Spirodela polyrhiza L. Schleid. plants developed anthocyanin (AC) on the abaxial frond surface when grown on Hoagland nutrient solution diluted 1:≥40; AC content was maximum at 1:80 dilution. Till 1:20 dilution there was no or very little AC formation. The formation of AC seems to rely on the availability of excess carbon skeleton in relation to nitrogen in plants. Thus, addition of saccharose to 1:20 diluted medium resulted in a concentration-dependent AC formation. Also fructose, glucose, mannitol, and sorbitol induced AC synthesis. Conversely, urea and ammonium nitrate, when added to the 1:80 diluted medium, suppressed the AC formation. Omission of micronutrients from the growth medium led to the formation of a little amount of AC whereas polyethylene glycol and Cd treatments were ineffective. AC produced under starvation (7 d on distilled water) did not get turned over upon the transfer of plants to nutrient sufficient (1:5 diluted medium) conditions indicating that AC formed does not serve as a reversible C-reserve.

Increasing salinity of growth medium induced a reduction in growth and transpiration rate. The concentrations of chlorophylls and carotenoids were increased in most cases in broad bean leaves while in pea plants they remained more or less unchanged with the rise of salinization up to 80mM NaCl. Thereabove a significant decrease in these contents was observed. A stimulation of the net photosynthetic rate of pea was observed at the lowest levels of NaCl but at the highest levels inhibitory effect was recorded. In broad bean all salinization levels inhibited photosynthetic activity, but dark respiration of both plant species was stimulated. The content of Na⁺ in the roots and shoots of both species increased at increasing salinity. In broad bean, Ca²⁺ concentration in shoots and K⁺ and Ca²⁺ contents of roots increased at increasing salinization, while in pea plants, the content of K⁺ and Ca²⁺ was almost unaffected by salinity. Salinity induced an increase in the content of these ions in pea roots. Mg²⁺ content in shoots and roots of both broad bean and pea decreased at increasing salinity except in roots of pea, where it was generally increased.

Eight-day-old bean plants, grown in a nutrient solution, were sprayed with 10^-5, 10^-4, 10^-3, and 10^-2 M atrazine. The lipid changes in primary and trifoliate leaves were studied 6 d after the herbicide application. The atrazine treatment inhibited the growth of the trifoliate leaves, and decreased photosynthetic and transpiration rates, the stomatal conductance, and the total lipid content. Atrazine treatment increased 16:0 and 18:3 acids and decreased trans-3-hexadecenoic and 18:2 acids in the phospholipids. The herbicide also increased 16:0 and 18:1 acids in glycolipids and decreased 18:3 acid in monogalactosyl diacylglycerols and digalactosyl diacylglycerols. In most cases the marked changes in fatty acid composition of the main lipid classes were observed at 10^-4 and 10^-3 M atrazine.

The effect of combinations of different concentrations of copper (Cu) and mercury (Hg) ions with different constant temperatures (T) onPhaseolus vulgaris plants was studied. Criteria investigated included shoot and root length, dry mass, chlorophyll content (Chl) and stability index (CSI), and contents of soluble (SS) and hydrolysable saccharides (HS), soluble proteins (SP) and total free amino acid (AA). Each of the factors (T, Cu and Hg) significantly affected the parameters tested with exception of T effect on Chlb content as well as on Chla/b ratio. Bifactorial interactions (T×Cu) or (T×Hg) were also significant, except the interaction (T×Hg) in shoot elongation, Chlb content and Chla/b ratio. Statistical treatment of the data lead to three findings: (1) temperature was dominant in affecting CSIa, shoot AA and root SS, (2) Cu and Hg had the predominant effect on growth parameters and Chl content, and (3) interactions (T×Cu and T×Hg) were dominant in affecting CSIb, shoot SP, and root HS.

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.

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.

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 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.

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.

Changes in ribonucleases (RNases) and glucose-6-phosphate dehydrogenase (G6P DH) activities, their content and subcellular localisation were studied in relation to virus multiplication in susceptible (cv. Samsun) or resistant (transgenic breeding line NCTG 83) tobacco plants infected with the potato virus Y^N (necrotic strain of PVY). Activities of RNases and G6P DH from diseased susceptible tobacco plants were markedly increased during the experimental period and significantly correlated with the multiplication curve of the PVY^N. In contrast, the activities of RNases and G6P DH were not changed after PVY inoculation of resistant breeding line NCTG 83 producing the CP mRNA of PVY. Changes in the content and in the subcellular localisation of RNases and G6P DH isozymes were also determined in mesophyll protoplasts isolated from healthy as well as PVY^N infected plants of both cultivars by differential centrifugation of broken protoplasts on day eight post inoculation (the culmination of multiplication curve of PVY and enhanced activity of both enzymes). The chloroplasts fraction from infected protoplasts showed an enhanced content of RNases (192.4% when compared with that from healthy control ones), and of G6P DH (174.4 %). The cytosol fraction from infected protoplasts contained slightly enhanced levels of G6P DH (117.4 %) and considerably enhanced levels of RNases (141.7 %). No significant differences in the activities, contents and subcellular localisation of RNases and/or G6P DH isozymes were observed in the resistant line NCTG 83. This is in accordance with no detectable contents of PVY.

The Vigna radiata L. plants were grown in greenhouse at moisture content of sand (SMC) of 12.0 ± 0.5 %. At flower bud initiation stage, i.e. 45 - 50 d after sowing, the SMC was decreased to 3.5 ± 0.5 %, and the effects of applied potassium (0, 2.56 and 3.84 mmol dm-3) were studied. During water stress, K-fed plants maintained higher leaf water potential and relative water content (RWC) of leaves and nodules and lower osmotic potential as compared to untreated plants. The proline content was higher in nodules than in leaves showing their difference in degree of stress. A partial recovery was found after re-irrigation. When subjected to drought, carbon was accumulated in the leaves and declined in nodules and roots. K-fed plants showed higher C and N content in stem, roots and nodules than untreated plants. The content of K significantly increased in stem and nodules in K-fed plants, irrespective of SMC. Dry masses of different plant parts were also increased in K-fed plants.

Detached wheat shoots (ear with peduncle and flag leaf) were incubated for 4 d in a solution containing 1 mM RbCl and 1 mM SrCl2 as well as 10, 40 or 160 µM NiCl2 and CoCl2. The phloem of some plants was interrupted by steam-girdling the stem below the ear to distinguish between xylem and phloem transport. The phloem-immobile Sr flowed mainly to the leaf lamina and to the glumes via the xylem. The Sr transport was not sensitive to steam-girdling. In contrast, the phloem-mobile Rb accumulated during the incubation time mainly in the stem and the leaf sheath. The Rb transport to the grains was impaired by steam-girdling as well as by elevated Ni and Co concentrations in the incubation solution indicating that Rb was transported via the phloem to the maturing grains and that this transport was affected by the heavy metals. Ni was removed more efficiently from the xylem in the peduncle than Co (but far less efficiently than Rb). It became evident that the two heavy metals can also be transferred from the xylem to the phloem in the stem of wheat and reach the maturing grains via the phloem.

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.