The production of reactive oxygen species (ROS) and the ways by which ROS are generated are very important facts related to heavy metal toxicity in plants. In this work, superoxide anion (O₂ ^.-) generation diminished in cadmium treated sunflower (Helianthus annuus L.) leaf discs, and this reduction was time and Cd-concentration dependent. In line with these findings, we observed that NADPH-dependent oxidase activity was significantly inhibited by 0.1 and 0.5 mM Cd²⁺ treatments and the expression of the NADPH oxidase putative gene related to O₂ ^.- synthesis in sunflower leaves was 83 % inhibited by 0.1 mM CdCl₂ and almost completely depleted by 0.5 mM CdCl₂.

In Pinus peuce zygotic embryo culture grown on Gresshoff and Doy (1972; GD) basal medium, 2.22 μM benzyladenine (BA) was superior in promoting adventitious bud induction during 4 weeks comparing to kinetin or BA + kinetin. Shoot elongation was achieved on half-strength GD medium devoid of plant growth regulators and containing activated charcoal. Pulse treatment with 1 mM indole-3-butyric acid (IBA) for 2 h, followed by transfer to half-strength GD medium, produced the most efficient rooting. Rooted shoots were transplanted to the greenhouse and plantlets continued to grow and developed into phenotypically normal plants. Up to 10 plants per explant can be obtained within 36 weeks from culture initiation.

Choline monooxygenase (CMO) is the first regulatory enzyme in the biosynthetic pathway for glycine betaine, an effective osmoprotectant in Kochia scoparia, a highly drought- and salt-tolerant species. In seedlings, CMO transcript levels are rapidly increased in response to both NaCl and osmotic stress treatments. The mRNA level in shoots was substantially higher than in roots. The rapid induction seen in whole plants was in contrast to the apparent down-regulation observed in suspension-cultured K. scoparia cells in response to the same salt stress. Treatment with exogenous abscisic acid (ABA) or fluridone shows that CMO induction proceeds via an ABA-independent signal transduction pathway. Examination of the CMO upstream regulatory region reveals a number of stress response-related elements, some of which may be involved in the stress tolerance shown by this species.

In this study, we report a function of myo-inositol-O-methyltransferase (Imt1) in response to low temperature stress using transgenic Arabidopsis thaliana. Imt1 gene was constructed identical to the Imt1 gene from a halophyte Mesembryanthemum crystallinum. After cold stress, the Imt1 transgenic plants exhibited stronger growth than the wild type plants. The elevated cold tolerance of the Imt1 over-expressing plants was confirmed by the lower electrolyte leakage and accumulation of malondialdehyde, but higher proline and soluble sugar contents in transgenic than wild type plants.

An ascorbate-deficient semi-dwarf mutant asfL-1 was detected in 250 Gy γ-ray treated grass pea (Lathyrus sativus L.) cv. BioR-231. The mutant contained only 42 % of leaf and 20 % of root ascorbate content of mother control (MC). I investigated the possible causes of ascorbate deficiency and its effect on growth and antioxidant defense in control and 150 mM NaCl-treated seedling after 60 d growth period. Ascorbate deficiency was due to significant reduction in activities of monodehydroascorbate reductase and dehydroascorbate reductase as well as increase in ascorbate oxidase, leading to considerable decrease in redox state. Despite low ascorbate pool and decrease in ascorbate peroxidase activity, shoot and root biomass production in asfL-1 mutant were similar to MC plants, even at NaCl treatment. High accumulation of glutathione (GSH) coupled with high activities of GSH reductase, catalase, GSH peroxidase and peroxidase in both tissues of the mutant permitted efficient recycling of GSH and scavenging of H₂O₂ through well integrated catalase/peroxidase system, despite high superoxide dismutase activity under NaCl treatment. The collapse of this system led to inhibition of growth in NaCl-treated mother plants. Together, the results suggested that asfL-1 plants undertook a major reshuffle in its antioxidant defense machinery, which effectively counterbalanced the negative impact of ascorbate deficiency and remained unperturbed by NaCl treatment to maintain normal growth and biomass production.

