Electrophoretic analyses of non-reduced and reduced seed storage proteins from 34 cultivars of Capsicum annuum L. were performed on two gel systems. On the basis of clearly expressed difference in electrophoretic profiles of non-reduced proteins, the investigated cultivars were divided into two groups. The two observed phenotypes were genetically determined and related with intermediary subunits of 11S globulins and/or their oligomers.

Multiple shoots in Arachis hypogaea L. could be induced from the de-embryonated cotyledons (DC), embryo-axes (EA) and mature whole seeds (MWS) in MS medium supplemented with different levels of benzylaminopurine (BAP). DC was the most suitable explant with 57.9 % induction and more than 40 shoots per explant in 31.6 % of cases. Though EA and MWS had high percent induction at or above 30 mg dm^-3 BAP, only 10 - 14 shoots per explant were observed. In DC, multiple shoots were confined to the proximal end and in EA they originated from the axillary bud region. Histological studies on DC confirmed the origin of shoots from the region of attachment with the embryo. Shoots could be rooted in MS medium containing 2 g dm^-3 charcoal and 200 mg dm^-3 casein hydrolysate. Sixty percent of the rooted plantlets could be established in the field.

The germination of lentil seeds was gradually reduced when seeds were exposed to temperature of 30 or 40 °C, either alone or combined with 0.1, 0.2 or 0.3 M NaCl or 34.1 % (m/v) PEG 8000, during 6 -12 h imbibition. [³⁵S]-methionine incorporation in 12 h imbibed lentil axes also decreased with increasing NaCl concentration at 20 and 40 °C, whereas at 30 °C only 0.3 M NaCl treatment partially inhibited protein synthesis. An analysis of newly synthesized proteins by 1-D SDS PAGE, showed that the expression of most polypeptides decreased following increasing stress. Among these, low molecular mass heat-shock proteins declining, higher in 40 °C treated axes than those treated at 30 °C, supports the hypothesis that at this temperature maximal level of expression of these proteins was achieved.

Wheat seedlings of a salt tolerant cultivar were grown hydroponically in presence and absence of 100 mM NaCl. Roots were harvested, and the plasma membrane (PM) fraction was purified. PM ATPase required a divalent cations for activity (Mg > Mn > Ca > Co > Zn > Ni > Cu), and it was further stimulated by monovalent cations (K > Rb > NH₄ > Li > choline > Cs). The pH optima were 6.0 and 5.6 in absence and presence of 25 mM KCl, respectively. The enzyme was sensitive to vanadate and DCCD but insensitive to azide, oligomycine and nitrate. The enzyme displayed a high preference for ATP but was also able to hydrolyze other nucleotide tri- and diphosphates. The enzyme activity showed a simple Michaelis-Menten kinetics for the substrate Mg²⁺-ATP in both control and salt exposed roots. The polypeptide patterns of control and salt stressed PM fractions, detected by SDS-PAGE, were very similar. NaCl substantially reduced the PM ATPase specific activity, whereas it had little effect on the apparent K_m for Mg²⁺-ATP. Since the root PM ATPase of salt sensitive and resistant genotypes responded similarly to salinity stress, it seems unlikely that the mechanism of salt tolerance in wheat is primarily based on differences in PM ATPase characteristics.

Role of lipid peroxidation and antioxidative enzymes (catalase, peroxidase, superoxide dismutase, ascorbate peroxidase and glutathione reductase) in water stress-promoted senescence of detached rice leaves was investigated. The senescence was followed by measuring the decrease in protein content. Increased lipid peroxidation was closely correlated with senescence in water stressed leaves. Decrease in superoxide dismutase activity was evident 8 h after beginning of water stress. However, decreased catalase, peroxidase, and ascorbate peroxidase activity was observed only when senescence was observed. Glutathione reductase was not affected by water stress. Free radical scavengers retarded water stress-enhanced senescence.

Seed storage proteins of ten maize inbred lines were investigated by sodium dodecyl sulfate polyacrylamide gel electrophoresis. In addition, fourteen isozyme loci representing nine isozyme systems were analysed. Salt-soluble protein fraction contained a large number of proteins (30 - 40 bands) of different sizes with genotypic differences among the ten inbred lines. The methionine-rich 10 kD zein showed differential expression in the ten inbred lines with different migration rates on the SDS-PAGE. This polypeptide was completely absent in the inbred line G221D. Among nine of the inbred lines, eight of 14 isozyme loci were polymorphic and six were monomorphic resulting in seven unique fingerprints.

Anatomical changes of leaf epidermes of tomato plants (Lycopersicon esculentum Mill. cv. INCA 9) submitted to water stress in the preflowering stage were studied. 20 d after germination, plants were subjected to three treatments: 1) 100 % of evapotranspired water was applied every day, 2) from 100 up to 10 % of evapotranspired water was applied every day, and 3) water supply was completely suppressed. Trichome density was similar in apical, middle and basal zones, and adaxial and abaxial leaf surfaces. Stomatal density and length, and epidermal cell length and width had similar values on the same leaf surface, but the values were higher on the abaxial than on the adaxial leaf surface. The water deficit had little effect on number of trichomes, length and width of epidermal cells and length of stomata, and decreased the stomatal density especially on adaxial surface.

