The effect of 300 mM NaCl and wounding on the nicotinamide adenine dinucleotide (NAD) kinase, revealed by the guanosine triphosphate-dependent NAD reductase activity, was studied in two differently resistant bean cultivars using densitometric analysis of electrophoretic gels. In the presence of NaCl the total activity of NAD reductase was increased, in hypocotyls and root tips of resistant cultivar. The contribution of each of NAD reductase isoforms to the total activity was not significantly different between cultivars. Conversely, after wounding the hypocotyl, an increase could be observed in both cultivars and differences were demonstrated in the contribution of the different isoforms.

The effects of Cu²⁺ on growth, chlorophyll and other ion contents ofKoeleria splendens originated from Cu-contaminated soil have been investigated in nutrient solution. The most evident Cu²⁺ effects concern the root growth, especially the root length. Since in plants grown under lower Cu²⁺ concentrations (4 and 8 μM) root elongation, biomass, chlorophyll, Mg²⁺, Fe²⁺, Ca²⁺ and K⁺ content were increased compared with the control, the development of an adaptive mechanism ofK. splendens to Cu²⁺ is suggested. High Cu²⁺ concentration (160 μM) caused a significant reduction in root length and biomass as well as a decreased rate of chlorophyll biosynthesis. The reduction of growth can be correlated with the toxic effect of Cu²⁺ on photosynthesis, root respiration and protein synthesis in roots. 160 μM Cu²⁺-treatment had a negative influence on the concentrations of Ca²⁺, Fe²⁺, Mg²⁺ and K⁺ and a positive influence on the Cu²⁺ concentration in the plant tissues. Loss of nutrients similar to the senescence response suggests that excess of Cu²⁺ leads to the progressive senescence of the plants. Our results demonstrate the existence of an adaptive mechanism ofK. splendens under low Cu²⁺ concentrations, while high Cu²⁺ quantities cause disturbances in plant function.

Randomly Amplified Polymorphic DNA (RAPD) technique with 15 arbitrary primers was used to identify and reveal relationships of the accessions comprising 4 species ofLolium-Festuca complex. Altogether 252 RAPD markers were considered in statistical treatment, 60 of which could be identified as potentially taxon-specific. All analyzed taxa were fully distinguishable using RAPD markers.Lolium-Festuca relationships based on RAPD data were evaluated using cluster analysis (UPGMA) and principle coordinate analysis (PCO). The results of UPGMA as well as PCO performed on data pooled from all RAPD profiles support separation of the two generaLolium andFestuca.

The effects of supplying excess mineral salts, involving sodium as a cation and a range of counteranions, including chloride, on the growth and photosynthetic capacity of a salt susceptible bread wheat were studied. Plant performance was much more affected by the NaCl treatment than by the same concentration of either of the two component ions. With the exception of K⁺, other alkali metal chlorides also greatly inhibit plant growth and the electron flow through photosystem 2. The ranking of toxicity of these cations is Li⁺>Na⁺>K⁺. The synergistic effect of sodium (and other alkali and alkaline earth metals) and chloride shows that neither of these ions alone is responsible for salt stress induced damage.

An influence of some Random Amplified Polymorphic DNA (RAPD) reaction factors on resulting banding pattern and the ability of RAPD technique to detect DNA polymorphism among six economically important pea cultivars was tested. Relatively high level of DNA polymorphism among peas was observed, using polyacrylamide/urea gels and silver staining. Altogether 13 arbitrarily designed primers produced 313 amplification products. In addition 59 polymorphisms were found. These polymorphisms can serve as potential genetic markers. RAPD data were processed using cluster analysis and plotted as dendrogram. Each tested cultivar was clearly distinguished from the others. Moreover,Pisum sativum andP. sativum subsp.arvense cultivars were separated into 2 different clusters, according to their systematic relationships.

