Seedlings of two cultivars of zucchini (Cucurbita pepo L.) Courgette d'Italie (CI) and Courgette d'Alger (CA) were pre-treated with various concentrations of cadmium, copper and zinc for 30 d. High accumulation of heavy metals especially in the roots was showed. Peroxidase activity was affected according to the type of metal added, concentration, and the plant cultivar used. In leaves and roots of the CI control plants peroxidase activities were 50 and 17 % higher than in the CA control plants. Treatment with Cd (5 µg g^-1), Cu (200 µg g^-1), and Zn (500 µg g^-1) increased peroxidase activities in CA but decreased it in CI both in leaves and roots. Heavy metals tested lead also to some qualitative changes characterized by appearance of new isoforms of peroxidase. The results show the possibility to use the activities of peroxidase as biomarkers for Cd, Cu and Zn stresses.

Changes in the starch and sucrose contents, and the sucrose phosphate synthase, acid invertase, and starch phosphorylase activities were studied in the seedlings of salt sensitive and salt tolerant rice cultivars growing under two NaCl concentrations (7 and 14 dS m^-1) for 20 d. Under salinity, the starch content in roots declined more in salt sensitive cvs. Ratna and Jaya than in salt tolerant cvs. CSR-1 and CSR-3 and was unchanged in shoots. The contents of reducing and non-reducing sugars, and the activity of sucrose phosphate synthase was increased more in the sensitive than in the tolerant cultivars. Acid invertase activity decreased in shoots of the salt tolerant cultivars, whereas increased in salt sensitive cultivars. Starch phosphorylase activity decreased in all cultivars.

The content of glucose, fructose and saccharose as well as changes in the activities of enzymes involved in their biosynthesis and degradation were studied in tobacco plants infected with potato virus Y (necrotic strain) during the acute-infection period. Over the first part of this period, accumulation of saccharose, glucose and fructose was observed concurrently with decreased activities of the enzymes metabolizing saccharose, glucose and fructose (saccharases, saccharose synthase and hexokinases) and enhancement in the activities of enzymes synthesizing these carbohydrates (saccharosephosphate synthase, glucose-6-phosphate and/or fructose-6-phosphate phosphatases). The subsequent period was characterised by a reduction in both phosphatases that (together with just slightly raised saccharosephosphate synthase) could hardly produce enough sugars for the highly stimulated enzymes such as saccharases, saccharose synthase, and both kinases. Presumably for this reason, the previously increased content of sugars was considerably reduced to the level of control plants. The activities of glucokinase, fructokinase, saccharases and saccharose synthase were strongly increased at the culmination of virus multiplication and negatively correlated with the content of free glucose, fructose and saccharose.

The effects of copper on the activity of ascorbic acid oxidasc (AAO) in detached rice leaves under both light and dark conditions and in etiolated rice seedlings were investigated. CuSO₄ increased AAO activity in detached rice leaves in both light and darkness, however, the induction in darkness was higher than in the light. In the absence of CuSO₄, irradiance (40 μmol m^-2 s^-1) resulted in a higher activity of AAO in detached rice leaves than dark treatment. Both CuSO₄ and CuCl₂ increased AAO activity in detached rice leaves, indicating that AAO is activated by Cu. Sulfate salts of Mg, Mn, Zn and Fe were ineffective in activating AAO in detached leaves. CuSO₄ was also observed to increase AAO activity in the roots but not in shoots of etiolated rice seedlings.

Maltose was four times more effective than sucrose for androgenesis in anther cultures of an indica rice cultivar IR 43. Partial substitution of maltose by mannitol considerably enhanced the regeneration of green plants.

Genetic diversity analysis was carried out in chickpea accessions using restriction fragment length polymorphism (RFLP) and random amplified polymorphic DNA (RAPD) techniques. RFLP analysis using 26 Pst I sub-genomic clones on ten chickpea accessions in 130 probe-enzyme combinations detected polymorphism with only two clones. Pst I clones, CG 141 detected polymorphism in ICC 4918 and Pusa 209 while CG 500 detected polymorphism in Pusa 261, ILC 26 and in ILC 13326. These clones detected very few polymorphic markers. Analysis using 10 Eco RI clones on twelve chickpea accessions have shown better hybridisation signal and one clone detected polymorphism in Pusa 256. RFLP analysis of both cultivated and wild Cicer species using heterologous DNA probe Cab3C revealed polymorphism only in wild Cicer species (Cicer reticulatum L., JM 2100). RAPD analysis of 13 chickpea accessions which includes mutants of C 235 and E100Y showed greater degree of polymorphism with 1 - 5 unique DNA bands for all the accessions. Phylogenetic analysis of the RAPD data helped to group the accessions. C 235 and its mutants were found to be closely grouped while E100Y and its mutant E100Ym grouped apart. Desi and kabuli chickpea accessions however, could not be separately grouped.

