Glutamine synthetase (GS) showed highest expression and activity in bud (youngest topmost leaf) of Camellia sinensis, lower in older leaves, while lowest activity in stem and roots. GS expression and activity was increased by ammonium and nitrate and also by cadmium and salt stress but decreased by copper, aluminum, drought, cold and heat stress.

Wild-abortive (WA), Honglian (HL) and Baro-II (BT) are three important cytoplasmic male sterility (CMS) types in rice. It is essential to investigate genetic mode and allelism of fertility restorer (Rf) genes and the relationship between Rf and CMS. Fertility of the all test-cross F₁ plants shows that the restorer-maintainer relationship is similar for HL-CMS and BT-CMS, while that is variance for WA-CMS and HL-CMS (or BT-CMS), respectively. Genetic analysis of Rf genes indicates that HL-or BT-CMS are controlled by single dominant Rf gene and WA-CMS is controlled by one or two pairs of dominant Rf genes, which reflects the characters of the gametophytic and sporophytic restoration CMS type. It is concluded that there are at least three Rf loci in different accessions with Rf genes for each CMS type.

Cell wall composition in leaves and regenerating leaf-derived protoplasts was studied in Beta vulgaris L. and Nicotiana tabacum L. Several oligosaccharides that characterize arabinogalactan proteins (AGPs) and pectins were visualized in situ by a series of immunocytochemical reactions. The most conspicuous difference between the two species involved the expression of AGP epitopes that bind LM2 and MAC207 in only sugar beet cells; both epitopes being characterized by the presence of glucuronic acid (GlcA). Moreover, B. vulgaris leaves and protoplast-derived cells showed lower content of pectin side-chains bearing (1→4)-β-D-galactose residues as compared to N. tabacum.

Treatment of tomato seedlings (Lycopersicon esculentum Mill. cv. 63/5 F1) with increasing CdCl₂ concentrations in the culture medium resulted in Cd accumulation more important in roots than in leaves. Biomass production was severely inhibited, even at low Cd concentration. Cd reduced chlorophyll content in leaves and enhanced lipid peroxidation. An increase in antioxidative enzyme (superoxide dismutase, ascorbate peroxidase, guaiacol peroxidase, glutathione reductase) activities was more pronounced in leaves than in roots, while catalase activity increased only in roots. In addition, changes in isoenzyme composition were observed using the non-denaturing polyacrylamid gel electrophoresis.

Nicotiana is a small and well characterized genus of Solanaceae and in this study we have used polymorphisms in phytochrome A coding sequence (phyA) and promoter to asses the phylogenetic relationships among species representative of all the sections of the genus. Allopolyploid species kept the two copies of the gene derived from each of the progenitors as resulted from the analyses of the coding region and promoter. Moreover, both copies of phyA present in tetraploids are transcribed, indicating that are properly regulated and do not undergo silencing.

Fourteen efficient inter-simple sequence repeat (ISSR) primers were screened and optimized for detecting the genetic diversity in wild populations of Glycyrrhiza uralensis Fisch. By using these primers, 249 polymorphic bands out of a total of 270 (92.2 %) were generated from 70 individuals of 4 wild G. uralensis populations sampled from Inner Mongolia Province of China. Nei's gene diversity (h) and Shannon index (I) calculated from the data matrix of the ISSR phenotypes revealed a high level of genetic diversity with h = 0.268 and I = 0.415 within this plant. Analysis of molecular variation (AMOVA) showed that most of the genetic variation (81 %) occurred within the populations, whereas the variance among populations was only 19 %. The UPGMA tree based on Nei's unbiased genetic diversity illustrated that populations from Bulage and Bayanwusu were genetically close related, while the population from Shanghaimiao was found to be the most diverse from the other three. The high genetic diversity implies that the wild resources of this species could be restored soon if an appropriate and efficient protection strategy was employed. Our results also provided an optimized method for evaluating genetic diversity of G. uralensis using ISSR markers which was useful for further investigation.