Desiccation of Xerophyta scabrida caused considerable damage of chloroplast ultrastructure together with a complete loss of chlorophyll. Upon rehydration, the relative water content of the pale-green leaves almost reached that of the dark-green ones, however, the Chl content and photosynthetic activity remained lower. The process of reconstitution of the photosynthetic apparatus in the re-greening leaves was accompanied by changes in fatty acid (FA) content. The amount of the FA methyl esters was more than 2-fold higher in the green leaves as compared to the dry ones and slightly increased after rehydration in the pale-green leaves. Among the three main fatty acids in the leaves, oleic, palmitic and linoleic acid, the latter increased more than 3-fold during rehydration. This acid is concentrated mainly in the glycolipids and this was an indirect indication for the restoration of the photosynthetic apparatus. Our results showed that rehydration of X. scabrida led to a decrease of the saturated FA in parallel with an increase of the unsaturated FA, thus indicating increased membrane permeability. The observed changes in the lipid content can be considered as a characteristic feature of X. scabrida and most probably of other poikilochlorophyllous species.

This study investigated the regulation of ascorbate and glutathione metabolism by nitric oxide in Agropyron cristatum leaves under water stress. The activities of ascorbate peroxidase (APX), glutathione reductase (GR), monodehydroascorbate reductase (MDHAR), dehydroascorbate reductase (DHAR), L-galactono-1,4-lactone dehydrogenase (GalLDH) and γ-glutamylcysteine synthetase (γ-ECS), and the contents of NO, reduced ascorbic acid (AsA), reduced glutathione (GSH), total ascorbate and total glutathione increased under water stress. These increases were suppressed by pretreatments with NO synthesis inhibitors N ^G-nitro-L-arginine methyl ester (L-NAME) and 4-carboxyphenyl-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (cPTIO). However, application of L-NAME and cPTIO to plants sufficiently supplied with water did not affect the activities of above mentioned enzymes and the contents of NO and above mentioned antioxidants. Pretreatments with L-NAME and cPTIO increased the malondialdehyde (MDA) content and electrolyte leakage of plants under water stress. Our results suggested that water stress-induced NO is a signal that leads to the upregulation of ascorbate and glutathione metabolism and has important role for acquisition of water stress tolerance.

Historically, sugar beets were selected from fodder beets. We used mitochondrial minisatellite loci to analyze cytoplasmic genetic diversity in fodder beet and sugar beet. Among the 8 sugar beet accessions examined we identified 3 multi-locus haplotypes. These 3 haplotypes were a subset of 5 haplotypes identified among the 29 fodder beet accessions examined. All but one haplotype in fodder beet comprised, in turn, a subset of 12 haplotypes identified previously in leaf beets. Such apparent decreases in cytoplasmic genetic diversity must result from genetic bottlenecks associated with domestication and the ensuing breeding processes. We also detected the haplotype associated with the male-sterile Owen cytoplasm of sugar beet in the fodder beet gene pool. Furthermore, the presence of a 39 kDa protein associated with the Owen cytoplasm was confirmed in two fodder beet plants by Western blot analysis. These results lead us to speculate that the Owen cytoplasm may have originated in fodder beet, from which sugar beet was derived.

Nucleoside diphosphate kinase (NDPK) operates in the homeostasis of cellular nucleoside triphosphate (NTP) pools and the cytosolic NDPK1 is the main NDPK isoform in plants, accounting for more than 70 % of total NDPK activity in plant. A full length cDNA (697 bp), designated as CsNDPK1 was cloned from Camellia sinensis (L.) O. Kuntze leaves. Sequence analysis of CsNDPK1 shows several motifs, binding and catalytic sites which are highly conserved among other NDPKs. Southern blot analysis revealed that tea genome has two copies of CsNDPK1. Transcription pattern analysis indicated that CsNDPK1 is expressed in all tissues examined, but expressed more in buds than in other organs.

