The changes in soluble proteins induced by Ce⁴⁺ were analyzed in suspension cultures of Taxus cuspidata using two-dimensional polyacrylamide gel electrophoresis. The ultrastructure of cells obviously changed at day 4 after addition of Ce⁴⁺. Large amount of nuclear DNA fragments of about 200 bp were observed. Thirteen protein spots were different between the cultures grown with and without Ce⁴⁺ at day 4 as well as at day 6 after addition of Ce⁴⁺.

Plasmid DNA (pChlCOD), containing the selectable hygromycin phosphotransferase hpt gene for hygromycin B resistance and the Arthrobacter globiformis codA gene for choline oxidase which catalyzes the direct conversion of choline to glycinebetaine, was delivered into rice plants using Agrobacterium-mediated gene transfer via scutellum-derived calli. Southern, Northern and Western blot analyses demonstrated that the foreign gene had been transferred, integrated into rice chromosomal DNA and expressed. Drought test indicated that glycinebetaine acts as an osmoprotectant and its production in transgenic rice plant helped the cells to maintain osmotic potential and increased root growth, and thus enhanced the ability of the plants to tolerate water deficit

An efficient protocol for shoot regeneration and genetic transformation was applied to root segments of a new Lotus corniculatus L. cultivar Bokor. The shoots, that regenerated on root segments, were inoculated with Agrobacterium rhizogenes A4M70GUS, and produced hairy roots, which on media with 0.2 mg dm^-3 benzylaminopurine, regenerated shoots. After rooting and acclimation, the transformed plants were planted in the experimental field. Their morphological traits were compared to controls. No signs of the rol genes phenotype were present. The transformants were significantly taller than controls, while there were no significant differences in the leaf area. The glucuronidase activity and the presence of uidA gene was demonstrated in transformed plants of T₀ and in seedlings of T₁ generations. It is concluded that A. rhizogenes could be a vector of choice for the transfer of desirable genes into the bird's foot trefoil genome.

We measured the stable deuterium isotopic composition of xylem sap, the shoot predawn and midday water potentials, and the leaf δ¹³C of Mediterranean shrubs Pistacia lentiscus, Globularia alypum and Rosmarinus officinalis in a south-oriented transect from a large (12 m tall) Aleppo pine tree, Pinus halepensis. We aimed to study the possibility of hydraulic lift from the deep roots of this pine tree to the shallow soil layers and its influence on these neighbour shrubs. These same traits were also studied in several individuals of the shrub Pistacia lentiscus growing with different types of neighbours: just shrubs, a small (3 - 4 m) pine tree, and the above mentioned large pine tree. The greater the distance from P. halepensis the plants grew, the higher xylem water δD, the lower the soil water content, and, the lower the predawn and midday water potentials were found. These results suggest the existence of an hydraulic lift from deep roots to shallow soil in this big tree. Further indication of this existence is provided by the improved water status of P. lentiscus (higher water potentials and δD, and lower δ¹³C and, therefore, lower water use efficiencies) when growing close to the big pine in comparison with the same shrub species growing close to small pines or just surrounded by other shrubs. Moreover, all these trends occurred in the dry summer season, but disappeared in the wet spring season.

Suspension culture was more efficient method for haploid production than anther culture. All analysed androgenic regenerants originating from embryogenic microspores in suspension culture of Aesculus hippocastanum L. had a haploid number of chromosomes (n=20), while 50 % of those derived from anther culture were diploids.

A field study was carried out to unravel the inter-specific differences in cotton for the partitioning of N, P, K, S, Ca, Mg, Na and Cl from the subtending leaves to the reproductive parts of Gossypium hirsutum, G. barbadense and G. arboreum at various developmental stages. Results revealed significant differences among the species for the various parameters studied. Overall there was a greater fresh and dry matter yield of various reproductive parts and subtending leaves of G. hirsutum and G. barbadense than G. arboreum, although the leaf photosynthetic rate was similar. Age-dependent increase in leaf area/leaf mass ratio indicated a greater partitioning of earlier acquired assimilates to the growth of reproductive parts. Results indicated greater partitioning of N, P, S and Ca during later reproductive growth (from boll production to its opening) in G. hirsutum and G. barbadense but during earlier reproductive growth in G. arboreum (from bud up to flower formation) as was evident by decreased subtending leaf/reproductive parts ratio. It is concluded that better N, P, S and Ca partitioning ability of G. hirsutum and G. barbadense at the onset of boll development played a major role in the better yield and good quality fiber characteristics.