Seed germination and micropropagation protocols of the medicinal species Maytenus canariensis (Loes.) G. Kunkel & Sunding were optimized. In vitro seed germination occurred (86 to 94.7 %) only after treatment of the seeds with H₂SO₄, followed by surface sterilization and culture on solid nutrient medium without any growth regulators. Micropropagation failed when explants were taken from mature trees, and browning of the nutrient medium frequently occurred despite testing many growth media. Nonetheless, adventitious shoot regeneration was achieved employing axillary or apical buds taken from 2-2.5 months old plantlets obtained after in vitro germination of seeds, following culture on nutrient media supplemented with benzylaminopurine, kinetin and naphthalenacetic acid (NAA), attaining up to 3.9 shoots per explant, after 4-6 months. Root induction was best on a medium containing 4.0 mg dm^-3 NAA, achieving a 100 % induction. After hardening of rooted plants, survival after transfer to soil was 71.43 %.

CONSTANS (CO) has a central role in the photoperiodic regulation of flowering in Arabidopsis thaliana. We show here that potato (Solanum tuberosum ssp. andigena) plants constitutively expressing Arabidopsis CO (pACo plants) flower late under all photoperiodic conditions tested. Exogenous application of gibberellic acid to pACo plants corrected their short stem phenotype but not their late flowering. To further understand the effect of CO in potato, we used three photoperiodic conditions: short days (SD), which strongly induce tuberisation of wild type plants, SD supplemented with a night break (SD+NB), which are moderately inductive, and tuberisation-inhibiting long days. Tuberisation of pACo plants was delayed under SD and very strongly delayed or completely inhibited under SD+NB, suggesting that CO affects an autonomous pathway controlling potato tuberisation. In addition, tuber yield, a trait of high agronomic relevance, was significantly increased in pACo plants expressing moderate CO levels. Our results indicate that CO affects flowering and stem elongation through distinct mechanisms and suggest that its effects on flowering and tuberisation in potato are photoperiod-independent.

A 51-kDa soluble protein was over-expressed in wheat (Triticum aestivum) seedlings by the treatment of seeds before germination with 50 µM CdCl₂ for 48 h and subsequently washed off Cd²⁺. This protein designated as Cd stress associated protein (CSAP), was purified. Polyclonal antibody was raised against CSAP for localizing the protein in root tissue of treated and control seedlings. It was observed that CSAP was located below the plasma membrane and outer periphery of the tonoplast. This unique type of organized localization of CSAP is suggestive of defensive role against metal phytotoxicity. N-terminal analysis of CSAP and expressed sequence tags (EST) database search of wheat sequences suggests that this protein has not been reported earlier in higher plants.

Efficient plant regeneration through somatic embryogenesis was established for safflower (Carthamus tinctorius L.) cv. NARI-6. Embryogenic calli were induced from 10 to 17-d-old cotyledon and leaf explants from in vitro seedlings. High frequency (94.3 %) embryogenic callus was obtained from cotyledon explants cultured on Murashige and Skoog's germination (MSG) basal medium supplemented with thidiazuron, 2-isopentenyladenine and indole-3-butyric acid. Primary, secondary and cyclic somatic embryos were formed from embryogenic calli in a different media free of plant growth regulators, however, 100 % cyclic somatic embryogenesis was obtained from cotyledon derived embryogenic calli cultured on MSG. Somatic embryos matured and germinated in quarter-strength MSG medium supplemented with gibberellic acid. Cotyledons with root poles or non root poles were converted to normal plantlets and produced adventitious roots in rooting medium. Rooted plants were acclimatized and successfully transferred to the field.

Effect of plant growth regulators, explant size, season of explant collection, temperature (20, 25 and 30 °C) and photoperiod on in vitro lotus (Nelumbo nucifera Gaertn.) shoot formation and growth were examined. Shoots formation was greatly influenced by growth regulators, explant size and season of explant collection. The maximum number of shoots were induced from bud explants on Murashige and Skoog (MS) medium containing 4.44 µM benzyladenine (BA) + 0.54 µM α-naphthalene acetic acid (NAA). Explants formed by bud of one expanded and one unexpanded leaf, which was collected in spring gave encouraging results of shoot production. Higher temperature favoured shoot induction and subsequent growth was much better at 25 °C compared to that at 20 and 30 °C.

