The lignin contents and anatomical structure of roots of wild cherry (Prunus avium L.) and pedunculate oak (Quercus robur L.) plantlets were compared to explain differences in response during transfer from in vitro to ex vitro conditions. Lignification of cell walls increased significantly in both oak and cherry roots during the period of acclimation and finally lignin content of root tissues of in vitro propagated plantlets reached the levels not significantly different from seedlings grown in soil. Later on when secondary tissues appeared, lignified secondary xylem constituted most of the tissues of both species. The most conspicuous interspecific difference in root structure was the presence of phi-thickenings in cortical layers just outer to endodermis in cherry roots cultivated ex vitro. Formation of phi-thickenings was avoided in vitro and their presence thus seems to be under environmental control. Suberised well established exodermis was present in roots of oak but not detected in those of cherry. Very early development of exodermis in oak roots, preceding suberisation of endodermis, was recorded in vitro but not in well aerated soil. While multilayered and well-developed cork occurred in oak, only thin walled and less suberised secondary dermal tissues were found in cherry.

The effect of applied arachidonic acid, prostaglandin (PGE₁) and various sterols and combinations of arachidonic acid + sterols, on flowering of Pharbitis nil were ascertained by using a tissue culture technique. It was found that arachidonic acid, PGE₁ stigmasterol, testosterone, cholesterol, stigmasterol + arachidonic acid, β-sitosterol + arachidonic acid and cholesterol + arachidonic acid all caused earlier flowering. Four inhibitors of prostaglandin biosynthesis (gentisic acid, acetylsalicylic acid, salicylic acid and oleic acid), inhibited flowering completely. The results confirm that the compounds tested could possibly play a role in the flowering of P. nil.

Corchorus olitorius plants treated by 5 μg cm^-3 of Cd, Pb, Al or Cu in hydroponic culture accumulated in leaves 190, 150, 350 and 325 μg g^-1(d.m.) of these metals, respectively, after 6 d of exposure. Exposure of Corchorus plants to tested metals resulted in a sharp rise in content of amino acids in leaf tissues, however the magnitude of accumulation was different from one metal to another. Presence of sulphur in the growth medium significantly increased uptake of Cd and Pb and cysteine (cyst) was more effective than K₂SO₄. Similarly, addition of salicylic acid (SA) in the growth medium significantly enhanced the ability of Corchorus plants to accumulate all these metals. Growth of Corchorus plants was significantly reduced by treatment with any of the four metals except Cu and added cyst, K₂SO₄ or SA alleviated the growth retarding effect of metals.

Thermotolerance of pearl millet (Pennisetum glaucum cv. ICMV-94133) and maize (Zea mays cv. Golden) was assessed at germination and vegetative stage. Final percentage of germinated seeds and rate of germination (number of days to 50 % germination) decreased due to high temperature (45 °C) similarly in the both species. In contrast, at the vegetative stage, high temperature (38/27 °C) caused a significant reduction in shoot dry mass of maize, whereas this attribute remained almost unchanged in pearl millet. Relative growth rate and net assimilation rate (NAR) increased significantly in pearl millet due to high temperature, but in contrast, in maize NAR was slightly reduced. Concentrations of N, P, and K in the shoots of both species increased at high temperature, but N accumulation was more pronounced in pearl millet than in maize. High temperature caused a marked increase in both shoot and root Ca²⁺ concentration in maize, but it did not affect that of pearl millet. S concentration in the shoots of maize decreased significantly due to high temperature, whereas that in pearl millet remained unaffected. Shoot Na⁺ concentration of both species was not significantly affected by high temperature. High temperature caused a significant increase in uptake of N, P, and K⁺ in pearl millet, but the uptake of Ca²⁺, Mg²⁺, Na⁺ and S remained unaffected in this species. In contrast, in maize, a significant increase in uptake of K⁺ and Ca²⁺, and a decrease in uptake of N, S, Mg²⁺, and Na⁺ were found at high temperature. Overall, maize showed lower tolerance to high temperature compared with pearl millet.

