the 16/8 regime, indicating that the former light regime also amplified the rhizogenic effect of auxin.

Multiple shoot buds could be induced directly from internode explants of Celastrus paniculatus inoculated on Murashige and Skoog's (MS) medium containing different growth regulators. The best response was obtained when 4.44 μM 6-benzylaminopurine (BAP) was incorporated in the medium. Incorporation of indole-3-acetic acid (IAA) and α-naphthalene acetic acid (NAA) did not improve response, rather promoted callusing. Adventitious shoot buds could be multiplied and elongated on MS medium containing 2.22 μM BAP. Rooting of shoots (80 %) was obtained when their bases were dipped in pre-autoclaved indole-3-butyric acid (IBA) solution (2.45 mM) for 10 min followed by their implantation on medium containing 1/4 MS salts, 1.0 % sucrose and 0.6 % agar. Out of 500 plantlets subjected to hardening, 410 were successfully hardened under greenhouse conditions. Twenty plants were established in field while remaining of them were transferred to nursery conditions without any mortality.

Hydroponically grown cucumber plants were exposed to 14-d period of salinity (0, 50, 100 mM NaCl). NaCl caused reduction in the relative water content in the leaves. The Na⁺ content increased and the K⁺ content decreased. The net photosynthetic rate, stomatal conductance and transpiration rate were markedly decreased by all of the salt treatments. Salinity decreased also the maximum quantum efficiency of photosystem 2 (PS 2) determined as the variable to maximum fluorescence ratio, the photochemical quantum yield of PS 2 and the photochemical fluorescence quenching, while the non-photochemical quenching increased. Above results indicate that NaCl affects photosynthesis through both stomata closure and non-stomatal factors.

Supply of aqueous solution of triadimefon (20 mg dm^-3) to unstressed green gram plants increased the contents of soluble proteins, amino acids, nitrate and nitrite, and the activity of nitrate reductase in the leaves and nitrate reductase in nodules. The nitrogenase activity in nodules and roots was also increased. Number and fresh mass of nodules and their nitrate and nitrite contents were also higher than those of the controls. In contrast, the UV-B stress (12.2 kJ m^-2 d^-1) suppressed nodulation and nitrogen metabolism in leaves and roots compared to plants under natural UV-B (10 kJ m^-2 d^-1). Triadimefon-treated plants did not show such severe inhibitions after exposure to elevated UV-B. Thus triadimefon increased their tolerance to UV-B stress.

The effect of sucrose on fruiting, seed production, and seed germination of lesser centaury [Centaurium pulchellum (Sw.) Druce] was examined using explants of flowers and flower buds. Sucrose concentrations in the culture medium ranged from 0.003 to 0.3 M. It has been shown that the number of auxiliary buds, capsules dimension, number of viable seeds per capsule and seed dimensions increased with the increase of sucrose concentrations. The highest values were recorded at sucrose concentrations higher than 0.03 M, except for seeds size, which were larger at sucrose concentration ranging from 0.003 to 0.1 M. The germination of in vitro produced seeds was affected by previous culture history: a higher germination percentage was obtained in seeds that were raised from explants originally grown on medium with sucrose concentrations higher than 0.003 M.

Floral phenology, pollen quality and seed set of Plantago crassifolia plants, grown in the presence of increasing NaCl concentrations, were studied to test how this Mediterranean halophyte responded to salt stress during the reproductive phase of its life cycle. "Reproductive success" was maximal in plants grown in non-saline conditions, or in the presence of 100 mM NaCl, but it was negatively affected by higher salinities, due to a progressive reduction of pollen fertility, seed set, and seed viability.

Protoporphyrinogen oxidase (Protox) in the porphyrin pathway is the target site of the peroxidizing herbicides such as carfentrazone-ethyl and oxyfluorfen. In an attempt to develop herbicide-resistant plants, transgenic rice plants were generated via expression of herbicide-insensitive Bacillus subtilis Protox gene fused to the transit sequence for targeting to the plastid using Agrobacterium-mediated gene transformation. Homozygous transgenic rice lines of T₃ generation selected by hygromycin resistance test were examined if they are resistant to the herbicides carfentrazone-ethyl and oxyfluorfen. The homozygous transgenic lines had single copy insertion of B. subtilis Protox gene into their genomes and express its mRNA. Compared to wild-type rice, the transgenic lines were less susceptible to the herbicides when examined with respect to growth, electrolyte leakage, chlorophyll loss and lipid peroxidation. The in vitro Protox activities in transgenic lines were about 56 % higher than those in wild-type rice. With 10 µM concentration of the herbicides in the enzyme assays, Protox activities in transgenic lines were similar to those in non-inhibited wild-type rice. Less amount of protoporphyrin IX was accumulated in transgenic lines than in wild-type rice upon the treatment of the herbicides at 10 µM concentration. Our results indicated that expression of B. subtilis Protox gene was stably transmitted into T₃ rice plants and reduced their sensitivity to carfentrazone-ethyl and oxyfluorfen.