To further optimize a culture medium for induction of direct embryo formation of Oncidium cvs. Gower Ramsey and Sweet Sugar, five kinds of carbon sources, cellibiose, fructose, glucose, maltose and sucrose at 10, 20, 30 and 60 g dm^-3 were tested in this study. Cellibiose supply had an inhibitory effect and resulted in high percentage of explant browning in both cultivars. By contrast, fructose, glucose and sucrose were all effective for direct embryo induction. In cv. Gower Ramsey, the suitable ranges of concentration were found at 30-60 g dm^-3 of sucrose, 10-20 g dm^-3 of glucose and 20-30 g dm^-3 of fructose, respectively. The suitable ranges for cv. Sweet Sugar were at 20-60 g dm^-3 of sucrose, 10-30 g dm^-3 of glucose, 10-20 g dm^-3 of fructose and 30-60 g dm^-3 of maltose, respectively. The highest amount of embryos was obtained at 30 g dm^-3 of sucrose for cv. Gower Ramsey and at 20 g dm^-3 of glucose for cv. Sweet Sugar.

This study aims to understand the changes in the transcriptome of durum wheat (Tricitum durum cv. Balcali-85) upon exposure to varying Cd concentrations using mRNA differential display (mRNA DD) technique. Sequence analyses of the two heavily induced genes upon exposure to Cd showed high homology to NADH dehydrogenase subunit 1 (EC907725) and PsaC gene encoding a photosystem 1 (PS 1) 9 kDa subunit protein (EC907731). Additionally, three differentially expressed genes (EC907726, EC907729 and EC907730) were identified. Their sequence analyses revealed no significant homologies to known genes. The expressions of NADH dehydrogenase subunit 1 and PsaC genes were confirmed by Northern blot analysis and quantified by real time PCR. This is the first report for the induction of NADH dehydrogenase subunit 1 gene during Cd stress in wheat.

This study was conducted to determine the reciprocal effects for anther culture response in wheat (Triticum aestivum L.) using a set of 4 × 4 full diallel crosses. Both reciprocal and nuclear genetic effects were highly significant for anther culture response and useful for selection and breeding purposes. General combining ability (GCA) effects were predominant for all investigated anther culture traits. Also, significant differences for specific combining ability (SCA) effects were detected between reciprocal crosses. Although significant reciprocal differences for responding anther, callus number and green plant regeneration were recorded in some reciprocal crosses, there were no significant reciprocal differences for albino plant regeneration. The use of one parent as male or female could lead to change at the production of green plants from the F₁ hybrids and screening of inbred lines for response to anther culture, without reciprocal effects, could decrease the utilization of breeding material.

We report here the successful micropropagation of adult Juniperus phoenicea L. with respective ploidy stability studies. Microcuttings with axillary buds were grown on five media supplemented with different growth regulator combinations. Best elongation rates were achieved on Driver and Kuniyuki (DKW) medium supplemented with kinetin alone or with naphthaleneacetic acid (NAA), while Rugini olive (OM) medium stimulated the development of new branches. Shoots growing on Murashige and Skoog (MS) medium browned and showed necrotic zones. Shoots of second to fourth subcultures usually had higher elongation rates than those of the first culture. For rooting assays, half strength DKW and OM media, different concentrations of growth regulators, auxin continuous exposure vs. dipping and the type of solid matrix were assessed. During rooting assays, two morphotypes were observed with one type having well developed internodes and the other showing hyperhydratation and no internode development. High rooting rates (40 %) were only obtained in the first morphotype shoots exposed for 5 min to 2.4 µM IBA and then transferred to OM medium without growth regulators. Plants were acclimatized in pots containing a mixture of peat and Perlite (3:2) in greenhouse with progressive reduction of relative humidity. A flow cytometric screening for major ploidy changes revealed no differences among the morphotypes and between them and the mother plant. Also the nuclear DNA content of this species was estimated for the first time using flow cytometry (2C = 24.71 pg).

Photosystem 1 and 2 and antioxidant enzyme activities were determined in wheat (Triticum aestivum L. cv. Sonalika) leaves. Seedlings from both control seeds and seeds soaked in solutions like dithiothreitol, thioglycollic acid and thiourea were subjected to water stress induced by polyethylene glycol. Photosystem 1 and 2 activities were less inhibited by water stress due to seed soaking with sulphydryl compounds. The changes in activities of antioxidant enzymes induced by water stress were higher in seedlings from thiol-pretreated seeds than from water-soaked seeds.