Paspalum notatum Flügge is a grass species organized as an agamic complex. The objective of the current research was to survey the frequencies and variation of cytosine methylation at CCGG sequences in diploid and tetraploid genotypes, and to determine the occurrence of methylation changes associated with tetraploidization by using methylation-sensitive amplification polymorphism (MSAP) markers. No differences were found in the average proportions of methylated CCGG sites between cytotypes, but methylation patterns were significantly more variable in tetraploids. In both groups of plants, epigenetic and non-epigenetic variation correlated significantly when compared by Mantel tests. The evaluation of 159 common MSAP markers showed that 18.86 % of them differed in their methylation status in the different ploidies. Dendrogram analysis, reflecting epigenetic distances, showed that the four diploids and one experimentally-obtained sexually-reproducing tetraploid, grouped together. MSAP analysis performed on a diploid plant and its autotetraploid derivative showed that new epialleles emerged after tetraploidization. Sequencing of several MASP markers showed homologies with low copy genes, non-coding sequences and transposon/retrotransposon elements.

Histone H3 lysine 4 methylations catalyzed by histone lysine methyltransferases (HKMTs), like the Arabidopsis thaliana ATX1 and ATX2, are important epigenetic modifications related to chromatin decondensation and gene activation. In order to study this epigenetic mechanism in monocot cereal plants, we performed homology searches of ATX1 and ATX2 against the Brachypodium distachyon L. Beauv and rice (Oryza sativa L. spp. japonica) genomes, discovering single homologues for each cereal crop representing both Arabidopsis sequences. Using this information, we employed the rolling circle amplification - rapid amplification of cDNA ends (RCA-RACE) method to isolate, clone and characterize HvTX1 from RNA extracted from barley (Hordeum vulgare L.) tissues and studied its expression during seed development and under drought stress. The cloned cDNA sequence contained a 3 093 bp ORF homologous to ATX1 and ATX2. Characterization of the translated HvTX1 transcript sequence revealed the multi-domain nature of the putative protein, including all conserved regions characteristic for ATX1 and ATX2. By comparative genomic analysis and homology searches in EST databases we located, with high probability, the gene coding for HvTX1 on the barley chromosome 5H. Constant elevation of HvTX1 expression was observed during seed development. Expression of HvTX1 after drought stress was analyzed by quantitative real-time polymerase chain reaction (qPCR) in two different barley cultivars with varying drought stress tolerance, revealing HvTX1 drought-induction in a tolerance-specific manner.

The ABC1 protein family (ABC1P), a new family of putative kinases, widely existed in procaryote and eucaryote. A comprehensive genome-wide analysis was carried out in this study to find all ABC1Ps in rice (Oryza sativa subsp. japonica). We identified 15 ABC1P genes in rice. All the ABC1Ps contained an ABC1 domain of about 120 conserved amino acid residues and conserved kinase motifs-VAIK (VAVK, VAMK) and DFG (DEG). The phylogenetic analysis showed that all the ABC1Ps were grouped into three subgroups, and formed a total of 12 sister pairs. Conserved motifs analysed by MEME program indicated that almost all ABC1Ps contains motifs 1, 3, 7, 8 and 9. Predictably, the ABC1Ps were localized in mitochondria or chloroplasts, which implied that the ABC1Ps might be involved in energy metabolism in plants. RT-PCR assays demonstrated that all 15 ABC1P genes were active, and some of them were affected by abiotic stresses (NaCl, high temperature, methyl viologen, abscisic acid and cadmium).

This work focuses on the comparison of field characteristics and amounts of reducing sugars in cold-stored tubers of transgenic plants derived from two potato cultivars. The bacterial gene coding for phosphofructokinase under the tuber-specific promoter was used to support the glycolysis in stored tubers. While the tubers from untransformed control plants steadily accumulated reducing sugars during cold storage, the tubers from transformed plants regardless the genotype were characterized by subsequent decrease in the sugar content. After long period of cold storage the greatest reduction in the reducing sugar content was by more than 60 % compared to control. Before the storage, however, the content of reducing sugars was in 80 % of transgenic lines higher than in control ones. The plants evaluated in field trials for their appearance showed any changes in growth characteristics in about 25 % of the transgenic lines. Despite the introduced modification of sugar metabolism the yield of transgenic plants with normal appearance did not differ significantly from the yield of control plants.