Sunflower seeds behaved as chilling and freezing sensitive and also exhibited acclimation under low seed moisture content (< 1 %). At high seed moisture content (approx. 22 %) they tolerated chilling stress but failed to acclimate under freezing temperatures. Pre-imbibitional chilling (5 °C) or freezing (-5 or -10 °C) stress significantly enhanced total soluble protein (TSP) content. Chilling treatment after imbibition (in contrast to pre-imbibition) enhanced germination and this was accompanied by increase in 30, 24 and 21.9 kDa TSPs content (3 d after germination). Freezing at -5 and -10 °C suppressed seed germination and increased content of 78 and 56.2 kDa wall bound proteins. Chilling acclimation decreased 35.4, 33.9, 29.5, 23.4 and 21.4 kDa TSPs.

Seeds of Cucurbita maxima, C. moschata and their interspecific hybrids were used to evaluate the intrapopulational and interpopulational variation of their protein composition. Three immunoprecipitating systems common to all the studied samples were detected by the Ouchterlony technique. Fourteen protein bands were identified by polyacrylamide gel electrophoresis (PAGE) whereas 23 bands were identified by sodiumdodecylsulfate (SDS)-PAGE. Using Western blotting (WB) also 23 bands were detected. The Jaccard's index of similarity calculated from SDS-PAGE and WB varied between 91 and 100 % for all the compared pairs of samples. These results demonstrate a high uniformity in the protein composition of all the samples and do not allow for their clear characterization.

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.

Potted two-year-old lemon trees [Citrus limon (L.) Burm. f.], cv. Verna grafted on sour orange (C. aurantium L.) rootstock, growing in greenhouse, were subjected to drought for 33 d. Control plants were daily irrigated at field capacity. Values of sap flow (SF) were compared with transpiration (E) rates measured gravimetrically. The results underlined the robustness and high sensitivity of the compensation heat-pulse technique for estimating transpiration on a wide range of SF. Good direct correlations between E and SF rates on an instantaneous and daily basis were obtained in both treatments. On a daily basis, a common calibration curve can be used for both irrigation treatments. On an instantaneous basis, changes in SF were matches by similar changes in E in both treatments, although the relationships between these parameters presented different intercepts in each treatment. Sap flow rates were influenced by weather conditions in trees growing in non-limiting soil water conditions. This makes it possible to evaluate the significance of any sap flow measurement in relation to the reference value calculated for the vapour pressure deficit at the time the measurement was taken.

The enzymatic properties of four chalcone synthase homologues CHS_H1, VPS, CHS 2 and CHS 4 from Humulus lupulus L. were investigated after heterologous expression in Escherichia coli. It was found that both VPS and CHS_H1 can utilize isovaleryl-CoA and isobutyryl-CoA as substrates producing compounds with positions in thin layer chromatography characteristic for phloroisovalerophenone and phloroisobutyrophenone. These reactions are accompanied by the formation of associated byproducts. The formation of naringenin chalcone can be catalyzed primarily by CHS_H1. Comparatively the ability of VPS to perform chalcone synthase reaction is very limited. Since only CHS_H1 has true chalcone synthase activity, this enzyme can be considered a key enzyme in prenylflavonoid biosynthesis. Both CHS 2 and CHS 4 utilize isovaleryl-CoA and isobutyryl-CoA as substrates, but the reactions were prematurely terminated. In comparison with VPS and CHS_H1, the optimum pH of CHS 2 was shifted to lower value. High expression of chalcone synthase-like genes were found in maturating hop cones of cultivars with high bitter acid content (Agnus, Magnum, Target) by Northern and Western blotting using probes specific for vps, chs_H1, chs 4 and polyspecific serum risen against recombinant protein CHS4, respectively. It was also found that these cultivars maintained expression of CHS homologues for a longer period of time during cone development in contrast to time-limited expression of CHS homologues in cultivars with low bitter acids content.

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.

Leaf morphology, longevity, and demography were examined in Quercus ilex and Phillyrea latifolia growing in a holm oak forest in Prades mountains (northeast Spain). Four plots (10 × 15 m) of this forest were submitted to an experimental drought during three years (soil moisture was reduced about 15 %). Leaf area, thickness and leaf mass per area ratio (LMA) were measured in sun and shade leaves of both species. Leaf longevity, the mean number of current-year shoots produced per previous-year shoot (Sn/Sn-1), the mean number of current-year leaves per previous-year shoot (Ln/Sn-1), and the percentage of previous-year shoots that developed new ones were measured once a year, just after leaf flushing. LMA and leaf thickness increased since leaf unfolding except in summer periods, when stomatal closure imposed low photosynthetic rates and leaves consumed their reserves. LMA, leaf area, and leaf thickness were higher in Q. ilex than in P. latifolia, but leaf density was higher in the latter species. Drought reduced the leaf thickness and the LMA of both species ca. 2.5 %. Drought also increased leaf shedding up to ca. 20 % in Phillyrea latifolia and decreased it up to ca. 20 % in Q. ilex. In the later species, Sn/Sn-1 decreased by 32 %, Ln/Sn-1 by 41 %, percentage of shoots developed new ones by 26 %, and leaf area by 17 %. Thus the decrease of leaf number and area was stronger in the less drought-resistant Q. ilex, which, under increasingly drier conditions, might lose its current competitive advantage in these Mediterranean holm oak forests.

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.