The effects of salinity (0, 50, 100, 150, and 200 mM NaCl) and heat-shock (42°C) and their interactions on germination, seedling growth, and some relevant metabolic changes of two cultivars (cv. Giza 155 and cv. Stork) of wheat (Triticum vulgaris L.) were studied. Germination studies indicate that plants tolerated salinity up to 100 mM NaCl. The lengths of roots and shoots and their water content, as well as fresh and dry matter yield of cv. Giza 155 seedlings remained more or less unchanged up to 100 mM NaCl and of cv. Stork up to 50 mM NaCl. Salinity induced progressive increase in soluble carbohydrates, soluble proteins and proline in cv. Giza 155 and in soluble proteins, proline and other free amino acids in cv. Stork. However, under the higher salinity levels, in cv. Giza 155 increase in soluble carbohydrates was accompanied by lose in other free amino acids, whereas in cv. Stork an opposite effect was obtained. Heat-shock treatment (42°C for 24 h) induced a significant decrease in the final germination percentage, the shoot and root lengths, fresh matter yield and the water content. The dry matter yield of the two cultivars was considerably increased as compared with the corresponding treatments with NaCl only. Heat-shock treatment resulted in a significant increase, in the amount of soluble carbohydrates and proline in salt treated seedlings of both cultivars. The pattern of changes in amino acids was opposite to that of soluble proteins, indicating that the increase in soluble proteins was at the expense of other amino acids in cv. Giza 155 andvice versa in cv. Stork.

DNA from 22 different species, accessions, cultivars and lines included in theSecale genus were analyzed by the polymerase chain reaction (PCR), using as primers five pairs of oligonucleotides derived from specific sequences. A total of 42 amplified bands were considered, and some of them appeared to be potentially useful as molecular markers for some of the analyzed groups. These amplified bands were used to generate molecular phenograms inside theSecale genus.

Molybdenum appliedin vivo to winter wheat (Triticum aestivum L., cv. Sadovo 1) grown on acid soil had cryoprotective effect. In Mo-treated plants the amount of digalactosyl diacylglycerol in the leaves increased during cold acclimation and that of monogalactosyl diacylglycerol remained relatively unchanged. An opposite tendency was observed in untreated plants. The most pronounced effect of freezing temperature on lipid changes was observed with respect to the different rate of phospholipid degradation in both kinds of plants. The amount of phospholipids at -5°C in Mo-treated plants increased while in untreated ones it significantly decreased. In general, the changes observed in Mo-treated plants corresponded to those shown for frost resistant plants.

The enzyme activities of the proline metabolic pathways were determined in control and satt-treated (140 M NaCl) calli derived from cotyledons of the domestic saltsensitive tomatoLycopersicon esculentum and the wild salt-tolerantL. pennellii. Glutamate, glutamine, asparagine, and aspartate levels increased in both genotypes under salt stress, while proline accumulation increased markedly only in the salt sensitive tomato. Activity of glutamine synthetase (GS) decreased in the salt-treated calli of the domestic species, whereas both NADH- and NADPH-glutamate synthase (GOGAT) activities increased; GS and NADPH-GOGAT decreased together in the salinized calli of the wild species. Decreasing ornithine levels were found due to NaCl in both tomato populations, while ornithine transaminase (OT) decreased in the wild type only. Increasing NADPH-Δ-pyrroline-5-carboxylate reductase (P5CR) and decreasing proline oxidase (Pro oxi) occurred in the salinized calli of the wild type. Conversely, Pro oxi and proline dehydrogenase (Pro dH) decreased highly in the salinized calli of the domestic population, while no significant changes in P5CR were found.

The cyanobacteriumSynechocystis PCC 6803 was grown photoautotrophically in an inorganic medium at constant growth temperatures of 20, 38 (control) or 43°C for 9 h. The up and down-shift of cultivation temperature decreased the growth as measured by culture absorbance and chlorophylla content. However, high temperature slightly increased the oxygen evolution while temperature lower than control inhibited oxygen evolution during the whole incubation period. The protein synthesis studied by¹⁴C-labeled protein declined under low temperature by about 50%. The fatty acid pattern is characterized as lacking in C₂₀/C₂₂ acids but containing large amounts of C₁₆ and C₁₈ polyunsaturated fatty acids, 16:2 and 18:3 in particular. The lower temperature increased the percentage of monounsaturated fatty acids while higher temperature increased the saturated fatty acid content in total lipids and lipid classes studied.