Rootstocks for sweet cherry (Prunus canescens Bois) Camil GM 79 were grown in vitro on Murashige and Skoog (MS) medium, and on MS medium with double- and half-strength macroelements. All the media contained 4.4 μM 6-benzyladenine, 0.5 μM α-naphthylacetic acid, 0.3 μM gibberellic acid, 20 g dm^-3 sucrose and 7 g dm^-3 agar. The chemical analyses were monitored on day 0 and 40 of culturing in callus, stem and leaves. Fresh and dry mass of shoots increased linearly up to the end of culture. The highest fresh and dry masses and also the content of Ca and Mg were registered in shoots grown on half-strength MS medium.

Freshly-added iron only slightly affected the growth of iron-sufficient cells of the green alga Scenedesmus incrassatulus Bohl, strain R-83, but induced accumulation of malondialdehyde (MDA) in cells and excretion of MDA in the medium. These effects were stronger in response to Fe²⁺ as compared to Fe³⁺, but Fe³⁺ induced the release of more iron-binding chelators from these cells than Fe²⁺. Fe³⁺ added either in dark or in light induced release of equal concentrations of iron-complexing agents, part of which formed strong chelates with iron in the medium. Exogenously added hydrogen peroxide inhibited iron-induced release of chelators but the effect was removed by addition of the hydroxyl radical scavenger dimethylsulfoxide (DMSO). Malondialdehyde also inhibited the release of chelators. Release of chelators was induced in the absence of iron salts by photoexcited chlorophyll (Chl). The Chl-induced release was efficiently inhibited by singlet oxygen scavengers such as dimethylfuran, β-carotene, sodium azide and vitamin B₆, and stimulated in D₂O or DMSO. Exogenously added catalase inhibited the release more than added superoxide dismutase. The Fe³-induced release of chelators was also inhibited by scavengers of singlet oxygen, but was not affected by sodium azide and by ethanol. Hence both H₂O₂ and singlet oxygen were involved in induction of chelator release in the absence of iron in light. The induction of chelator release by iron in dark involved H₂O₂, but not singlet oxygen.

The effect of soil moisture on gas exchange and growth of an endangered species, Changium smyrnioides, was compared with a non-endangered species, Anthriscus sylvestris. The two species belong to the same family Umbellaceae. With the decrease of soil moisture, the net photosynthetic rate (P_N) and transpiration rate (E) decreased, while water use efficiency (WUE) increased, P_N and WUE of C. smyrnioides were lower than those of A. sylvestris, whereas E was higher than that of A. sylvestris. The biomass, leaf mass ratio (LMR) and leaf area ratio (LAR) of C. smyrnioides were lower than those of A. sylvestris. Under drought, biomass. LMR and LAR of C. smyrnioides decreased more steeply than those of A. sylvestris, whereas specific root length (SRL) of C. smyrnioides was higher, compared to that of A. sylvestris. The present study indicated that C. smyrnioides accumulated less biomass, and directed more biomass to roots than A. sylvestris.

A protein with an apparent molecular mass of 30 kDa that cross-reacts with barley glucanase antiserum was detected in healthy leaves of sorghum (Sorghum bicolor (L.) Moench). When sorghum leaves were infected with Exserohilum turcicum, the causal agent of leaf blight, the 30-kDa glucanase was substantially induced. The 30-kDa glucanase was partially purified from sorghum leaves using ammonium sulfate fractionation and anion exchange chromatography on DEAE-sephacel. The N-terminal amino acid sequence of the 30-kDa glucanase shows homology to glucanases of maize, barley, bean, soybean, tobacco and pea. The purified 30-kDa glucanase showed antifungal activity against Trichoderma viride.

