In the reproductive organs of maize (Zea mays L.), the changes in transcription that occur during meiosis at early stage of water deficit were characterized. We used oligo microarray analysis, which included 57452 transcripts representing more than 30 000 genes, and combined this with reverse Northern blot analysis. After 1 d stress, 1 809 transcripts were differentially expressed (by 2-fold or greater) with 34 % of them being upregulated in the tassels, while in the ears 861 transcripts were differentially expressed with 41 % being upregulated. Of these, 33 transcripts were upregulated in both organs, including those involved in protective functions, reactive oxygen species detoxification, nitrogen metabolism and gibberellin metabolism. In contrast, the transcripts involved in polyamine and sugar metabolism were downregulated.

In this work the volatiles emitted from in vitro shoot-cultures and micropropagated plants of Lavandula viridis L'Hér. were characterized and compared with those obtained from the field-grown mother-plant, using headspace solid phase micro-extraction following by capillary gas chromatography coupled to mass spectrometry (HS-SPME-GC/MS). The headspace composition consisted mainly in oxygenated monoterpenes (66.7-79.2 %), where the major constituents emitted by the mature field-grown mother-plant, in vitro shoot-cultures and micropropagated plants were 1,8-cineole (74.0, 51.9 and 57.8 %) and camphor (2.9, 15.3 and 8.7 %), respectively. The headspace of in vitro shoot-cultures and micropropagated plants showed greater amount of α-pinene, camphene, β-pinene, β-selinene and selina-3,7(11)-diene, when compared with the field-grown mother-plant.

An efficient protocol for micropropagation of Harpagophytum procumbens DC., an endangered African medicinal plant, was developed. Maximum shoot multiplication without callus was obtained from nodal explants cultured on Murashige and Skoog (MS) basal salts plus Gamborg's (B₅) vitamins supplemented with 0.1 mg dm^-3 indole-3-acetic acid and 5.0 mg dm^-3 kinetin. The shoots were subsequently subcultured every 3 weeks on the same medium. Detached axillary shoots were transferred to MS basal salts plus B₅ vitamins supplemented with various concentrations of α-naphthalene-acetic acid or indole-3-butyric acid (IBA), ranging from 0.5 to 2.5 mg dm^-3 and 100 % rooting and optimal subsequent acclimatization was achieved on 1.0 mg dm^-3 IBA. After 4 weeks of culture, the rooted shoots (>5 cm) were planted in pots containing peat, vermiculite and bark (2:1:1), covered with plastic domes and maintained at 25 °C for 2 weeks before being transferred to a glasshouse. Plant survival was about 40 %.

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.

Calcium chloride (0.3 or 10 mM) was applied to the growth medium before, together with, or after sodium chloride application, and the effect of the timing of Ca application on the alleviation of salt stress was investigated. Seedlings of maize, tall fescue, and reed canarygrass were grown in medium with 0 and 200 mM NaCl for 5 d. Regardless of the plant species the maximum alleviation of NaCl stress was achieved when CaCl₂ and NaCl coexisted in the growth medium. The effects of Ca application were connected with the decrease in the Na content in the plant roots and shoots and increased ATPase activity in the roots.

MADS-box genes are known to be important for the development of flowers. Two MADS-box genes (MCAG2 and MCAG6) were isolated from the bitter gourd (Momordica charantia) female bud based on the MADS-box conserved sequences. The complete cDNA sequences of MCAG2 and MCAG6 encode a 231 and a 247 amino acid protein, respectively. Sequence comparison and phylogenetic analysis showed that MCAG2 and MCAG6 had high identities of amino acid with AG-like and AGL6-like genes, respectively. The alignment of the deduced amino acid sequence of AGL6-like genes revealed that there were two highly conserved regions in the C-terminus, which were designated AGL6 motif I and AGL6 motif II. Phylogeny reconstructions suggested that AGL6-like genes were divided into three major clades. RT-PCR analysis of the MCAG2 and MCAG6 genes showed that they were both expressed in floral organs at different levels. However, MCAG6 was also expressed highly in shoot apex. Quantitative real-time reverse transcriptase-polymerase chain reaction analysis indicated that the expression of MCAG2 was detected at high levels in carpel, whereas MCAG6 was detected at high levels in shoot apex. The gene expression patterns suggest that MCAG2 and MCAG6 have a role in regulating bitter gourd floral development.