The effects of abscisic acid (ABA) and water stress on senescence and enzyme activities of oxygen scavenging enzymes of detached rice leaves were compared. Exogenously applied ABA exhibited water stress-like effects by promoting senescence, by decreasing the activities of catalase, peroxidase, ascorbate peroxidase and superoxide dismutase. It seems that the effects of water stress on senescence and enzyme activities are possibly mediated through increased content of endogenous ABA.

Deterioration of membranes caused by lipoxygenase (LOX) activity under 10 µM PbCl₂ or 10 µM HgCl₂ was partially alleviated by the exogenous application of 100 µM salicylic acid (SA). In two cultivars of rice (Oryza sativa L. cvs. Ratna and IR 36), the presence of SA ameliorated the increased leakage of electrolytes, injury index, and the content of malondialdehyde caused by these heavy metals. Lead decreased H₂O₂ content whereas Hg increased it in both cultivars. Application of SA increased H₂O₂ in presence of Pb, while decreased it in presence of Hg. Both Pb and Hg decreased superoxide dismutase activity, while increased peroxidase activity. The activity of catalase was decreased by Hg but increased by Pb and SA reversed their effects. Thus, SA ameliorated the damaging effects of Pb and Hg on membranes.

Image analysis was used in studying stomatal morphology during acclimatization of tobacco plantlets to ex vitro conditions, 45 d after transfer leaf area was 15 times, and total number of stomata per leaf four times increased. During acclimatization stomatal density was decreased considerably on both leaf sides, and was compensated by an increase in stomatal sizes, e.g., in stomatal length and in stomatal area (both guard cells and pore). Elongation of stomata was increased indicating that the originally circular stomata of in vitro plantlets were changed into elliptical ones in ex vitro acclimatized plants.

Polymorphic DNA in complex genomes of agronomic crops can be detected using specific nucleotide and arbitrary primers and the polymerase chain reaction (PCR). Nineteen accessions representing 10 species of the wild perennial soybean were evaluated using 4 sets of specific primers and 3 sets of random amplified polymorphic DNAs (RAPD) primers. The potential of the RAPD assays was further increased by combining two primers in a single PCR. The fragments generated by the two assays discriminated 10 wild species by banding profiles. The size of the amplified DNA fragments ranged from 100 to 2100 base pairs. The resolved PCR products yielded highly characteristic and homogeneous DNA fingerprints. The fingerprints were useful not only for investigating genetic variability but also for further characterizing the wild soybean species by detecting inter- and intra-specific polymorphisms, constructing dendrograms defining the phylogenetic relationships among these species, and identifying molecular markers for the construction of genetic linkage maps. Furthermore, unique markers distinguishing particular species were also identified. Thus, it is expected that PCR will have great relevance for taxonomic studies.

Potato (Solanum tuberosum L. cv. Bintje) was transformed with a cDNA clone encoding an osmotin-like protein. Transgenic and non-transgenic in vitro plants were subjected to NaCl for 3 weeks. The shoot and root development was slightly affected by salinity indicating that the salt condition used was a mild stress. The endogenous proline content of the osmotin-like transformed clone only raised slightly as compared to the non-transformed genotype, where a marked increase in proline content could be observed as a result to salt stress. These data provide evidence for the involvement of osmotin-like proteins in the mechanisms of salt tolerance in potato plants.