Three Bromeliaceae species of the medium Orinoco basin, Venezuela, were compared in their light-use characteristics. The bromeliads studied were two species of pineapple, i.e. the wild species Ananas ananassoides originating from the floor of covered moist forest, and the primitive cultivar Panare of Ananas comosus mostly cultivated in semi-shaded palm swamps, and Pitcairnia pruinosa, a species abundant in highly sun exposed sites on rock outcrops. Ananas species are Crassulacean acid metabolism (CAM) plants, P. pruinosa is C₃ plant. Plants were grown at low daily irradiance (LL = 1.3 mol m^-2 d^-1 corresponding to an incident irradiance of 30 μmol m^-2 s^-1) and at high irradiance (HL = 14.7 mol m^-2 d^-1 or 340 μmol m^-2 s^-1), and CO₂ and H₂O-vapour gas exchange and photochemical (q_P) and non-photochemical quenching (q_NP) of chlorophyll a fluorescence of photosystem 2 (PS2) were measured after transfer to LL, medium irradiance (ML = 4.1 mol m^-2 d^-1 or 95 μmol m^-2 s^-1) and HL. All plants showed flexible light-use, and q_P was kept high under all conditions. LL-grown plants of Ananas showed particularly high rates of CAM-photosynthesis when transferred to HL and were not photoinhibited.

Electrophoretic analyses of non-reduced and reduced seed storage proteins from Solanaceae and Cucurbitaceae species and cultivars were performed. High molecular disulfide bonded complexes between intermediary subunits of 11S globulins previously detected in Capsicum annuum cultivars, were found in Solanum melongena cultivars as well. The data obtained might be used for further elucidation of peculiarities of the 11S globulins in dicotyledonous plants.

For expression of MRJP1 - the most abundant protein of honeybee royal jelly - in plants, plasmid carrying the expression cassette composed of CaMV 35S RNA promoter, cDNA encoding MRJP1 with its native signal peptide, and nos3' as transcription terminator in binary vector pBin19 was prepared. The plasmid was introduced into tobacco (Nicotiana tabacum L. cv. Wi38) plants by Agrobacterium tumefaciens-mediated transformation. Transgenic F₁ and F₂ generation was grown from the seeds of the primary obtained transgenic tobacco plants. Immunoblot analyses of protein leaf extracts from transgenic plants showed expression of MRJP1.

Transgenic tobacco (Nicotiana tobacum) plants carrying the gene coding for potato virus A (PVA) non-structural P3 protein were prepared by inoculation with Agrobacterium tumefaciens. Seeds from self-pollinated flowers (T₁ generation) were collected. To estimate the effectiveness of vertical transfer of the introduced gene and usefulness of respective plant lines for further experiments, the T₁ generation was characterized by testing its ability to grow in the presence of kanamycin (Km) and by PCR of both neomycin phosphotransferase (nptII) and PVA P3 genes. Eight and ten of 29 lines showed Mendelian segregation of Km-resistant phenotype 3:1 and ≥15:1, respectively, the T₁ of eleven lines showed low Km resistance. Selected PCR-positive lines were tested for the presence of P3 mRNA. In most cases the transgene transcription was dependent on the presence or absence of Km in the plant growth medium. Prepared transgenic plants were furthermore tested for sensitivity to PVA and potato virus Y (PVY) infection. All of them showed identical symptom development as the non-transgenic control plants.

This study was conducted to examine the response of date palm (Phoenix dactylifera L., cvs. Barhee and Hillali) calli to water stress. Callus derived from shoot tip explants was inoculated in liquid Murashige and Skoog medium containing 10 mg dm^-3α-naphthaleneacetic acid, 1.5 mg dm^-3 2-isopentenyladenine, and 0 to 30 % (m/v) polyethylene glycol (PEG 8000) to examine the effect of water stress. After 2 weeks, callus growth, water content, and proline accumulation were assessed. Increasing water stress caused a progressive reduction in growth as expressed in callus fresh mass, relative growth rate, and index of tolerance. Both genotypes tested followed this general trend, however, cv. Barhee was more tolerant to drought stress than cv. Hillali. Increasing PEG concentration was also associated with a progressive reduction in water content and increased content of endogenous free proline.

This paper describes rapid propagation of Sesbania drummondii using nodal explants isolated from seedlings and young plants. The nodal segments proliferated into multiple shoots on Murashige and Skoog's (MS) medium supplemented with 22.2 μM benzyladenine. MS medium containing 2.2 and 4.5 μM thidiazuron induced 5 - 6 shoots per stem node from 3-month-old plants. Nodal explants when cultured on MS medium containing combinations of benzyladenine (8.8 and 11.1 μM) and indole-3-butyric acid (0.24 - 2.46 μM) or indole-3-acetic acid (0.28 - 2.85 μM) gave lesser number of shoots. Callus induced on cotyledonary explants when subcultured on 2.2 μM thidiazuron containing medium resulted in its mass proliferation having numerous embryoid-like structures. Indole-3-butyric acid (0.24 - 2.46 μM) was found suitable for root induction. In vitro regenerated plants were acclimatized in greenhouse conditions.