NADH specific glutamate dehydrogenase (GDH) activity was examined in roots and shoots of maize seedlings grown in half-strength Hoagland's solution containing NH₄NO₃ as sole nitrogen source under irradiance of 60 W m^-2 and temperature of 25±2°C. When 5,5'-dithio-bis (2-nitrobenzoic acid) (DTNB) was supplied to the assay mixture, it inhibited NADH-GDH activity in both roots and shoots, irrespective of whether the enzymes were extracted from light- or dark-treated roots and shoots. In each case the inhibition increased with the increase in DTNB concentration. At the maximum concentration of DTNB used (20 μM) the inhibition of shoot NADH-GDH was more pronounced than inhibition of root enzyme. This indicated differences in shoot and root NADH-GDH.

Cadmium (Cd) and kinetin (Kin) significantly affected the growth and contents of chlorophyll (Chl) and of soluble and reserve (hydrolysable) saccharides in sunflower plants. Cd-treated plants had lower contents of Chl and soluble saccharides and produced less dry matter than control (Cd-untreated) plants. Chla stability to heat (CSI) increased at all Cd concentrations. The same was true for Chlb stability (0-10 μM Cd). Spraying sunflower shoots with Kin solutions counteracted the deleterious effects of Cd. Kin application enhanced the Chla andb contents, Chla/b ratio, content of soluble saccharides and dry matter, and to less extent Chl stability. The relative role of Kin in affecting the parameters tested (as indicated by η² values) was predominant while that of Cd was subsidiary except for Chla stability. The role of Cd×Kin interaction was dominant for hydrolysable saccharides. Hence spraying shoots of plants grown under increasing Cd concentration with Kin can partially alleviate inhibitory effects of cadmium.

Cowpea (Vigna unguiculata L.) leaf discs incubated in the dark in solutions with CaCl₂ and benzyladenine (BA) maintained higher concentration of chlorophylls and proteins and higher activity of photosystem 2 (PS2) than controls. The effect of CaCl₂ and BA in combination was additive.

Glutamate dehydrogenase (GDH E.C. 1.4.1.2.4), glutamine synthetase (GS E.C. 6.3.1.2) and glutamate synthase (glutamine oxoglutarate amino transferase, GOGAT E.C. 2.6.1.53) activities, protein and organic nitrogen contents and growth of roots and shoots of maize seedlings raised in dark at 25±2°C in half strength Hoagland's solution containing different ammonium salts as source of nitrogen, were determined to assess the contribution of alternate pathways in ammonium assimilation. Ammonium nitrate or in some cases ammonium chloride appeared to be the best source for both root and shoot growth and for increase in protein, total nitrogen and the enzymes of ammonium assimilation. In roots, NH₄-nitrogen appeared to be assimilated by both GDH as well as GS-GOGAT pathways specially in the dark grown seedlings, while in shoots it was primarily by GS-GOGAT pathway.

Foliar application of gibberellin (GA₃) to patchouli (Pogostemon cablin Benth.) increased the plant height, number of nodes per plant, leaf fresh mass and photosynthetic pigment contents. The content of chlorophyll (Chl)b increased faster than that of carotenoids (Car), Chl (a+b) and Chla. This was reflected in a decline in Chla/b and Chl (a+b)/Car ratios. There was a GA₃ concentration dependent variation in the number of branches, leaves, total leaf area, and leaf area index. These growth parameters decreased over control values up to 250 g(GA₃) m^-3 and increased at 500 g(GA₃) m^-3 concentration. The patchouli oil yield varied from 2.4 to 2.6% of the leaf dry mass.

This study examined whether 'Risnod2' and 'Risnod27' non-nodulating mutants of pea (Pisum sativum L.) provided with increasing concentrations of nitrate could achieve a growth and nitrogen accumulation comparable to their parental N₂-fixing cv. Finale. In the cv. Finale, nodule number, nodule dry mass accumulation, total C₂H₂-reducing activity of nodulated roots (TAR) and estimated N₂ fixation were considerably inhibited at 5.0 and 10.0 mM root medium NO₃ ^- concentrations. In contrast a 0.63 mM level stimulated both the nodule dry mass and TAR. The cv. Finale N₂-fixing plants grown on 0 to 2.5 mM NO₃ ^- levels had higher shoot N concentrations than the Nod^- mutants, but within the 5.0 to 10.0 mM levels the Nod^- mutants approached or even overtopped the N concentration of the cv. Finale plants. Compared with a high positive correlation found in the Nod^- mutants, shoot N concentration in the cv. Finale was negatively correlated with the root medium NO₃ ^- concentration. The pattern of nitrogen content in shoot dry mass was very similar to that seen in the shoot dry mass accumulation. The Nod^- mutants grown on the 5.0 and/or 10.0 mM NO₃ ^- level had plant dry mass, shoot nitrogen concentration, shoot nitrogen content, and root/shoot dry mass ratio comparable with those of the nodulating cv. Finale grown on the same nitrate levels.

