Plants of bean (Vicia faba L. cv. Calvor 103) were salt-stressed with NaCl and CaCl₂ in concentrations inducing soil osmotic potentials (ψ_soil) from 0 to -1.2 MPa and were sprayed with proline (8.7 µM) and glycinebetaine (8.5 µM) solutions. Bean plants respond to increasing soil salinity by decreased leaf relative water content and osmotic potential. Salinity decreased the contents of dry mass, chlorophyll, soluble and hydrolysable sugars, soluble proteins and enhanced content of total free amino acids, Na⁺, Ca²⁺ and Cl^-. The ratio of K⁺/Na⁺ was decreased on salinization. The membranes of leaf discs from salt-stressed plants appeared to be less stable under heat stress (51 °C) than that of unstressed plants. The reverse was true for discs placed under dehydration stress (40 % polyethylene glycol 6000). Proline and glycinebetaine application reduced membrane injury, improved K⁺ uptake and growth. Also both solutes increased chlorophyll contents.

A series of binary vector plasmids derived from the T-DNA of theAgrobacterium tumefaciens strain C58, carrying the five plant morphoregulatory genes 1, 2, 4, 5 and 6b in different combinations, was used in the transformation ofNicotiana tabacum leaf discs. Protein patterns of the transgenic tobacco analysed through SDS-PAGE have shown changes in the polypeptides with M_r: ∼120, 60, 55, 43 and 27 kDa (for tobacco with transgene 4); ∼60, 55, 43, 26-25, 21, 18 kDa (for tobacco with transgenes 1, 2 and 5); ∼70, 60, 26, 25, 18 kDa (for tobacco with transgene 5); ∼60, 55, 48, 26, 18 kDa (for tobacco with transgenes 4, 5, 6b); ∼60, 55, 22 and 18 kDa (for tobacco with transgene 6b); ∼60, 55, 43, 26 and 18 kDa (for transgenes 5, 6b); ∼60, 55, 22, 18 and 16 kDa (for transgenes 4 and 6b). All types of transgenic plants showed quantitative changes in protein content. Mendelian segregation ratio to kanamycin resistance in the progeny of transgenic tobacco clones in the R1 generation was 3∶1 except in transgenic tobacco carrying transgenes 1, 2 and 5.

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.

Carbon translocation was affected by shade in different tropical tree species differing in successional status and degree of shade tolerance. Plants of the early-successional shade-intolerant species Cecropia pachystachya and Schizolobium parahyba and of the late-successional shade-tolerant species Myroxylon peruiferum and Hymenaea courbaril were grown under full sun (FS) and natural shade treatments (NS) and assessed for [¹⁴C]-sucrose translocation. Most of the ¹⁴C was retained in the fed leaf after a 24 h translocation period. Under FS, the growing apical part of the plant was the most intense sink for most species. Shade affected growth and sink intensity differently in early and late successional species. Growth was more markedly affected in the early species. Whereas these continued to invest carbon into the growing apical part of the plant under shade conditions, the late successional species invested relatively more into other sinks.

The effect of acute ozone exposure on the stomatal conductance and leaf water content during rapid desiccation was examined in leaves of two tobacco cultivars, ozone sensitive cv. BelW3 and ozone tolerant cv. Samsun. The relative rate of stomatal closure was constant during leaf desiccation in cv. Samsun but decreased in cv. BelW3 in both ozonated and control plants. Ozone exposure increased the relative rate of stomatal closure and transpiration rate (measured on the following day) in cv. Samsun, but reduced the respective parameters in cv. BelW3. As a result, the plants of ozone-sensitive cultivar, treated with ozone, lost more water during desiccation than control plants.

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.

A reliable protocol for plant regeneration from mature embryo derived calli of nine barley (Hordeum vulgare) cultivars has been developed. The auxins 2,4-dichlorophenoxyacetic acid, picloram and dicamba proved effective in inducing callus from mature embryos of most of the barley cultivars. The induced primary callus was loose, friable and translucent. It ultimately yielded creamy white and compact callus after 2 - 3 transfers on fresh medium of the same composition. Callus induction and regeneration capacity were highly cultivar dependent. Addition of a high concentration of picloram (4 mg dm^-3) promoted regeneration in 3 cultivars (Tallon, Grimmett and Sloop). In cv. Arapiles, abscisic acid and betaine were crucial in generating morphogenic callus from the mature embryos. Plants regenerated from these calli were hardy and developed roots readily when transferred to hormone free medium.

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.