Tissue cultures of Armoracia rusticana L., both transformed with Agrobacterium rhizogenes and nontransformed, were screened for peroxidase activity. Most of the derived and tested strains exhibited 20 times higher activity [from 99 to 723 U g^-1(d.m.)] than the root of the intact plant [(30 U g^-1 (d.m.)]. The highest peroxidase activity was found in tumour culture growing on the medium without growth regulators. The influence of the addition of sugars and heavy metal ions in the medium on peroxidase production was tested. Increase in peroxidase activity was observed after cultivation of horseradish culture with cadmium, cobalt, nickel or lead ions.

The effects of treatment with NaCl (3, 100 and 300 mM) for 1, 2, 3 and 7 d on plant growth and ion accumulation were analyzed in 2-week and 8-week-old Annona muricata and A. squamosa plants. Fresh mass and root growth inhibition were directly related to the increase in salinity, particularly for A. squamosa. Two-weeks old seedlings were sensitive to 100 and 300 mM NaCl particularly after 7 d, whereas 8-week-old plants were shown to be more resistant to NaCl even at 300 mM NaCl. Na⁺ and Cl^- mostly accumulated in young leaves. Our results suggest that A. squamosa is more sensitive than A. muricata to salt stress and that older seedlings of both species are more tolerant than younger seedlings.

The effect of Cd (10, 100, and 200 μM) on tissue contents of macronutrients (N, P, K, Ca, Mg) and micronutrients (Fe, Zn, Cu, Mn) was investigated in hydroponically grown soybean (Glycine max) seedlings. Concentration changes of analysed elements observed against increasing Cd accumulation indicated that acute Cd-phytotoxic effect monitored through chlorophyll content was not a consequence of nutrient deficiency.

In order to establish an efficient system for in vitro plant regeneration of a short day plant Chenopodium rubrum L. and a long day plant Chenopodium murale L., optimum culture conditions for somatic embryogenesis were investigated. The effects of different growth regulators, their combination and their concentrations on somatic embryos induction in different explant types (root, hypocotyl, cotyledon and leaf) were tested. Somatic embryogenesis was induced in both plants on Murashige and Skoog (MS) medium supplemented with sucrose (3 %), agar (0.7 %) and 1 - 10 μM 2,4-dichlorophenoxyacetic acid (2,4-D) as the sole growth regulator. The largest embryogenic capacity was found in root explants of Chenopodium rubrum on 1 μM 2,4-D and in basal parts of cotyledons in C. murale plants on 10 μM 2,4-D.

A greenhouse experiment was conducted to assess the effect of 25, 50, 75, and 100 mM NaCl on growth, ion accumulation, seed yield, and seed oil content in 67-d-old plants of Foeniculum vulgare Mill. Increasing NaCl concentration caused a significant reduction in fresh and dry masses of both shoots and roots as well as seed yield. Na⁺ and Cl^- in both shoots and roots increased, whereas K⁺ and Ca²⁺ decreased consistently with the increase in NaCl concentration. Plants maintained markedly higher Ca²⁺/Na⁺ ratios in the shoots than those in the roots, whereas that of K⁺ /Na⁺ ratios remained almost uniform in both shoots and roots. Proline content in the shoots increased markedly at the highest NaCl concentration. Oil content in the seed decreased progressively with increase in salinity.

The effects of zirconium ascorbate (Zr-ASC), a water-soluble complex of Zr, were examined on wheat seedlings (Triticum aestivum L. cv. MV. 20). Hydroponically grown plants were exposed to 10, 33, 55, 100 and 550 µM Zr-ASC (Zr₁₀, Zr₃₃etc.). After 9 d of treatment inhibition of germination, retarded root and shoot growth, and increased activities of antioxidant enzymes (guaiacol peroxidase, ascorbate peroxidase, and glutathione reductase) showed that Zr-ASC was only harmful at and over a concentration limit of 100 µM. Chlorophyll (Chl) content of plants was only decreased by Zr₅₅₀. Zr-ASC at lower concentrations was beneficial for plant development: Zr₁₀ and Zr₃₃ enhanced root elongation, Zr₅₅ induced about 30 % increase in the total Chl content, while the activity of antioxidant enzymes was not elevated indicating that no oxidative stress was generated by the intracellularly accumulated Zr⁴⁺ ions.

Hydroponics were used to study the impact of acidity on growth, nutritive properties and metabolic changes in kikuyu grass (Pennisetum clandestinum Hochst). Four treatments (pH 6.0, 5.0, 4.0, and 3.0) were compared for effects on biomass, leaf and root length, crude protein, amino acid content and key enzymes of sugar metabolism. Reduction in biomass, root and leaf length, amino acid contents, glucose-6-phosphate dehydrogenase (G6PDH) and pyruvate kinase (PK) content was observed only at pH 3.0, in association with increased leaf proline content. Kikuyu grass is able to grow normally under mild acidity (down to at least pH 4.0).