Three constructs harbouring novel Bacillus thuringiensis genes (Cry1C, Cry2A, Cry9C) and bar gene were transformed into four upland cotton cultivars, Ekangmian10, Emian22, Coker201 and YZ1 via Agrobacterium-mediated transformation. With the bar gene as a selectable marker, about 84.8 % of resistant calli have been confirmed positive by polymerase chain reaction (PCR) tests, and totally 50 transgenic plants were regenerated. The insertions were verified by means of Southern blotting. Bioassay showed 80 % of the transgenic plantlets generated resistance to both herbicide and insect. We optimized conditions for improving the transformation efficiency. A modified in vitro shoot-tip grafting technique was introduced to help entire transplantation. This result showed that bar gene can replace antibiotic marker genes (ex. npt II gene) used in cotton transformation.

The Agrobacterium-mediated transformation was done in rice (Oryza sativa L. var. indica) cv. HKR126 and elite cross-bred cv. Pusa Basmati1 (PB1), using strain LBA4404 containing pCAMBIA1300 cloned with gene cassettes; potato proteinase inhibitor and Bacillus thuringiensis endotoxin (plasmid JDW53) or mannitol-1-phosphate dehydrogenase (plasmid RKJ108). Co-cultivation with scutellar-calli derived from mature seeds showed stable and highly efficient transformation. In cvs. HKR126 and PB1, 35 % and 41 % of hygromycin resistant calli were obtained. The transformation efficiency in PB1 (22.0 %) was much higher than in HKR126 (12.5 %). Similarly, PB1 had higher plant regeneration efficiency than HKR126. The shoots regenerated per callus were, 3-4 in HKR126 and 5-6 in PB1. The transformation efficiency with pRKJ108 (18.6 %) was higher than pJDW53 (15.9 %). Polymerase chain reaction (PCR) analysis showed the presence of transgenes in regenerated transgenic plants of both cultivars.

Inter simple sequence repeat (ISSR) marker assay was employed to validate the genetic fidelity of Swertia chirayita plantlets multiplied in vitro by axillary multiplication upto forty-two passages. Sixteen ISSR primers generated a total of 102 amplicons among the tissue-cultured plants. Forty-eight amplicons were amplified in the outlier (a Swertia species). The outlier (negative control) was employed to rule out the possibility that the invariant fingerprint was due to chance alone and that the ISSR technique employed was not discriminatory enough to detect the off-types. A homogenous amplification profile was observed for all the micropropagated plants. The results confirmed the clonal fidelity of the tissue culture-raised S. chirayita plantlets and corroborated the fact that axillary multiplication is the safest mode for multiplication of true to type plants.

DNA content was estimated by flow cytometry in seedlings and in vitro clones of six species: Oenothera paradoxa, Inula verbascifolia ssp. aschersoniana, Rubus chamaemorus, Solidago virgaurea, S. graminifolia and Pueraria lobata. With the exception of P. lobata, there was no difference in genome sizes between seedlings and in vitro cultured plants from any species, indicative that they maintain their genetic stability during in vitro culture. This confirms the usefulness of tissue culture for production of certified plant material to obtain herbal medicines.

The localization was determined of the triterpenoids, asiaticoside and madecassoside, in different organs of glasshouse-grown plants and cultured material, including transformed roots, of two phenotypes of Centella asiatica (L.) Urban of Malaysian origin. Methanolic extracts of asiaticoside and madecassoside were prepared for gradient HPLC analysis. The two phenotypes of C. asiatica exhibited differences in terpenoid content that were tissue specific and varied between glasshouse-grown plants and tissue culture-derived material. Terpenoid content was highest in leaves, with asiaticoside (0.79 ± 0.03 and 1.15 ± 0.10 % of dry mass) and madecassoside [0.97 ± 0.06 and 1.65 ± 0.01 %(d.m.)] in the fringed (F) and smooth leaf (S) phenotypes, respectively. Roots of the F-phenotype contained the lowest content of asiaticoside [0.12 ± 0.01 %(d.m.)], whereas petioles of S-phenotype plants contained the lowest content of asiaticoside [0.16 ± 0.01 %(d.m.)] and madecassoside [0.18 ± 0.14 %(d.m.)]. Transformed roots were induced using Agrobacterium rhizogens and their growth was maximal on Murashige and Skoog basal medium supplemented with 60 g dm^-3 sucrose. However, asiaticoside and madecassoside were undetectable in transformed roots and undifferentiated callus.