Recently, evidence has increased for both long- and short-distance transport of polyamines (PAs) in living organisms, but the mechanisms involved and physiological significance of PAs translocation are still not well understood. This review deals with various aspects of polyamine uptake and transport in higher plant tissues.

Expression of the β-glucuronidase (GUS) reporter gene driven by the CaMV 35S, rolC, nos and mas promoters was assessed in the tips of 12 independent clones of transgenic sugar beet (Beta vulgaris) roots. Three questions were addressed: 1) expression pattern specific for a given promoter, 2) expression pattern variability, and 3) relationship between gene expression and cell differentiation. Characteristic patterns of tissue-specific expression were distinguished for each promoter. Striking differences, however, were found between some clones, bearing the same construct. Statistical analysis of the pattern variability proved that the variability is significantly lower within the construct than between constructs. rolC-GUS clones exhibited the lowest and CaMV 35S clones the highest pattern variability. Comparisons between the four promoters showed consistent GUS activity in areas playing a key role in tissue determination (the elongation zone) where cells switch from frequent mitosis and mostly isodiametrical growth, typical for the promeristem, to rapid elongation and differentiation. All of the clones were highly GUS-positive in the elongation zone of stele. Activity was commonly localised in the stele of the maturation zone for CaMV 35S, rolC and mas-GUS clones. CaMV 35S-GUS clones were highly active in the promeristem.

The inoculation of mycorrhizal maize plants with three isolates of microaerophilic diazotrophic bacteria obtained from the mycelium of arbuscular mycorrhizal fungi associated with three grasses (Arrhenatherum elatius - bacterial isolate ARR, Agropyrum repens - isolate AGR and Poa annua - isolate POA) caused no increase in nitrogen content in plant biomass. The inoculation with bacterial isolate ARR resulted in the decreased plant growth. Bacterial isolate AGR decreased the percentage of the root length colonized by arbuscular mycorrhizal fungus Glomus fistulosum. The inoculation with both mycorrhizal fungus and isolate POA increased significantly the concentration of phosphorus in plant shoots compared to uninoculated control.

An attempt to reduce the production cost on tissue cultured plants, photoautotrophic culture of a high value orchid Dendrobium was established under CO2-enriched conditions. The shoot length and the number of leaves were almost equal in plantlets grown on medium with 2 % sucrose or without sucrose and under normal or enhanced (40 g m-3) CO2 concentration, whereas the fresh and dry masses were higher in cultures grown in sucrose containing media or under CO2 enrichment. Development of roots was observed only on media without sucrose, but CO2 enrichment did not have significant effects on in vitro rootings.

The effects of gibberellic acid (GA3) and N1-(2-chloro-4-pyridyl)-N2 phenylurea (4-PU-30) on maize seedling growth, photosynthetic parameters, and leaf protein composition were investigated. The agents used alone or in combination increased leaf growth and photosynthetic rate of the seedlings. Chlorophyll and total nitrogen contents in leaves as well as the quantity of individual protein fractions increased simultaneously. Sodium dodecyl sulfate polyacrylamide gel electrophoresis of soluble proteins (albumins and globulins) revealed quantitative differences between 4-PU-30-treated plants and the other experimental variants. They differed in polypeptide composition associated with changes in soluble proteins and amino acids. However, GA3 did not induce similar changes in polypeptide composition of soluble proteins.

Plants of Vigna mungo raised from seeds presoaked in salicylic acid (0.0, 0.01, 0.1 and 1.0 mM) and nodulated with the cowpea strain of Rhizobium leguminosarum were analysed 15 and 30 d after sowing. The foliar nitrate and nitrite contents were varying but soluble protein and total nitrogen contents were lower in treated than control plants. Nitrate reductase activity was increased at the two lower concentrations of 0.01 and 0.1 mM but was inhibited at the highest concentration used (1.0 mM). The number of nodules, their leghemoglobin and protein contents and nitrogenase activity of roots were reduced.

Decrease in seed viability and germination rate may be caused by biochemical changes associated with seed ageing. Different biochemical assays were conducted to investigate the changes occurring at the ageing of Bambusa bambos seeds. A reduction in the total content of food reserves such as sugars, proteins and lipids were recorded. Decreased activity of peroxidase, acid phosphatase, alkaline phosphatase were also noticed during accelerated ageing. A substantial increase in total free amino acids and the activity of amylases confirms the degradation of stored biomolecules in seeds during ageing.