We have cloned and characterized the expression of Crocus sativus AGAMOUS1 (CsAG1), a putative C-type MADS-box gene homologous to AGAMOUS (AG) from a triploid monocot species crocus (Crocus sativus L.). The typical domain structure of MIKC-type plant MADS proteins was identified. Phylogenetic analysis of the deduced amino acid sequence indicated that the isolated gene forms a clade with the AGAMOUS homologs from the monocots Hyacinthus orientalis and Phalaenopsis equestris. A differential splicing event altering the amino acid sequence at the C terminus was identified, leading to the formation of two mRNAs differing ten nucleotides in size. The presence of both differentially spliced transcripts was restricted only to mature crocus flowers and particularly to stamens and carpels.

Based on the NH₂-terminal sequence of three PR-10 isoforms previously identified in Lupinus albus leaves and a conserved amino-acid region in the PR-10 proteins from leguminosae, a pair of oligonucleotides was designed and used to amplify the corresponding cDNA fragment from a L. albus leaves cDNA library. A fragment of DNA of 200 bp was isolated from the polymerase chain reaction (PCR) mixture and subsequently used to screen the cDNA library. A cDNA coding for a PR-10 protein of 158 amino acid residues was cloned and sequenced. Subsequent studies involving Northern and Western blot analysis have shown that the PR-10 protein isoforms are differentially expressed during the development of the healthy lupin plant. High mRNA and protein contents were detected in roots and hypocotyls of both 7- and 20-d-old plants. In young leaves, the mRNA and protein contents were low and increasead in mature leaves. Tissue printing experiments with root sections suggest that the proteins are extracellular and are mainly associated with the vascular tissues in mature roots.

Effects of NaCl on growth in vitro and contents of sugars, free proline and proteins in the seedlings and leaf explants of Nicotiana tabacum cv. Virginia were investigated. The fresh and dry mass of the seedlings decreased under salinity. These growth parameters in leaf explants decreased at 50 mM NaCl and increased up to 150 mM NaCl and then decreased at higher level of salinity. Free proline content in both seedlings and leaf explants increased and polysaccharide content decreased continuously with increasing of NaCl concentration. Reducing sugars, oligosaccharides, soluble sugars and total sugars contents in both seedlings and leaf explants decreased up to 150 mM NaCl and then increased at higher concentrations of NaCl.

Various ecophysiological investigations are presented in Aldrovanda vesiculosa, a rootless aquatic carnivorous plant. A distinct polarity of N, P, and Ca tissue content per dry mass (DM) unit was found along Aldrovanda shoots. Due to effective re-utilization, relatively small proportions of N (10 - 13 %) and P (33 - 43 %) are probably lost with senescent leaf whorls, while there is complete loss of all Ca, K, and Mg. The total content of starch and free sugars was 26 - 47 % DM along adult shoots, with the maximum in the 7^th - 10^th whorls. About 30 % of the total maximum sugar content was probably lost with dead whorls. The plant was found to take up 5 - 7 times more NH₄⁺ to NO₃^- from a mineral medium. Under nearly-natural conditions in an outdoor cultivation container, catching of prey led to significantly more rapid growth than in unfed plants. DM of the fed controls was 48 % higher than in the unfed plants. The controls produced 0.69 branches per plant, while the unfed plants did not produced any. However, the N and P content per DM unit increased by 6 - 25 % in the apices and the first 6 whorls in the unfed variant, as compared to the fed controls. It may be suggested that carnivory is very important for Aldrovanda.

A simple and efficient protocol for high frequency plant regeneration of a grain legume grasspea (Lathyrus sativus L.) is described. Of different explant types tested epicotyl segments were most responsive. Murashige and Skoog's (1962) medium augmented with 17.76 µM 6-benzyladenine + 10.74 µM α-naphthaleneacetic acid showed the highest percentage of direct shoot regeneration. Among cultivars IC-120487 showed the highest regeneration frequency (80 %) with maximum shoot numbers (8.2 shoots per explant) and maximum average shoot length (4.1 cm). About 78 % of the regenerated shoots were rooted in half-strength MS medium containing 2.85 µM indole-3-acetic acid. After primary hardening the plantlets were established in soil with a survival rate of 75 %.

