Rhizobacteria belonging to Bacillus sp. were isolated from the rhizosphere of green gram (Vigna radiata). Seed inoculation with the rhizobacteria showed stunting effect on root growth whereas four Bacillus strains caused stimulation of shoot growth at both 4 and 7 d of observations. Coinoculation of some Bacillus strains with effective Bradyrhizobium strain S24 resulted in enhanced nodulation and plant growth of green gram. The shoot dry mass (ratio to uninoculated control) varied from 1.32 to 6.33 at day 30 and from 1.28 to 3.55 at day 40 of plant growth. Nodule promoting effect after 40 d of plant growth was observed with majority of Bacillus strains except for MRS9 and MRS26. Maximum gains in nodulation, nitrogenase activity and plant growth were observed with Bacillus strains MRS12, MRS18, MRS22 and MRS27 after 40 d of plant growth, suggesting the usefulness of introduced rhizobacteria in improving crop productivity.

Effects of two cytokinin antagonists - 2-chloro-4-cyclobutyl-amino-6-ethylamino-1,3,5-triazine and N-(4-pyridyl)-O-(4-chlorophenyl)carbamate - on bud break and outgrowth in single nodes from two Rosa hybrida cultivars differing in their apical dominance were studied. The compounds were applied at three different concentrations separately or in combination with benzyladenine. Cytokinin antagonists reduced the number of the sprouted buds in both cultivars at different extent. Their effect was strongly dependent on both concentration applied and culture period duration. The replacement of anticytokinins with benzyladenine in the medium resulted in overcoming of the bud break suppression. Both compounds significantly inhibited bud outgrowth as well.

Treatment of rose shoots with 50 µM acibenzolar-S-methyl (BTH) resulted in increased protection against Diplocarpon rosae. This was accompanied by the induction and accumulation of a set of extracellular proteins as shown by SDS-PAGE and 2D-PAGE. Some of these proteins have been identified as PR-1, PR-2, PR-3 and PR-5 proteins by immunoblot analysis probed with tobacco antisera against PR-1c, PR-N, PR-Q and PR-S protein. Most of the extracellular proteins activated by BTH were also induced and found to accumulate in leaves upon infection with Diplocarpon rosae. However, their accumulation was much more pronounced in BTH-pretreated leaves than in water-pretreated leaves upon a challenge inoculation with D. rosae, particularly, the 15 kD PR-1, 36 and 37 kD PR-2 proteins. They may be more important in the expression of disease resistance.

A study was conducted to evaluate in vitro techniques for germplasm preservation of wild species of Arachis. Nodal segments excised from in vitro-grown plants of A. retusa, A. macedoi and A. burchellii were used to examine the effects of explant position and age of the donor plant. Explants were excised from plants maintained in culture for 30, 60, 90 or 180 d, numbered I - V from top to bottom and cultured on MS medium supplemented with 2.7 µM NAA or different BAP concentrations (0, 4.4, 13.2 and 22 µM). The age of the donor plant has not influenced the responses of the four genotypes studied. In contrast, shoot regeneration ability was significantly affected by the original explant position, decreasing from top to bottom. In media supplemented with different BAP concentrations, multishoot formation was induced from apical segments at low frequencies (10 - 20%) and segments of all positions originated calluses at the explant basis after 30 d of culture. The culture of nodal segments in the presence of 2.7 µM NAA as the sole growth regulator is recommended for the multiplication of in vitro collections of wild groundnut species in order to avoid callusing and adventitious shoot formation.

Phenolic compounds from leaves and roots of infected and healthy cocoyam clones resistant (RO1075), tolerant (RO1043), and susceptible (RO1157) to Pythium myriotylum were quantified and tested for their in vitro fungitoxicity on the causal agent of the cocoyam root rot disease. All clones, infected or not, have phenolic compounds showing fungitoxic activity. The phenolic content of the tolerant and susceptible clones is less than that observed in the resistant one meanwhile in the resistant clone RO1075, a large increase in phenolic content is observed particularly in the roots during attack by pathogen.