High frequency shoot regeneration from cotyledons excised from 4-d-old seedlings of Brassica campestris L. cv. M 27 and Brassica juncea (L.) Czern. cv. Pusabold was achieved on Murashige and Skoog's (MS) medium supplemented with 1.0 mg dm^-3 N⁶-benzyladenine (BA) and 3 % (m/v) saccharose. Rooting occurred simultaneously with shoot formation on the medium containing 1.0 mg dm^-3 BA and 0.5 mg dm^-3 1-naphthaleneacetic acid. Cultures of cotyledon, cotyledon derived non-differentiating calli and differentiated calli with shoots and/or roots were analysed at different intervals for isozyme patterns of esterase and peroxidase. With the BA-induced development of shoot and/or root from non-differentiating callus, some conspicuous isozymes appeared which indicates the involvement of these isozymes in root and shoot development rather than in induction of morphogenesis in callus.

The effect of benzothiadiazole (BTH) on protein synthesis was studied in sugar beet plants. Extracellular proteins induced by 0.025 % BTH were examined and their pattern was compared with that induced by sodium salicylate, chitosan, paraquat, AgNO₃, and by tobacco necrosis virus. BTH induced synthesis of at least 9 acidic and 6 basic proteins; three of them appeared as acidic chitinase isozymes, three as acidic β-1,3-glucanase isozymes, three as basic chitinase isozymes, and one as a basic β-1,3-glucanase isozyme. One of the basic chitinase isozymes was found also in control plants. The most of the newly formed proteins was also induced by the other inducers under study regardless of the necrotic or symptomless reaction of plants. The benzothiadiazole proved to be an efficient inducer of proteins in sugar beet.

Influence of pre-sowing chilling treatments to seeds on seed germination and accumulation of osmotics in Indian mustard [Brassica juncea (L.) Czernj & Cosson] under NaCl stress was investigated. Germination was 100 % in water soaked non-chilled (control) seeds upto 100 mM NaCl, whereas it was upto 200 mM NaCl in chilling treated seeds. Pre-sowing chilling treatments to seeds for 5, 10 and 15 d also enhanced the dry mass of 6-d-old seedlings, and concentrations of saccharides and amino acids. The alleviation of NaCl stress by pre-sowing chilling treatments was also associated with decrease in Na⁺ and proline accumulation and a slight increase in K⁺ and Ca²⁺ contents of seedlings.

Leaf isoenzymes of Pericopsis mooniana from twenty-one trees at forest plantation were evaluated for their use in identification of elite trees among heterogeneous population. Trees were grouped morphologically, before leaf extracts were separated by one-dimensional polyacrylamide gel electrophoresis. Isoenzyme analysis were carried out for peroxidase, esterase, alcohol dehydrogenase, formate dehydrogenase, acid phosphatase, aspartate aminotransferase, isocitrate dehydrogenase, malate dehydrogenase, leucine aminopeptidase, phosphoglucoisomerase, phosphogluconate dehydrogenase, phosphoglucomutase, and shikimate dehydrogenase. From the thirteen enzymes studied only four gave distinct banding patterns. Level of significance of appearing particular band for each enzyme of a given category was investigated using χ²-test, followed by cluster analysis for categorization. The isozyme type A of formate dehydrogenase showed promising results that could be used for differentiating trees of categories investigated.

The responses of barley (Hordeum vulgare L.) lines with rebuilt chromosomes 5, 6 and 7 to reduced nitrogen nutrition were evaluated in juvenile growth stages. The material included two series of duplications (D) produced in the short arm of chromosome 6 and of chromosome 7, and in the long arm of chromosome 5 and of chromosome 6; their parental translocation lines (T) - from which analyzed duplications were derived and a standard karyotype cv. Bonus as a control. The translocation lines have break points located in 6_S and 7_S, or 5_L and 6_L. Only the lines with duplicated segments of the short arms of satellited (6 and 7) chromosomes exhibited an improved tolerance to reduced nitrogen supply. No changes relative to cv. Bonus were observed in the T-lines. More tolerant D-lines showed lower stimulation of the root development. Obtained results suggests that the adaptability factors for the low N tolerance at the vegetative growth stage of barley are located in the short arms of 6 and 7 chromosomes.

Hydrolysis of 13S globulin, the main storage protein in grains of common buckwheat (Fagopyrum esculentum Moench), proceeds in at least two phases during germination. The first stage, involving a limited proteolytic cleavage of the protein, is associated with increased activity of proteases having maximum activity at pH 7.6. The second stage, involving further hydrolysis of the partially cleaved protein, starts after 12 h of imbibition. During this phase, activity of proteases increased and activity maximum shifted to pH 5.6. Nevertheless, 13S globulin retains its antigenic identity till the emergence of radicle and plumule. Thus, it may not be the major source of amino acids utilized by the germinating seed during the initial stages of imbibition.