Field study revealed that species diversity index of the community was 0.597. The data of interspecific association index of Alhagi graecorum and each of its associates, Chenopodium murale, Glinus lotoides and Malva parviflora, were 0.35, 0.41 and 0.33, respectively. Therefore, a net negative association and low diversity among the species were the main characters of the community. Laboratory experiments verified the role played by competition and allelopathy in this community organization. The bioassay results indicated that A. graecorum exhibited phytotoxic activity on the tested species. Accordingly, water-borne allelopathic compounds may be released from A. graecorum into the environment and suppress the growth of its associates where they were not able to compete with A. graecorum in the field, so the latter species become dominant.

Fusarium oxysporum f. sp. albedinis, the bayoud disease agent of date palm, grows on a mineral medium containing the cell walls of date palm roots as a sole carbohydrate source. The growth and development of pathogen under these conditions was related to the production of extracellular cell wall-degrading enzymes (CWDE): cellulases, polygalacturonases, polygalacturonate transeliminases, and pectinmethylesterases. The mycelial growth and the sporulation of pathogen were higher in the presence of cell walls of susceptible cultivars (BFG, JHL, BSK) than in the presence of those of resistant cultivars (IKL, SLY, BSTN). After 8 d of fungal culture, the activity of CWDE was equal whatever is the origin of the cell walls (resistant or susceptible cultivars). After 16 d of culture, the activity of these CWDE was higher when the parasite was cultivated on the cell walls of the susceptible cultivars than on those of the resistant cultivars. A positive correlation was observed between CWDE activities and the growth and the sporulation of F. oxysporum after 16 d of culture. These results clearly show a relation between the susceptibility/resistance of the cell walls of the roots of the date palm to the parasitic CWDE and the susceptibility/resistance of the cultivars.

Maize (Zea mays L.) seedlings were exposed to osmotic stress, and alcohol dehydrogenase (ADH) activity and abscisic acid (ABA) concentration were determined. The osmotic stress increased ADH activities in both roots and shoots, whereas the increase was 2-fold greater in roots than the shoots. The stress also increased ABA concentration in both roots and shoots and the increase was greater in the roots than in the shoots.

In an open-top chamber experiment located in a mountain stand of 14-years-old Norway spruce (Picea abies [L.] Karst.), trees were continuously exposed to either ambient CO₂ concentration (A), or ambient + 350 µmol mol^-1 (E) over four growing seasons. Respiration rates of different woody parts (stem, branches, coarse roots) were measured during the last growing season. The calculated increase in the respiration rate related to a 10 °C temperature change (Q₁₀) was different in stem compared to branches and roots. Differences between the E and A variants were statistically significant only for roots in the autumn. Stem maintenance respiration (R_Ms) measured in April and November (periods of no growth activity) were not different. The stem respiration values (R_s) were recalculated to a standard temperature of 15 °C to estimate the seasonal course. The obtained R_s differed significantly between used variants during July and August. At the end of the season, R_s in E decreased slower than in A, indicating some prolongation of the physiological activity under the elevated CO₂ concentration. The total stem respiration carbon losses for the investigated growing season (May - September) were higher for A (2.32 kg(C) m^-2 season^-1) compared to E (2.12 kg(C) m^-2 season^-1). The respiration rates of the whorl branches (R_b) were lower compared with the stem respiration but not significantly different between the used variants. The root respiration rate was increased in E variant.

Induction of rooting in the microshoots of Plumbago zeylanica was achieved on halfstrength basal Murashige and Skoog's medium supplemented with 0.25 mg dm^-3 indole-3-butyric acid. Rooting was totally inhibited when the microshoots were cultured in vitro under continuous light, however, maximum percentage of microshoots rooted when incubated in continuous light for 4 weeks before transfer to the rooting media. Peroxidase activity increased markedly during root induction indicating a key role of peroxidase in rooting of microshoots of Plumbago zeylanica in vitro.

A simple systems for in vitro storage of health asparagus germplasm was developed. High percent (90 %) of shoots cultured in a standard multiplication medium were maintained viable in vitro at 5 °C in darkness for 12 months. This percent was decreased to 60 % when cultures were stored for 18 months. At normal temperature, shoots and callus cultures also survived for 1 year under osmotic stress on medium containing 40 g dm^-3 mannitol.

The activities of peroxidase, polyphenol oxidase and superoxide dismutase was significantly lower in roots and leaves of NaCl stressed radish (Raphanus sativus L.) plants. Addition of triadimefon to the NaCl stressed plants increased peroxidase, polyphenol oxidase and superoxide dismutase activities, and thereby ameliorated the negative effect of NaCl stress.