Forty-five-days old plants of Indian senna (Cassia angustifolia Vahl.) were subjected to 0-500 µM lead acetate (Pb-Ac) in pot culture. Changes in contents of thiobarbituric acid reactive substances (TBARS), ascorbate, glutathione, proline, sennosides (a+b), and activities of superoxide dismutase (SOD), ascorbate peroxidase (APX), glutathione reductase (GR), and catalase (CAT) were studied at pre-flowering (60 d after sawing, DAS), flowering (90 DAS) and post-flowering (120 DAS) stages of plant development. Compared with the controls, the Pb-Ac treated plants showed an increase in contents of TBARS, dehydroascorbate, oxidized and total glutathione at all stages of growth. However, sennoside yield and contents of ascorbate and reduced form of glutathione declined. Proline content increased at 60 DAS but declined thereafter. Activities of SOD, APX, GR and CAT were markedly increased. Sennoside content was higher at 60 and 90 DAS but lower at 120 DAS, compared to the control.

Two vacuolar green fluorescent proteins (GFP) were stably inserted in Nicotiana tabacum and Nicotiana benthamiana genome, with unexpected difficulties, and compared with A. thaliana cv. Wassilewskaja transgenic plants expressing the same constructs. GFP fluorescence was strong in all tissues of A. thaliana but it was barely visible in Nicotiana. Confocal microscopy analysis revealed a variable distribution of the marker in those cells where GFP fluorescence was visible. The role of light dependent proteases was the variable pointing out more inter-species diversity. GFPs degradation was much higher in Nicotiana spp. than in A. thaliana. The version of GFP used appeared not to be a good vacuolar marker for Nicotiana differentiated tissues, although it can efficiently label vacuoles in protoplasts or calli. Nevertheless the sensitivity of the reporter protein can be used as an indicator of hidden characteristics of the plant vacuoles, revealing differences otherwise invisible. One of the markers in our system, GFP-Chi, evidenced a clear morphological difference in the vacuolar system of guard cells of the three species.

Transformation and high efficient regeneration of transgenic plants from embryogenic calluses of Bingtang sweet orange [Citrus sinensis (L.) Osbeck] was reported. Embryogenic calluses were inoculated with Agrobacterium tumefaciens strain EHA105, harboring the binary Ti plasmid pROK II and carrying a neomycin phosphotransferase II (NPTII) gene, an intron β-glucuronidase (GUS) gene and the Arabidopsis APETALA1 (AP1) gene. Transformation treatment was with inoculation time of 30 min, co-culture of 3 d at 23 °C and supplementation of the co-culture medium with 2 mg dm^-3 acetosyringone (AS). Kanamycin (50 mg dm^-3) was effective to inhibit the growth of non-transformed calluses while it did not affect the transformed ones. The total number of transformed callus lines was 7 with 100 % embryo induction. High efficient regeneration of the transgenic embryos (88 % with 4-5 shoots per embryoid) was realized within 3 months. Integration of the transgene into the citrus genome was confirmed by histochemical GUS staining, polymerase chain reaction (PCR) analysis with AP1-specific primer and Southern blot hybridization with a 712 bp PCR fragment of AP1 as the probe.

Protocol was developed for high frequency in vitro multiplication of an endemic species, Zingiber rubens Roxb. The sprouted buds of the rhizomes were cultured on Murashige and Skoog (MS) medium supplemented with 6-benzyladenine (BA; 0.5-5.0 mg dm^-3), indole-3-acetic acid (IAA; 0.5-2.0 mg dm^-3), kinetin (KIN; 1.0-3.0 mg dm^-3), naphthaleneacetic acid (NAA; 0.5-1.0 mg dm^-3) and adenine sulphate (ADS; 80-100 mg dm^-3). MS basal medium supplemented with 3 mg dm^-3 BA and 0.5 mg dm^-3 IAA was optimum for shoot elongation. The elongated shoots (1-2 cm) were transferred to multiplication medium containing 2 mg dm^-3 BA, 1 mg dm^-3 IAA and 100 mg dm^-3 ADS. The multiplication rate remained unchanged in subsequent subcultures. Upon ex vitro transfer, 85 % of plants survived. Genetic stability of micropropagated clones were periodically evaluated at an interval of 6 months up to 30 months in culture using random amplified polymorphic DNA (RAPD) and inter simple sequence repeat (ISSR) analysis and genetic uniformity in all regenerants was confirmed.