Growth and activities of peroxidases, chitinases and glucanases were studied in order to evaluate the response of calli and roots of pink root-susceptible Allium cepa cvs. Valcatorce and T-412 and resistant A. fistulosum cv. Nogiwa Negi, to sterile culture filtrates of Phoma terrestris. Untreated calli and roots of A. fistulosum exhibited higher activity of peroxidases and glucanases than that of Valcatorce and T-412. Enzyme activities and growth of roots and calli were not affected in filtrate-treated A. fistulosum. The growth of calli and roots of A. cepa cultivars decreased significantly after exposure to P. terrestris filtrates while the peroxidase and glucanase activities increased. Peroxidase and glucanase activities were also enhanced in roots of Valcatorce bulbs grown in P. terrestris-inoculated soil as compared to healthy control plants. We conclude that a high constitutive activity of glucanases and perhaps chitinases might account for the resistance of A. fistulosum. The differential reaction (with respect to root growth) of pink root-susceptible and resistant materials to culture filtrates indicates that this in vitro-system might be useful for the screening of onion breeding lines.

An unknown brownish protein was purified by ammonium sulfate precipitation and DEAE-cellulose column and hydroxyapatite column chromatographies from pumpkin callus treated with a high concentration of 2,4-D. The apparent molecular mass and isoelectric point of the purified protein were estimated to be 38 kD and 4.6, respectively. The absorption spectra of the protein showed a shoulder at around 280 nm and a sharp peak at 405 nm. In order to determine what the purified protein is, a cDNA library of the callus treated with a high concentration of 2,4-D was immunoscreened with antiserum raised against the purified protein. The obtained positive cDNA clone encoded a thioredoxin h having a predicted molecular mass of 13 123 D and a predicted isoelectric point of 5.24, suggesting that the purified protein might be a trimer that was formed by oxidative polymerization of the thioredoxin h.

The water relations and stomatal conductances of three perennial plant species, Stipa tenacissima L., Anthyllis cytisoides L., and Retama sphaerocarpa (L.) Boiss., dominant on the upper slopes, mid-slopes and floor of a valley, respectively, in semi-arid south-east Spain, were investigated to test the hypothesis that differences in plant-soil water relations could account for the different distributions of each species in the catena. Diurnal measurements of water potential (Ψ_w), relative water content (RWC) and stomatal conductance (g_s) of leaves were made over one year. Leaf temperature, air humidity, wind-speed and incident quantum flux density were measured concurrently. Soil water content was determined gravimetrically at 0 - 5 cm and 15 - 20 cm depths. Measurements of Ψ_w, RWC and g_s were analysed according to meteorological conditions, based on the maxima for daily air temperature and atmospheric saturation water vapour deficit and on soil moisture content. The hypothesis that plant-soil water relations can explain the distribution of the three species along the catena from valley side to valley floor was rejected for Anthyllis and Stipa but confirmed for Retama.

This study deals with the effects of two cytokinins [kinetin (Kin) and N-(2-chloro-4-pyridyl)-N-phenylurea (CPPU)] and cytokinin antagonists [2-chloro-4-cyclobutyl-amino-6-ethylamino-1,3,5-triazine (ACK1) and N-(4-pyridyl)-O-(4-chlorophenyl)carbamate (ACK2)] in concentration of 1 μM on in vitro cultured Gypsophila. The application of Kin and CPPU stimulated bud opening and increased fresh and dry masses. Cytokinin antagonists reduced the number of sprouted buds and bud fresh and dry masses. In plants treated with CPPU the chloroplasts possessed well developed membrane system, which covered almost the entire chloroplasts volume. In ACK2 treated plants, the plastid apparatus in each cell was represented by two types of chloroplast in which the inner membrane system was differently organized. Cell wall adjacent chloroplasts possessed structure similar to the controls. In inner located chloroplasts part of thylakoids were semi-concentrically arranged and partially destructed.

Recent investigations on plant molybdenum-containing enzymes that include xanthine dehydrogenase (EC 1.1.1.204) and xanthine oxidase (EC 1.1.3.22), nitrate reductase (EC 1.7.1.1-3), aldehyde oxidase (EC 1.2.3.1), and sulfite oxidase (EC 1.8.3.1) are reviewed. The enzymes belong to closely related protein family and share common structural features. Special attention is being paid to the recently solved crystal structures their implications for the substrate binding and catalytic mechanism.