Two maize lines differing in drought resistance were grown at different drought stress induced by polyethylene glycol (PEG 10 000) solutions with osmotic potentials of -0.20, -0.40 and -0.80 MPa in the semipermeable membrane system. During the five days soil water content decreased (from 0.43 to 0.29, 0.25 and 0.23 g cm^-3 for three PEG solutions, respectively) as well as leaf water potentials (ψ_w; from - 0.54 to -0.76, -1.06 and -1.46 MPa). These values were not significantly different between the investigated lines, indicating that a controlled and consistent soil moisture stress was achieved. Soil drying induced an increase in the ABA content of leaves and xylem of both lines and the effects on stomatal conductance were greater in drought susceptible line (B-432) compared to drought resistant line (ZPBL-1304). To test possible difference in stomatal sensitivity to xylem ABA between lines and to assess any ABA vs. ψ_w interaction, roots were fed with 10, 50 and 100 mmol m^-3 ABA solutions in another set of experiments. These results showed that manipulation of xylem ABA affected stomata of both lines similarly. Comparison of stomatal sensitivity to drought-induced and applied ABA demonstrated that drought treatment affected stomata of investigated lines by differentially increasing their sensitivity to xylem ABA, thus confirming an interaction between chemical signalling and hydraulic signalling.

The effect of foliar-applied glycinebetaine (GB) on chloroplast ultrastructure, the amount of chlorophyll and proteins and ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBPCO) activity in stressed tomato leaves were analysed. Initial, and total activity and activation state state of RuBPCO were also measured. RuBPCO activities, chloroplast area, and the number of plastoglobuli remained unaffected, while the relative area of starch granules increased in GB-treated, salt-stressed tomato leaflets. Under drought-stress, the relative area of plastoglobuli increased upon GB application. The primary effect of GB was, however, the increased protein and chlorophyll content.

Field experiments with Glycine max (L.) Merr. cv. Ludou 11 and Ludou 4 were conducted to evaluate changes in photosynthetic rate, antioxidative enzyme activity, soluble protein, chlorophyll (Chl) and carotenoid (Car) contents in relation to leaf senescence during seed filling period. Photosynthetic rate, soluble protein content, catalase and peroxidase activities were the highest at 25 days after flowering (DAF). Chl a, Chl b and Car contents reached the maximum at 15 DAF and rapidly decreased after 33 DAF.

Watermelon (Citrullus lanatus [Trumb.] Mansfeld cv. Early Star), was used as scion grafted onto three cultivars of pumpkin (Cucurbita pepo L. cvs. Brava, Shintoza and Kamel) used as rootstocks and ungrafted Early Star plants were used as control. The rootstocks showed a high capacity for N uptake and transport to the scion where N reduction and assimilation improved growth of the scion in grafted plants with respect to the control.

The influence of potassium sulfate, abscisic acid (ABA) and indole-3-acetic acid (IAA) solutions on xylem exudation rate and potassium efflux from the apical cut end of root tips of intact maize (Zea mays L. cv. Dnepropetrovskaya) seedlings was studied. Foliar application of 5 mM K₂SO₄ considerably stimulated the exudation rate. The application of ABA and IAA (1 mM) also induced a high rate of xylem exudation, K⁺ efflux being simultaneously increased.

In Solanum nigrum, the initiation of root primordia occurred directly on stem explants or microshoots cultured on half strength MS medium supplemented with 1 mg dm^-3 indolebutyric acid (IBA), indole-3-acetic acid, or naphthalene acetic acid, IBA being most effective. Initiation of shoot primordia occurred on B5 medium supplemented with 0.5 mg dm^-3 benzylaminopurine (BAP) or kinetin; BAP was more active. During shoot formation, the increased content and the expression of new isoenzymes of peroxidase (POX), esterase and malate dehydrogenase was found. On the other side, expression of new indophenol peroxidase isoenzyme was detected during root formation. Organogenesis of S. nigrum has no effect on glutamate oxaloacetate transaminase and glutamate dehydrogenase content. Differential expression of POX could be detected between basal and upper side of explants.

Activities of host ribonucleases and glucose-6-phosphate dehydrogenase were studied in three cultivars (Monosvalof, Steffi and Rimini) of sugar beet differing in their resistance to beet necrotic yellow vein virus (BNYVV). No differences were found in the susceptibility of cultivars to BNYVV between mechanically inoculated and Polymyxa betae (a natural fungal vector of the virus) infected plants, but the culmination of reproduction curves of BNYVV in mechanically inoculated plants was observed one week earlier than in plants inoculated by means of P. betae. The activities of ribonucleases corresponded with virus multiplication. In roots, activities of ribonucleases reached a maximum at day 7; in leaves, maximum activity was found at day 21 in cv. Monosvalof, and at day 14 in cv. Steffi. The relatively resistant cultivar Rimini showed much lower activities. The activity of glucose-6-phosphate dehydrogenase was only slightly increased at the time of culmination of the BNYVV reproduction curve in cvs. Monosvalof and Steffi.

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.