The response of Arabidopsis thaliana plants to elevated sulfur dioxide could be related to their endogenous salicylic acid (SA) content and signaling. The wild type (WT, ecotype Columbia) and its mutant snc1 with high SA content, npr1-1 with a blockage in SA signaling, transgenic line nahG with low SA content and double mutant snc1nahG plants were exposed to 0.5 mm³ dm^-3 SO₂ for 3 h d^-1 for 14 d in a growth chamber. Under unstressed conditions, total SA contents in snc1 and npr1-1 were 7- and 2-fold higher than those in WT, respectively, but in nahG SA content was only 28 % of that in WT. The expression of nahG in snc1 plants decreased SA content to the WT level. Increased SA contents were observed in snc1, npr1-1 and WT after 12-h SO₂ exposure, whereas no major changes were detected in nahG and snc1nahG plants. The snc1 plants exhibited higher tolerance to SO₂ exposure than snc1nahG plants and especially nahG and npr1-1 plants according to plant biomass, total chlorophyll content and photosynthetic rate. The SO₂ exposure decreased net photosynthetic rate, maximum photochemical efficiency (F_v/F_m) and actual quantum efficiency of photosystem 2 (Φ_PS2). SO₂-induced oxidative damage in the tested plants was confirmed by increased malondialdehyde (MDA) content and electrolyte leakage. Increases in superoxide dismutase (SOD) and peroxidase (POD) activity, reduced glutathione (GSH) content and a ratio of reduced/oxidized glutathione (GSSG) might be responsible for the decreased contents of H₂O₂ and alleviation of oxidative injury in snc1 plants compared with other lines exposed to SO₂. These observations implied that endogenous SA content and signaling may play an essential role in plant responses to SO₂ stress.

The effects of the ectopic expression of a barley transcription factor (HvCBF4) under the control of a constitutive (maize Ubi1) or a stress-inducible (Arabidopsis RD29A) promoter in the abiotic stress response in rice (Oryza sativa L.) was investigated. The transformed plants were analyzed both at molecular and physiological level and the AtRD29A::HvCBF4 plants were further analyzed using the GeneChip® rice genome array under control conditions. Only the plants constitutively expressing HvCBF4 have shown increased survival to drought stress, but not to cold or high-salinity. These plants have also shown better photosynthetic capacity, as determined by chlorophyll fluorescence. Plants expressing AtRD29A::HvCBF4 did not show increased survival to any of the stresses applied. However in the GeneChip® microarray, these plants have shown up-regulation of many stress-responsive genes (> 400) as compared to non-transformed plants. Interestingly, RT-PCR analysis revealed not only differential gene expression between roots and shoots, but also between transgenic lines with the different promoters. Our results indicate that different HvCBF4 expression levels resulted in different transcriptomes and drought tolerance. Given that AtRD29A::HvCBF4 plants did not show increased tolerance to any of the imposed stresses, we may conclude that this promoter may be inappropriate for rice transformation aiming for enhanced abiotic stress tolerance.

To get insight into mechanism by which apple tree (Malus domestica Borkh.) regulates flowering, two apple flowering locus T (FT) homologues, MdFT1 and MdFT2, were isolated from the leaf cDNAs of cultivar Gala. The open reading frames (ORFs) of two MdFTs encoded 174 amino acids. The deduced amino acid sequence of MdFT1 and MdFT2 showed 94.3 % similarity to each other, while 72.6 and 76.0 % to AtFT protein, respectively. Semi-quantitative RT-PCR indicated their specific expression in leaves. Visualization of MdFT2-GFP fusion protein demonstrated its localization on membrane. Ectopic overexpression of either MdFT1 or MdFT2 in Arabidopsis significantly induced early flowering by activating the downstream flowering-related genes.