A field study was conducted to evaluate the drought tolerance of three sorghum [Sorghum bicolor (L.) Moench] cultivars, Gadambalia, Arous elRimal and Tabat, and quantify the physiological bases for differences in their drought tolerance. Water stress reduced shoot dry mass of Gadambalia, Arous elRimal and Tabat by 43, 46 and 58 %, respectively. The respective reduction in leaf area of the three cultivars was 28, 54 and 63 %. The reduction in net photosynthetic rate, stomatal conductance and transpiration rate due to water stress was lowest in Gadambalia and highest in Tabat. The leaf water potentials and relative water contents of Gadambalia under wet and dry treatments were similar, while those of Tabat were significantly reduced by water stress. The lowest and highest liquid water flow conductance was displayed by Tabat and Gadambalia, respectively. Drought tolerance in Gadambalia is associated with its smaller leaf area, higher liquid water flow conductance, and ability to maintain high leaf water potential, relative water content, stomatal conductance, transpiration rate and photosynthetic rate under drought stress.

In vitro regeneration of Melia azedarach L. was studied. Shoots were regenerated from calli initiated from leaflets of in vitro growing plants. The best medium for establishment of cultures was Murashige and Skoog (MS) medium with 4.44 μM benzylaminopurine (BAP) + 0.46 μM kinetin (KIN) + 16.29 μM adenine sulphate (ADE). Regenerated shoots were multiplied in MS + 0.44 μM BAP + 0.37 μM KIN + 3.26 μM ADE. Maximal rooting of 89 % was achieved by culture of regenerated shoots in MS + 12.26 μM indole-3-butyric acid for 3 d and subsequently in MS lacking growth regulators for 27 d. Rooted shoots were acclimatized and successfully transferred to soil.

A micro-propagating system based on the young stem node segments of Sophora flavescens Ait. (Fabaceae) was established. Murashige and Skoog (MS) basal medium supplemented with 8.88 μM 6-benzyladenine (BA) plus 2.69 μM α-naphthalene acetic acid (NAA) and that with only 5.37 μM NAA were found the best in promoting proliferation of shoots and induction of root, respectively. Percentages of shoot induction and number of shoot per explant were up to 93.4 % and 4.2 and rooting rate to 82.4 %, respectively. The segments of the regenerated shoots could be continuously induced to reproduce new shoots through subculture on the same medium in 30-d intervals and still kept this activity after being subcultured for 6 generations. After the regenerated plantlets were transplanted to field, they grew well, showing no any visible abnormalities.

Dimorphic seeds of Atriplex prostrata were removed from cold dry storage monthly over a one year period to test for fluctuations in seed dormancy and germination rate. For each seed type, four replicates of 25 seeds were exposed to four alternating night/day temperature regimes mimicking seasonal fluctuations in Ohio: 5/15 °C; 5/25 °C; 15/25 °C and 20/35 °C with a corresponding 12-h photoperiod (20 μmol m^-2 s^-1; 400 - 700 nm). We found a significant three-way interaction of seed size, temperature and month for both percent germination and the rate of germination. Large seeds showed the greatest germination at the 20/35 °C and 5/25 °C temperature regimes and small seeds at the 5/25 °C regime. Large seeds had greater germination at all temperatures as compared to small seeds. Large seeds had the fastest germination rates at 20/35 °C followed by 5/25 °C whereas small seeds had the fastest rates at 5/25 °C followed by 20/35 °C.

Overexpression of antifungal pathogenesis-related (PR) proteins in crop plants has the potential for enhancing resistance against fungal pathogens. Thaumatin-like proteins (TLPs) are one group (PR-5, permatins) of antifungal PR-proteins isolated from various plants. In the present study, a plasmid containing a cDNA of rice tlp (D34) under the control of the CaMV-35S promoter was introduced into tobacco plants through Agrobacterium-mediated transformation system. A considerable overproduction of TLP was observed in transformed tobacco plants by Western blot analysis. There was a large accumulation of tlp mRNA in transgenic plants as revealed by Northern blot analysis. Southern blot analysis of the DNA from transgenic tobacco plants confirmed the presence of the rice tlp gene in the genomic DNA of transgenic tobacco plants. Immunoblot analysis of intracellular and extracellular proteins of transgenic tobacco leaves using a Pinto bean TLP antibody demonstrated that the 23-kDa TLP was secreted into the extracellular matrix. T₂ progeny of regenerated plants transformed with TLP gene were tested for their disease reaction to Alternaria alternata, the brown spot pathogen. Transgenic tobacco plants expressing TLP at high levels showed enhanced tolerance to necrotization caused by the pathogen.