Effects of four culture media on callus induction, regeneration and number of plants per unit culture were studied with mature seeds from five indica rice genotypes as explants. Based on the morphology, the calli were classified into four types as I to IV. Type I and type II are most suited to initiate suspension cultures or as target material for transformation. Number of plants regenerated per unit culture, formation of easily dissociating cell clusters and frequency of type I and type II calli were highest on NBKNB medium. Thus NBKNB medium is suitable for in vitro culture of even the hitherto recalcitrant indica genotypes.

The salicylic acid-induced changes in the polypeptide patterns of barley (Hordeum vulgare L.) leaves have been analysed using two-dimensional gel electrophoresis. An optimized 2-D PAGE protocol was used and gave reproducible 2-D gels from leaf crude protein extracts with a high number of detected polypeptides. When applied for 24 h SA affected the expression of a number of soluble proteins. Most of them appeared to be down-regulated. Although no abundant expression of specific proteins was observed, we detected three polypeptides that were present only in SA-treated leaves.

Somatic embryogenesis in pigeonpea [Cajanus cajan (L.) Millsp.] has been achieved using cotyledon segments of mature seeds as explants. A large number of globular somatic embryos were induced directly from cotyledons of genotypes T-15-15, GAUT-82-90 and GAUT-82-99 when cultured on EC6 basal medium supplemented with 2.22, 4.44, 13.32 or 22.2 μM N⁶-benzylaminopurine (BAP) and 0.45, 1.36, 2.27, 4.54 and 13.62 μM thidiazuron. Somatic embryos developed into cotyledonary stage when the globular embryos were transferred to Murashige and Skoog's (MS) basal medium containing 2.89 - 14.43 μM gibberellic acid. Maturation of somatic embryos was achieved on half strength MS medium with 0.38 μM abscisic acid. The mature somatic embryos were germinated on MS medium supplemented with 0.44 μM BAP and the plantlets were hardened and transferred to soil.

Accelerated ageing of Dendrocalamus strictus Ness seeds at 42 ± 1°C and 100% relative humidity for 1 to 8 d was conducted. Seeds lost viability and changed their biochemical constituents. Reductions in the contents of sugars, starch, proteins and lipids were found. Decrease in the activity of the peroxidase as well as acid and alkaline phosphatase were also observed. Increase in total free amino acids content and the activity of amylase confirmed the degradation of seed reserves.

The influence of nitrogen deprivation on leaf development and the biomechanics of leaf growth were studied using maize (Zea mays L.) seedlings grown under low irradiance. Although the nitrogen deprivation had no significant effect on photosynthesis, the leaf length, the leaf area, and the total assimilation area of plants decreased. The mature size of the epidermal cells was not altered, while the cells of nitrogen-deprived plants reached their final length closer to the leaf base than the epidermal cells of control plants. Decreases in the length of the growing zone (from 50 to 30 mm) and in the maximum value of relative elemental growth rate (from 0.08 to 0.06 mm mm^-1 h^-1) were observed in the nitrogen deprived plants. The maximal value of growth velocity in the control treatment was higher along the elongation zone, except for the basal 20 mm, where there was no significant difference between the control and the N-deprived plants. The net deposition rates of water and dry matter were also affected by nitrogen deprivation: the values of these features decreased and the spatial position of the maximum of the deposition rates shifted towards the leaf base.

A set of 28 fibre flax and linseed cultivars differing in plant morphology and technological parameters were analysed by isozyme markers in five ontogenetic phases. Relatively high isozyme polymorphism was observed using polyacrylamide gel electrophoresis. Altogether 18 isozyme systems produced 145 different bands; 66 of them (45.52 %) have been found to be polymorphic. The highest level of polymorphism was found in acid phosphatase and esterase, polymorphism was detected in aconitase, diaphorase, glutamate dehydrogenase, peroxidase and superoxide dismutase as well. The highest number of unique isozymic spectra (cultivar × enzyme × ontogenetic phase) was detected in the phase of shoot with removed cotyledons. Electrophoretic analysis of all polymorphic isozymes enabled to distinguish 20 cultivars (71 %) in the screened cultivar set.