Temporal and spatial variations of shoot structural parameters, including shoot silhouette to projected needle area ratio, are very important, e.g., for the correction of leaf area index estimated by indirect methods. Here we bring few examples of their evolution within mountain spruce monoculture planted in two different densities.

The properties and kinetics of ATP and p-nitrophenyl phosphate (PNPP) hydrolysis activities of plasma membrane H⁺-ATPase from the two reed ecot ypes, swamp reed (SR) and dune reed (DR), were investigated. The pH optimum of the plasma membrane H⁺-ATPase in both reed ecotypes was similar but the sensitivity of the enzyme to the reaction medium pH seemed to be higher in DR than that in SR. Compared to SR, the DR exhibited a higher V_max value for ATP hydrolysis whereas the K_m value was almost similar in both reed ecotypes. The PNPP hydrolysis of the plasma membrane H⁺-ATPase was also studied in both reed ecotypes at increasing PNPP concentrations. K_m and V_max for PNPP hydrolysis showed great differences in the two reed ecotypes and in DR the K_m and V_max values were 2- and 10-fold, respectively, higher than those in SR. The ATP hydrolysis activity of the plasma membrane was markedly inhibited by hydroxylamine in both reed ecotypes, and the percentage inhibition of ATP hydrolysis rate seemed higher in DR than that in SR. In addition, the structure or property of the C-terminal end of the plasma membrane H⁺-ATPase were also different in the two reed ecotypes. These data suggest that different isoforms of the plasma membrane H⁺-ATPase might be developed and involved in the adaptation of the plant to the long-term drought-prone habitat.

Cadmium uptake, translocation and localization in maize roots and shoots at the tissue and cellular level were investigated. Metal accumulation in plant organs as well as symptoms of Cd toxicity were closely correlated with an increase in Cd concentration applied (5 - 300 μM). Most of the metal taken up was retained in roots, mainly inside the cells of endodermis, pericycle and central cylinder parenchyma. Accumulation of phytochelatins and related peptides also depended on Cd concentration in the nutrient solution.

The in vitro cultures of apple rootstock MM 106 produced the highest fresh mass (FM) when 0.1 mM B was included in the culture medium. By increasing B concentration of the culture medium from 0.1 to 6.0 mM, FM and contents of B, P, Ca, and Mg in explants increased, whereas K, Fe, Mn, and Zn contents decreased. SPAD units of leaves characterizing chlorophyll contents declined as B concentration of the culture medium increased from 0.1 to 6.0 mM.

Six pea (Pisum sativum L.) cultivars (Adept, Komet, Lantra, Olivin, Oskar, Tyrkys) were transformed via Agrobacterium tumefaciens strain EHA105 with pBIN19 plasmid carrying reporter uidA (β-glucuronidase, GUS, containing potato ST-LS1 intron) gene under the CaMV 35S promoter, and selectable marker gene nptII (neomycin phosphotransferase II) under the nos promoter. Two regeneration systems were used: continual shoot proliferation from axillary buds of cotyledonary node in vitro, and in vivo plant regeneration from imbibed germinating seed with removed testa and one cotyledon. The penetration of Agrobacterium into explants during co-cultivation was supported by sonication or vacuum infiltration treatment. The selection of putative transformants in both regeneration systems carried out on media with 100 mg dm^-3 kanamycin. The presence of introduced genes was verified histochemically (GUS assay) and by means of PCR and Southern blot analysis in T₀ putative transformants and their seed progenies (T₁ to T₃ generations). Both methods, but largely in vivo approach showed to be genotype independent, resulting in efficient and reliable transformation system for pea. The in vivo approach has in addition also benefit of time and money saving, since transgenic plants are obtained in much shorter time. All tested T₀ - T₃ plants were morphologically normal and fertile.

Cell cycle events in embryo axes of Norway maple (Acer platanoides L.) seeds were studied during dormancy breaking by flow cytometric analyses of the nuclear DNA content and by immunodetection of β-tubulin. Most embryonic nuclei of dry, fully matured seeds were arrested in the G₂ phase of the cell cycle. In addition, the lowest content of β-tubulin was detected in dry, mature seeds. Imbibition in water and cold stratification resulted in a decrease in the number of nuclei in G₂, and a simultaneous increase in β-tubulin content. In germinated seeds the content of β-tubulin was the highest and the number of cells in G₂ was the lowest. Both cell cycle events preceded cell expansion and division and subsequent growth of the radicle through the seed coat. The anatomical investigation has proved that the main reason for decrease in the number of nuclei in G₂ is mitosis, started with seeds germination (radicle protrusion). The activation of the cell cycle and the β-tubulin accumulation were associated with embryo dormancy breaking.