In the present study three species of Heritiera Aiton (Sterculiaceae) were characterized using 9 amplified fragment length polymorphism (AFLP) primer combinations and the genetic relationship among these three species was assessed, Nine AFLP primer combinations yielded 445 bands out of which 210 were monomorphic and 235 were polymorphic. Out of the 235 polymorphic bands 79 were present only in a single species. Among the total amplified bands 255 were shared between H. fomes and H. littoralis, 225 were shared between H. fomes and H. macrophylla and 306 bands were shared between H. littoralis and H. macrophylla. The cluster analysis showed H. littoralis is closer to H. macrophylla than H. fomes. The similarity between H. fomes and H. littoralis was higher than that of H. fomes and H. macrophylla. The present study indicates that H. littoralis is better classified as mangrove associate or back mangal than a true mangrove.

Effective protocol was established for micropropagation of the medicinal plant Eupatorium triplinerve Vahl through rapid axillary bud proliferation and ex vitro rooting. Murashige and Skoog (MS) medium fortified with 8.87 μM benzylaminopurine (BAP) and 2.46 μM indole-3-butyric acid (IBA) was the best for axillary bud proliferation and developed a mean of 8.1 shoots per node. Excision and culture of the node segments of the in vitro shoots on medium supplemented with the same concentration of growth regulators developed more than 30 shoots within 40 d. Shoot multiplication did not exhibit decrease in the number of shoots even at 7^th subculture. Dipping of the basal end of shoots in 2.46 μM IBA solution for 10 d induced roots and its transfer to small pots facilitated the survival of all rooted shoots (100 %). Ex vitro rooting by direct transfer of the shoots from multiplication medium showed 92 % survival.

Callus cells of potato (Solanum tuberosum L.) cv. Désirée were exposed to various subzero temperatures and examined for the freezing damage. In the cells subjected to -3 °C, plasma membranes appeared to be intact, while tonoplast seemed to be damaged and organelles to be swollen. After freezing at -6 °C, the damage became severe and plasma membranes were ruptured. After exposure to -10 °C, the damage was so severe that the cell organelles could not be recognised and cytoplasm became fragmented.

The regulation of proline accumulation in polyethylene glycol (PEG, -1.5 MPa) treated rice leaves was investigated. PEG treatment resulted in a decrease in relative water content, indicating that PEG treatment caused water stress in rice leaves. Proline accumulation caused by PEG was related to protein hydrolysis, an increase in ornithine-δ-amino- transferase activity, an increase in the content of ammonia, and an increase in the contents of the precursors of proline biosynthesis, glutamic acid, ornithine, and arginine. Results also show that abscisic acid accumulation is not required for proline accumulation in PEG-treated rice leaves.

The effects of aluminum on lipid peroxidation and activities of antioxidative enzymes were investigated in detached rice leaves treated with 0 to 5 mM AlCl₃ at pH 4.0 in the light. AlCl₃ enhanced the content of malondialdehyde but not the content of H₂O₂. Superoxide dismutase activity was reduced by AlCl₃, while catalase and glutathione reductase activities were increased. Peroxidase and ascorbate peroxidase activities were increased only after prolonged treatment, when toxicity occurred. The results give evidence that Al treatment caused oxidative stress and in turn, it caused lipid peroxidation.

The nature of nucleolar associate bodies in the meristematic cells of the root of Lupinus luteus L. was investigated using immunocytochemical methods, in situ hybridisation with light, confocal, and electron microscopy. The nuclear bodies of lupin proved to be structures containing fibrillarin and coilin, but devoid of rRNA and DNA, like animal coiled bodies (CBs). In lupin cells we have observed the occurrence of small nuclear ribonucleoprotein (snRNP) in the cytoplasm, in nucleoplasm, CBs and in nucleoli. This type of snRNP localisation pattern is in agreement with recently presented models of the small nuclear RNA cycle.

The effect phosphinothricin (PPT), an inhibitor of glutamine synthetase (GS), on proline accumulation in detached rice leaves was investigated. During 12 h incubation, PPT inhibited GS activity and induced accumulation of NH₄ ⁺, and accumulation of proline in the light but not in darkness. Proline accumulation caused by PPT in the light was related to protein hydrolysis, and increase in the contents of precursors of proline, ornithine and arginine. Abscisic acid accumulation was not required for proline accumulation in PPT-treated rice leaves.