The apple (Malus domestica Borkh) rootstock M 4 shoots were grown in vitro for 4 weeks on Murashige and Skoog (MS) medium containing three NaCl concentrations (35, 100 and 200 mM) in combination with two CaCl₂ concentrations (5 and 10 mM). Inclusion of 10 mM CaCl₂ in the medium, in the presence of 35 mM NaCl, significantly increased the number of shoots and the fresh mass compared to 5 mM CaCl₂. The number of shoots, length of shoots, and the fresh mass of cultures were very low in the presence of 100 and 200 mM NaCl, independently of CaCl₂ concentration of the medium. By increasing NaCl and CaCl₂ concentrations in the culture medium, contents of N, Na, Cl, proline and soluble sugars in plantlets increased, whereas K, Mg, B, Zn and chlorophyll content decreased in comparison to the control.

In this study, seven cDNA fragments of genes, differentially expressed in ovaries after pollination in Cymbidium hybridium, were identified and characterized by mRNA differential display reverse transcription polymerase chain reaction (DDRT-PCR). Four (CDD-313, CDD-272, CDD-265, CDD-243) among these seven cDNA fragments showed no significant homology with ESTs or genes in the databases of NCBI; another three (CDD-193, CDD-218, CDD-470) showed significant homologies with sequences encoding components of an ABC-type transporter, a GTPase and 40S ribosomal S3 proteins (RPS3), respectively. The differential expression patterns of them were confirmed by reverse Northern dot blot analysis. More interestingly, CDD-470 appeared to be present and highly expressed in the pollinated ovaries and encoded a new factor of RPS3 participating in cell growth and proliferation. We deduced that this 40s ribosomal S3 like protein was involved in ovary development of orchids.

Effect of osmotic stress and sodium nitroprusside (SNP, NO donor) pretreatment on growth and proline metabolism of wheat seedlings was investigated. Polyethylene glycol 6000 treatment for 2, 4 and 6 d could be termed as mild, moderate and severe stress, respectively, according to decrease in the relative water content. Severe osmotic stress significantly decreased the growth and photochemical efficiency, and increased proline content due to activation of its synthesis. 0.2 mM SNP pretreatment enhanced growth of wheat seedlings, increased variable to maximum fluorescence ratio (F_v/F_m) and fluorescence yield, while decreased proline content. However, 2 mM SNP retarded the seedlings growth and chlorophyll a fluorescence, and increased proline accumulation. Our results showed that NO might be involved in the regulation of osmotic stress in a concentration-dependent manner.

The interplay between nitric oxide (NO) and reactive oxygen species can lead to an induction of cell death in plants. The aim of our work was to find out if cyanide released from sodium nitroprusside (SNP; a donor of NO) could be involved in the cell death induction, which is triggered by SNP and H₂O₂. Cell suspension of Nicotiana tabacum L. (line BY-2) was treated with 0.5 mM SNP, 0.5 mM potassium ferricyanide (PFC; analogue of sodium nitroprusside which can not release NO) and/or by 0.5 mM glucose with 0.5 U cm^-3 glucose oxidase (GGO; a donor system of H₂O₂). The cell death was induced only by combination of SNP and GGO. Thus cyanide released was not involved in the induction of cell death. However, SNP showed toxic effect because of decrease in activities of intracellular oxidoreductases and esterases. The cell death caused by SNP and GGO occurred within 12 h. During cell death either length or width of the cell increased. Central vacuole was formed in 20 to 40 % of cells. Most of the dead cells showed a condensed cytoplasm. Two hallmarks of programmed cell death (PCD), chromatin condensation and blebbing of nuclear periphery, were observed. However, oligonucleosomal fragmentation of DNA, another hallmark of PCD, was not detected.

Protoplasts isolated from wild cotton Gossypium davidsonii were cultured in KM₈P medium supplemented with different phytohormones. The most effective combination was 0.45 µM 2,4-dichlorophenoxyacetic acid, 2.68 µM α-naphthaleneacetic acid and 0.93 µM kinetin and the division percentage at the 8^th day was 30.78 ± 3.04 %. The density of protoplasts at 2-10 × 10⁵ cm^-3 was suitable for protoplast division and calli formation, with a division percentage of 32.21 ± 3.64 % and a plating efficiency of 9.12 ± 2.61 % at the 40^th day. The optimal osmotic potential was achieved using 0.5 M glucose or 0.1 M glucose plus 0.5 M mannitol. Protoplasts were cultured in three ways, a double-layer culture system, with liquid over solid medium was proved to be the best way. Embryo induction was further increased by addition of 0.14 µM gibberellic acid.