The effect of cadmium on growth and contents of glutathione (GSH) and phytochelatins (PCs) were investigated in roots and leaves of tomato plants (Lycopersicon esculentum Mill. cv. 63/5 F1). The accumulation of Cd increased with external Cd concentrations and was considerably higher in roots than in leaves. Dry mass production decreased under Cd treatment especially in leaves. In both roots and leaves, exposure to Cd caused an appreciable decline in GSH contents and increase in PCs synthesis proportional to Cd concentrations in the growth medium. At the same Cd concentration, PCs production was higher in roots than in leaves. The implication of glutathione in PC synthesis was strongly suggested by the use of buthionine sulfoximine (BSO). The major fraction of Cd accumulated by tomato roots was in the form of a Cd-PCs complex.

The influence of artificial wounding on biosynthesis of flavonoids and hydroxycinnamic acids was studied in bilberry leaves using two separate wounding experiments. In the first experiment bilberry leaves were wounded by cutting. The expression of the first gene from flavonoid pathway, chalcone synthase (CHS) and a wound induced pathogenesis related PR-10 gene was analysed from samples collected immediately and after 3, 6, 24 h and 4 d from the wounding treatment. In the second experiment annual shoots were removed. Proanthocyanidins, flavonol glycosides and hydroxycinnamic acids were quantified in leaf samples after 0-5 d (experiment 1) and 5 weeks (experiment 2) from the treatment. In the first experiment, no change was observed in the expression of CHS whereas increase in expression of PR-10 gene was detected after 6 h of wounding treatment. In both experiments, the contents of flavonol glycosides and hydroxycinnamic acids were not influenced by the wounding treatment and the contents of proanthocyanidins were decreased.

The nucleolar vacuole formation in soybean root meristematic cells from seedlings grown 3 d at temperature 25 °C (control), 3 d at temperature 25 °C and then transferred to 10 °C (chilling) for 4 d, and after recovery for 1.5, 3, 6, 12 and 24 h at 25 °C were observed on semi-thin sections. Simultaneously, autoradiographic studies with ³H-uridine on squashed preparations were carried out. During recovery of plants, the number of vacuolated nucleoli increased gradually from 24 % after 1.5 h up to 40 % after 24 h, while in the control there were 18 % of nucleoli with vacuoles and after 4-d chilling only 5 %. Labelling of cells during 20-min incubation in ³H-uridine and during 80-min post-incubation in non-radioactive medium was increased in recovered plants in comparison with the control and chilled plants. The conclusion has been drawn that nucleolar vacuoles in soybean plants are formed as a result of migration of granular component accumulated in nucleolus during 4-d chilling.

The in vitro response of sweet cherry (Prunus cerasus × P. canescens) rootstock Gisela 5 to increasing water deficit in the culture medium was studied. Water stress induced by the incorporation of 1, 2 and 4 % polyethylene glycol (PEG-8000) into the Murashige and Skoog medium was applied for 6 weeks. PEG-induced water stress reduced shoot dry mass, length, water content and relative chlorophyll content. Water stress also induced leaf necrosis without causing loss of viability in the explants. The increase in malondialdehyde content indicated oxidative stress. The activities of antioxidant enzymes, such as superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX), peroxidase (POX) and glutathione reductase (GR) were also significantly elevated. The concentrations of K, Ca, Fe and Mn of shoots were decreased.

The effect of different oxygen availability on the nitrate reductase (NR, EC 1.6.6.1) activity in cucumber roots was studied. NR activity measured in the presence of Mg²⁺ (actual NR activity) as well as activity measured with EDTA (maximum NR activity) increased distinctly after 30 min of root incubation in a medium flushed with N₂ (anaerobic conditions). In contrast, aeration of roots (aerobic conditions) decreased both enzyme activities. Such inactivation of NR was rapidly reversed after transferring the roots to anaerobic conditions. An air-induced decrease of the actual enzyme activity was prevented by staurosporin, a protein kinase inhibitor; whereas microcistin LR, an inhibitor of protein phosphatases, completely eliminated the reactivation of NR actual activity under limited oxygen availability. An increase of the NR actual activity in roots incubated in a nitrogen-flushed buffer was correlated with a lower content of ATP in root tissues. These data suggest that reversible protein phosphorylation is involved in the regulation of NR activity under limited oxygen. On the other hand, feeding roots with inhibitors of protein kinases as well as phosphatases did not affect the maximal activity of NR indicating that other modification(s) of enzyme activity could also function in cucumber roots. Since the changes in the expression level of gene encoding nitrate reductase (CsNR) under different oxygen availability were not correlated with the enzyme activity, the transcription level of oxygen action was excluded. On the other hand, it was demonstrated that oxygen-induced alteration of NR was dependent on the ratio of oxidized/reduced pyridine nucleotides in tissues. In aerobic conditions, when maximal NR activity was inhibited, a drop of the NAD(P)H level was also observed. These data point to hysteretic modifications of NR protein induced by NAD(P)H as the target of reversible and rapid changes in maximal enzyme activity under different oxygen availability.