Partial cDNAs sequences for arginine decarboxylase (Pvadc), S-adenosylmethionine decarboxylase (Pvsamdc) and spermidine synthase (Pvspds) were isolated from the bean Phaseolus vulgaris using primers designed from conserved regions of enzymes belonging to plant species. Sequence analysis showed that the Pvadc, Pvsamdc and Pvspds genes were most closely related to the orthologous genes from Glycine max, Phaseolus lunatus and Pisum sativum, respectively. The expression patterns of the genes, together with that of ornithine decarboxylase (Pvodc), were analysed in young and mature leaves, stems, roots, root tips, petals, stigma, ovaries, filaments and anthers of bean plants. Pvsamdc was found to be expressed at similar levels in all tissues. The other transcripts showed tissue specific expression. Pvadc was barely expressed in petals and not at all in roots tips, Pvspds was mainly expressed in roots, stigma and filaments, and Pvodc was detected only in roots.

Universal (consensus) primers are those primers that have the ability to amplify the targeted region of DNA across a broad range of individuals in a certain group of organisms. In plants, such universal primers have been designed to target regions in the nuclear, mitochondrial or chloroplast genome. Among these three genomes, the chloroplast genome is the most suited for the design of consensus primers due to the lower rate of evolution and hence conservation of gene order and sequence of the genome among the different plant species compared to the other two genomes. Several molecular studies in plants have developed and used chloroplast-specific universal primers. In this review, I present some examples of the nuclear DNA-specific universal primers and discuss the features of the chloroplast DNA that make it the most suited for the design of such primers. I then refer to all chloroplast-specific primers developed so far and provide some examples of molecular studies and applications that made use of them.

Seedlings of Camellia sinensis were grown hydroponically for 30 d in order to study the effect of fluorine (F) on growth parameters, antioxidant defence system, photosynthesis and leaf ultrastructure. Fresh and dry mass, chlorophyll (Chl) content and net photosynthetic rate (P_N) decreased with increasing F concentration. Superoxide dismutase (SOD) activity decreased significantly, catalase (CAT) and guaiacol peroxidase (GPX) activities reached maximun under 0.21 and 0.32 mM F, respectively. Proline, malondialdehyde (MDA) and hydrogen peroxide (H₂O₂) contents increased significantly. These results suggested, that antioxidant defence system of leaves did not sufficiently scavenge excessive reactive oxygen species. The cell ultrastructure was not changed under 0.11-0.21 mM F, however, it was destroyed at 0.32-0.53 mM F. So tea plants tolerated F in concentration less than 0.32 mM.

This work was performed to find out if metal resistant clones of Salix viminalis L. are capable to achieve high resistance to the metals by regulating their net accumulation. Salix clones with low or high resistance in combination with low or high accumulation capacity of either Zn or Cd were cultivated from cuttings in nutrient solution. The investigation included leakage and uptake experiments using ⁶⁵Zn or ¹⁰⁹Cd and analysis of root cation exchange capacity (CEC). Some plants were pre-treated with unlabeled 0.5 μM Cd or 2.5 μM Zn 24 h prior to the experiments to induce possible tolerance mechanisms. To find out if the regulation was a metabolic process, experiments were also performed with 2,4-dinitrophenol (DNP). Clones with high resistance and low Cd accumulation had higher efflux of Cd compared to the other clones, in both untreated and Cd pre-treated plants. This indicates a constitutive property to lower Cd accumulation by high Cd leakage. Pre-treatment with 0.5 μM Cd diminished the Cd net uptake to a level near zero in all clones, likely to be due to decreased the Cd uptake. In contrast, resistant clones with high Cd accumulation had the highest root CEC, which may be used to bind up Cd in the free space. No clear regulation of Zn net uptake was found in Zn-resistant clones. Pre-treatment with Zn decreased the uptake of Zn into the free space in Zn-resistant clones. The resistant high-accumulating clones, however, showed the highest leakage of Zn in both untreated and pre-treated plants, a constitutive process not related to high accumulation. Neither the influx nor the efflux of Cd or Zn was affected by DNP indicating passive transport across the plasma membrane.