Water and K⁺ fluxes were examined in detopped plants ofZea mays L. (cv. White Horse Tooth), which were grown and exuded on half-strength Long Ashton nutrient solution containing the appropriate concentration of Zn²⁺ at 20 °C. In light-grown plants, 100 and 500 μM Zn²⁺ increased both water and K⁺ fluxes in detopped maize plants whereas 1 000 μM Zn²⁺ inhibited both fluxes. In the dark-pretreated plants, 1 000 μM Zn²⁺ in the medium stimulated K⁺ flux. The fluxes of K⁺, Zn²⁺, Ca²⁺ and Mg²⁺ were usually higher in detopped plants than in intact ones. At 1 000 μM Zn²⁺ in the exudation medium, Zn²⁺ concentration was higher in the xylem exudate of dark-pretreated plants than in roots of plants maintained in light. The results are discussed in relation to the influence of Zn²⁺ on the membrane permeability and transport in plants.

Growth and Na⁺, K⁺, Cl^-, proteins, sugars and proline concentrations were measured in three triticale genotypes M2A, DF99 and Asseret grown on nutrient solution with or without 75 mM NaCl. In saline conditions, leaf area of the three triticales was reduced by 50 % and dry to fresh mass ratio increased. Total protein concentration was diminished by 10 %. K⁺ concentration decreased whereas Na⁺ and Cl^- accumulated in roots and shoots of salt-stressed plants. This ion accumulation was greater in roots of Asseret than in roots of the other triticales. Soluble sugar concentration increased in M2A and Asseret and decreased in DF99. Proline concentration increased in M2A and DF99 and decreased in Asseret. Osmotic adjustment was essentially realized by Na⁺ and Cl^- uptake. Non-reducing sugars and proline contributed too, but to a lesser extent.

Cytokinin content in xylem sap was higher in plants grown under local supply of fertilizers as compared to those grown under homogenous distribution of nutrients in soil. The separate assay of cytokinins in xylem exudate from split root system showed that roots, which were in contact with fertilizer mainly contributed to cytokinins transported from roots to shoots.

The decrease in inorganic phosphate concentration in bean (Phaseolus vulgaris L. cv. Złota Saxa) roots induced decrease in respiration rate. The decrease observed in ATP pool in phosphate deficient (-P) roots was greater than it would result from the decline in respiration and possible involvement of alternative pathway, suggesting an increased energy utilization for growth and ion uptake. Indeed, relative growth rate was higher in -P plants until 12 d of culture and later dropped to the rate similar to the control. Net nitrate uptake rate was higher in -P plants than in +P plants at the beginning of phosphate starvation, then during the prolonged culture it decreased rapidly in -P plants and after 19 d it was 8 times lower than that in the control. The decline in ATP production during prolonged phosphate starvation influenced NO₃ ^- uptake more than root growth.

Plants of peanut (Arachis hypogaea L.) were subjected to 7-d and 14-d waterlogging and sprayed with 10 and 100 mg 1^-1 of gibberellic acid (GA₃). Waterlogging decreased the leaf area (A), net photosynthetic rate (P_n), chlorophyll content (Chi) and temporarily the leaf water potential (Ψ_w) and increased stomatal diffusive resistance (r_s) of both leaf surfaces. Application of GA₃ increased A and P_n and significantly decreased the r_s of both leaf surfaces but did not affect Ψ_w or Chl. Thus GA₃ partially alleviated the effects of waterlogging on A, r_s and P_n.

Leaves of 15 - 30-d-old plants of sunflower and jute were harvested at 10.00 or 23.00 (local time) and measured immediately, or those harvested at 10.00 were incubated for one hour in sunlight either in water or 5 mM methionine sulfoximine (MSX) solution and then for three hours in dark either in water or 15 mM KNO3 solution. Nitrate feeding during dark incubation, in general, increased nitrate reductase (NR) and nitrite reductase (NiR) activities, and NADH and soluble sugar contents. Increase in tissue nitrate concentration in MSX fed but not in control samples suggested reduction of nitrate in dark. NADPH-dependent NR activity increased considerably upon feeding with nitrate in dark. Concomitantly, NADPH phosphatase activity was also increased in nitrate treated, dark incubated leaves. It is proposed that nitrate regulates dark nitrate reduction by facilitating generation of NADH from NADPH by NADPH phosphatase. High amounts of ammonia accumulated in MSX treated, but not in control leaves, upon dark incubation. Relative activities of NR and NADPH phosphatase, and amounts of soluble sugar and NADH were low in MSX fed samples compared to that of control. So, high amount of ammonia might partially repress NADPH phosphatase and consequently deprive NR of reducing equivalents.