Cd accumulation, its effects on elongation growth of maize coleoptile segments, pH changes of their incubation medium and the membrane potential of parenchymal cells were studied. The Cd content increased significantly with exposure to increasing cadmium concentrations. Coleoptile segments accumulated the metal more efficiently in the range 10-100 µM Cd, than in the range 100-1000 µM Cd. Cd at concentrations higher than 1.0 µM produced a significant inhibition of both growth and proton extrusion. 100 µM Cd caused depolarization of the plasma membrane (PM) potential in parenchymal cells. The simultaneous treatment of maize coleoptile segments by indole-3-acetic acid (IAA) and Cd, counteracted the toxic effect of Cd on growth. Moreover, our data also showed that 100 µM Cd suppressed the characteristic IAA-induced hyperpolarization of the membrane potential, causing membrane depolarization. These results indicate that the toxic effect of Cd on growth of maize coleoptile segments might be, at least in part, caused via reduced PM H⁺-ATPase activity.

The present paper reports a protocol for minimum growth conservation of Drosophyllum lusitanicum (L.) Link. in vitro. Double-node cuttings were maintained for 4, 8 and 12 months at 5 or 25 °C in the dark. The effects of sucrose either alone at 5, 20, 30, 40 and 60 g dm^-3 or at 20, 40 and 60 g dm^-3 in combination with 20 g dm^-3 mannitol, on survival and post-storage shoot multiplication efficiency were investigated. The cultures could effectively be conserved under minimum growth at 5 °C for 8 months on Murashige and Skoog's medium supplemented with 60 g dm^-3 sucrose, 20 g dm^-3 mannitol and 0.91 µM zeatin. Following extended conservation, the cultures could be successfully regenerated into new shoots, and they were morphologically similar to those of non-stored controls.

Cassia auriculata L. seedlings were irradiated with ultraviolet B (UV-B) in an environment-control chamber. The two doses assayed (7.5 and 15.0 kJ m^-2) induced oxidative damage with an increase in lipid peroxidation and hydrogen peroxide and a decrease in chlorophyll and total phenol contents. The ascorbate and dehydroascorbate content as well as the reduced glutathione/oxidized glutathione content and ratio were significantly increased. The UV-B stress led to significant increases of the activity of superoxide dismutase, catalase, peroxidase and polyphenol oxidase. It is suggested that Cassia seedlings try to counteract high concentrations of oxygen species produced under UV-B stress through a co-ordinated increase in the contents and activities of antioxidants involved in their detoxification.

Embryogenesis and plant regeneration was achieved from callus cultures derived from unpollinated ovaries of Psoralea corylifolia L. Callus was initiated from unpollinated ovaries on Murashige and Skoog (MS) medium supplemented with 2.2 µM N ⁶-benzyladenine (BA) and various concentrations of α-naphthaleneacetic acid (NAA (2.7 to 10.7 µM) or 2,4-dichlorophenoxyacetic acid (2,4-D (2.3 to 9 µM) alone or in combination. Highly organized embryogenic callus induction, embryo development, proliferation and maturation were achieved on transfer of callus clumps to MS medium supplemented with NAA (0.27 µM) or 2,4-D (0.23 µM) alone or in combination with BA (2.2 to 8.8 µM). Addition of abscisic acid (ABA) (0.95 to 5.8 µM) to the medium enhanced average numbers of cotyledonary stage embryos, the maximum number (34.6 ± 0.7) being obtained on MS medium containing 0.27 µM NAA, 2.2 µM BA and 3.8 µM ABA. Embryos germinated on MS medium supplemented with BA (0 to 8.8 µM). MS medium containing gibberellic acid (GA₃ (0.29 to 5.8 µM) enhanced embryo germination frequency, the highest frequency (66.7 %) occurring on MS medium containing 2.2 µM BA and 4.3 µM GA₃. Effect of several concentrations (3.0 to 6.0 %) of sucrose or maltose was also observed on germination of embryos. MS medium enriched with maltose supported high frequency of embryo germination.