The seasonal dynamics in content and distribution of N-rich compounds between overwintering organs of Calamagrostis epigeios were examined. Samples were taken both from plants grown in natural conditions and in containers with controlled nutrient supply. There were significant changes in content of nitrate, free amino acids and soluble protein in all investigated plant parts during the course of a year. Amino acids showed both the highest maximum and seasonal fluctuation among the all N compounds observed and, therefore, appear to have a central role in N storage. Their content rises in the autumn, remains stable during winter and declines quickly at the beginning of spring. The most abundant amino acids in the end of winter storage period - asparagine, arginine and glutamine - constituted about 90 % of N in fraction of free amino acids. The portion of N stored in soluble proteins, however, was considerably smaller compare to both amino acids and nitrate. The amount of N stored in rhizomes of C. epigeios was smaller than in roots and stubble base before the onset of spring re-growth. This indicates that roots and stubble base are particularly important for winter N storage in this species.

Vigna radiata (L.) seedlings (5-d-old) were exposed to different concentrations of NaCl in light and in dark. The content of proline in the shoots increased with an increase in NaCl concentration, in light as well as in dark. But, irrespective of the concentration of NaCl, proline accumulation in the shoots was higher in light than in dark. Pretreatment of seedlings with dichlorophenyl dimethyl urea (DCMU) did not make any significant difference in light promoted stress induced proline accumulation. As DCMU is a potent inhibitor of photosynthetic electron transport, the light reaction of photosynthesis was not responsible for the observed light promotion of stress induced proline accumulation. In another set of experiments, 5-d-old green as well as etiolated seedlings were exposed to NaCl stress in the presence of different concentrations of sucrose. Irrespective of the concentration of sucrose used, proline content in shoots of stressed seedlings was higher in light than in dark. Although, sucrose enhanced NaCl stress induced increase in proline content in dark by about 32 %, this enhancement was not comparable to the 286 % increase in proline content brought about by light. These results showed that certain factors other than photosynthesis play a role in light promotion of stress induced proline accumulation.

An analysis of the effect of metabolic inhibitors, sugars, and fusicoccin on the trans-plant electrical potential difference arising across one-week-old green or herbicide-treated Chenopodium rubrum L. plants was performed. The substances were applied either to the solution bathing the root or in the form of drops to the stem. The respiratory inhibitors (KCN and salicylhydroxamic acid), sulfhydryl agents (N-ethylmaleimide and p-chloromercuribenzene sulfonic acid) and proton ionophore (carbonyl cyanide m-chlorophenylhydrazone) affected the electrical potential, the kinetics of the induced changes varying with different inhibitors and site of application. None of the applied sugars (sucrose, glucose or sorbitol), ATPase stimulator fusicoccin or inhibitor vanadate exerted any appreciable effect on the electrical potential. An effect of sucrose could be observed in the case of its application immediately following de-rooting, especially in the case of herbicide-treated plants. These results we explain by non-participation of the sucrose transporter or the proton ATPase in the generation of the electrical potential difference across intact plants (apoplast-apoplast configuration).

Diurnal and seasonal changes of net photosynthetic rate (P_n) and the efficiency of photosystem 2 (F_v/F_m) were measured on two perennial species growing on a soil catena in semi-arid south-east Spain. Stipa tenacissima, a tussock grass, grows on shallow soil at the top of the catena and Retama sphaerocarpa, a leguminous shrub, grows in the valley bottom. A linear relationship was found between light saturated photosynthetic rates (P_max) and diffusive leaf conductance (g_l) in both Retama and Stipa indicating that the intercellular CO₂ concentration (c_i) was maintained constant in both species diurnally. Relatively high values of calculated c_i in Retama cladodes suggested that was not the primary limitation to carbon assimilation. F_v/F_m for the two species when well watered was around 0.8. Although Retama cladodes maintained this value throughout the year, F_v/F_m decreased to a minimum of 0.43 in Stipa leaves, at the end of the dry season. Our data suggest that plants in the Rambla Honda can substantially reduce transpiration without reducing photosynthetic rates to the same extent by closing their stomata, because P_n is reduced primarily by high respiration, decreased mesophyll conductance and by photoinhibition or permanent damage of photosystem 2.