The effects of nitrogen deficiency on the growth and polyamine levels of suspensioncultured rice cells were investigated. Nitrogen deficiency markedly inhibited cell growth and resulted in lower levels of putrescine, spermidine and spermine than in the control culture supplied with nitrogen. The growth inhibition of rice cells induced by nitrogen deficiency could be recovered by the addition of a mixture of amino acids (glycine, L-aspartic acid, L-glutamic acid and L-arginine), but not by polyamines (putrescine, spermidine or spermine). Our results indicate that the decline of polyamine levels is not a factor causing growth inhibition of suspension-cultured rice cells under nitrogen deficiency.

Tephrosia purpurea Pers. was found to accumulate high proline content in dry habitat. The proline content was higher in shoots, especially in leaves, than in roots. Pod walls and young seeds showed the highest proline content. The proline content of young leaves was higher than that of mature and old leaves. During leaf senescencein vitro proline content increased rapidly upto 6 h and further decreased in leaves as well as in leachate. High proline content seems to be positively related with 'survival capability' of this plant.

In seedlings of the tropical tree speciesErythrina variegata Lam. andHardwickia binata Roxb. exposed to different acidic mist (H₂SO₄, pH 5, 3 and 2) for 5 d significant reduction in seedling growth, biomass accumulation and¹⁴CO₂ fixation were determined. In isolated chloroplasts a decrease in the activities of photosystem 2 and whole electron transport chain was observed only at pH 3 and 2, but no significant change in photosystem 1 activity was observed. SDS-PAGE analysis of crude leaf extracts of ribulose 1,5-bisphosphate carboxylase (RuBPC) indicated a significant loss of 55 and 15 kDa polypeptides at pH 2 inErythrina. The reduction in the RuBPC activity in seedlings grown under acidic mists correlated well with CO₂ fixation.

Rates of whole chain and photosystem 2 activities in chloroplasts isolated fromVigna unguiculata L. seedlings grown under ultraviolet-B (UV-B) enhanced radiation were less affected by 3, 6 and 9 mM CdCl₂ for 60 min at 0 °C in the dark than the rates in chloroplasts from control plants grown under normal irradiation. The results are in agreement with changes in contents of chloroplast 55, 47, 43, 33, 29, 27-25, 23 and 17 kDa polypeptides that were significantly lowered at 3, 6 and 9 mM CdCl₂ only in chloroplasts from control plants. On the other hand, in the simultaneous treatment of chloroplast isolated from control plants the UV-B supported the inhibitory effect of all applied concentrations of CdCl₂. The photosystem 1 activity was only marginally affected in the all experimental variants.

A field experiment was carried out to investigate the effects of presoaking the wheat grains (Triticum aestivum L.) in 33 or 66 mM NaCl and indolyl-3-acetic acid (IAA at 50 g m^-3), gibberellic acid (GA₃ at 100 g m^-3) or kinetin (100 g m^-3) on some tolerance criteria in wheat flag leaf at different stages of development. At various stages of flag leaf development pretreatment with 33 or 66 mM NaCl decreased degree of succulence (particularly 66 mM), relative growth rate, net assimilation rate, relative water content, K⁺ content and K⁺/Na⁺ ratio and at the same time induced accumulation of abscisic acid and Na⁺. In the majority of cases grain pretreatment with GA₃ or kinetin and to a lesser extent with IAA alleviated either partially or completely the deleterious effect of salinity on the above mentioned parameters.

Addition of different concentrations of heavy metal ions (Hg²⁺, Cu²⁺, Ni²⁺ and Pb²⁺) inhibited the photosystem 2 catalyzed electron transport activity (H₂O→p-benzo-quinone) of the cyanobacteriumSpirulina platensis. Hg²⁺ caused the inhibition in electron transport activity in very low concentrations compared to the other metal ions. Hg²⁺ at this low concentration specifically altered the spectral properties of phycocyanin of the phycobilisomes in the intact cells ofSpirulina, whereas other heavy metal ions were ineffective in this sense.