Responses of Ceriops roxburghiana Arn. leaves to the sodium chloride, applied at different concentrations (ranging from 100 to 600 mM), has been evaluated. Total amino acid content decreased with increasing NaCl concentration, while the protein content increased significantly up to 400 mM concentration and decreased thereafter. Total sugar content decreased at concentrations beyond 400 mM. Proline and glycine betaine were accumulated with increasing NaCl concentration. Protease and ATPase activities were increased whereas proline oxidase activity were decreased with increasing salinity. Peroxidase and malate dehydrogenase (NADH-MDH) activities did not significantly differ under various NaCl concentrations.

The ability of peanut (Arachis hypogaea L.) to grow at high concentrations of NaCl may be due to the alteration in gene expression. SDS-PAGE analysis has revealed that plants grown under NaCl showed induction (127 and 52 kDa) or repression (260 and 38 kDa) in the synthesis of few polypeptides. In addition, nine different esterase isoenzymes were detected in embryos of seeds germinated in 105 mM NaCl, whereas only five of them were detected in the embryos of untreated seeds. On the other hand, in the cotyledons, the esterase pattern was not affected by NaCl concentration. The esterase patterns of both stems and leaves were less influenced by NaCl in comparison to those of roots. The lipid contents, and fresh and dry masses were increased up to 45 mM NaCl and decreased at higher concentrations.

Collection of the T-DNA tagged lines of Arabidopsis thaliana have been created by Agrobacterium-mediated root transformation. Transgenic lines produced by this method have been screened for morphogenic mutations. A flower mutation with increased number of stamens and carpels (scaf1) was identified. This mutation has similar but weaker phenotype than the known mutant superman. Two mapping procedures, with visible and molecular markers, were used to locate scaf1 flower mutation. Genetic analysis showed that this mutation is located on chromosome 3 near gl1 gene. It is probably one of the SUPERMAN epigenetic alleles.

Leaf tissues of 38 genotypes, derived from four accessions, of the hexaploid species Helianthus tuberosus (2n=6x=102) responded to growth regulators (BA, NAA) chiefly by forming callus, while aventitious organogenesis or somatic embryogenesis were induced occasionally. A remarkable regeneration frequency (about 30 %) was achieved only from leaves of genotype HTPI-15. Explants of many regenerated plants of HTPI-15 subjected to a second culture cycle in vitro displayed a high morphogenetic potential (regeneration frequency > 90 %). White globular structures were initiated on the adaxial surface of these leaves without a callus phase. Somatic embryogenesis was asynchronous and embryoids, of different developmental stage, were simultaneously detected on each explant. Although many embryos developed single or malformed cotyledons or germinated precocciously, without the differentiation of a complete root system, phenotypically normal plants were regenerated after rooting on regulator-free half-strength MS medium.

Heat shock proteins (HSPs) ranging in molecular masses from 14 to 110 kDa were induced in embryonic axes of germinating Cajanus cajan (L.) Millspaugh seeds after exposure to 40 °C for 1 or 2 h. At 45 °C, there was a marked decline in synthesis of HSPs. A close relationship was observed between HSPs induced and the growth of the germinating seeds. Pretreatment of germinating seeds at 40 °C for 1 h or 45 °C for 10 min followed by incubation at 28 °C for 3 h led to considerable thermotolerance (45 °C, 2 h) and the recovery of protein synthesis.

In the leafstem moss Mnium affine two superoxide dismutase (SOD) isoforms were found in chloroplasts and two in mitochondria. Four other isozymes were probably cytosolic and two of them had high activity and thermostability and were very sensitive to H₂O₂. On the other hand, one of the mitochondrial isoenzymes was very sensitive to high temperature. The activity and thermosensitivity of SOD was considerably dependent on calcium and zinc ions. The effect was different for the individual isoforms and related to their subcellular distribution. Calcium ions predominantly activated and stabilized one cytosolic and the mitochondrial SODs, while zinc ions influenced one chloroplastic and two cytosolic SODs.