Cell suspension culture of Eschscholtzia californica Cham. were permeabilized by Tween 20 or 80, and immobilized by glutaraldehyde. The highest invertase activity was at pH 4.5 and temperature 50 °C. The hydrolysis of the substrate was linear for 5 h reaching 60 % conversion. The cells had high invertase activity and a good stability, and in long-term storage they showed convenient physico-mechanical properties.

Treatment of spruce, fir and oak trees with herbicides, which may be one of the forest damage inducing agents, caused pronounced changes in the contents and distribution of indole-3-acetic acid (IAA) and cytokinins (CKs) one year after treatment, i.e. at the time of the first microscopically visible damage in treated trees. In Picea pungens IAA content increased in the terminal buds by about 105 % and in the apical buds of the first order branches by 220 %. The same was true for young sprouts of Abies nordmanniana, while in leaves of oak trees IAA content was decreased by 15 % after glyphosate treatment and by 30 % after 2,4-dichlorophenoxyacetic acid (2,4-D) treatment. Another striking feature was a significantly decreased content of IAA in the lower parts of roots in Picea pungens (50 % of the control), which is accompanied by an increase in IAA content in the middle part of the roots (130 %). On the other hand, the IAA content of both sprouts and roots of A. nordmanniana was significantly increased after herbicide treatment.
In P. pungens, the content of free cytokinins (sum of zeatin, zeatin riboside, isopentenyladenine and isopentenyladenosine) decreased due to herbicide treatment. The strongest decrease was seen in roots, especially in their upper and middle parts (the average reduction of cytokinin content in roots was 63 %). In the above-ground organs the reduction was seen namely for isopentenyladenine and isopentenyladenosine, while the abundance of zeatin riboside was, on the other hand, higher in treated plants. In Quercus robur leaves, the total content of cytokinins also decreased, namely after glyphosate treatment. In consequence of these changes, CK/IAA ratio decreased pronouncedly in all organs of herbicide-treated trees, with the exception of oak leaves treated by 2,4-D.

Treatment of Taxus chinensis cell suspension cultures with fungal elicitor resulted in an oxidative stress characterized by H₂O₂ production, malondiadehyde (MDA) accumulation and cell death. This oxidative stress was dependent on the concentration of elicitor. Cells exposed to elicitor accumulated taxol, however, not proportional to elicitor concentration. High production of taxol occurred in cells treated with the suitable elicitor concentration. We concluded that oxidative stress had the deleterious effect on taxol production. Simultaneous treatment with elicitor and ascorbic acid (ASA) changed the oxidative stress and taxol production. Production of taxol in cells treated with 200 mg dm^-3 elicitor and ASA was enhanced compared with that in cells treated with only 200 mg dm^-3 elicitor, while production of taxol in cells treated with 100 and 50 mg dm^-3 elicitor and ASA was decreased compared with that in cells treated with 100 and 50 mg dm^-3 elicitor.

Ornithine carbamoyltransferase (OCT) from spinach (Spinacea oleracea L.) was purified to homogeneity and studied for some kinetic and structural properties. The enzyme showed a specific activity of 436 U mg^-1, its molecular mass was approximately 118 kDa as estimated by Sephacryl S-200 gel filtration chromatography, the purified protein ran as a single band of 38 kDa in sodium dodecyl sulfate-polyacryamide gel electrophoresis. The enzyme catalyses an ordered bi-bi-sequential reaction in which carbamoyl phosphate binds first, followed by L-ornithine; L-citrulline leaves first, followed by phosphate. The Michaelis constant was 0.19 mM for L-ornithine and 13.1 µM for carbamoyl phosphate; the dissociation constant for the enzyme and carbamoyl phosphate complex was of 19 µM. The K_m of the reaction decreases from pH 6.0 to pH 10.4. The enzyme is heat-labile, but it was protected from thermal inactivation by substrates; more by ornithine alone than by two substrates acting together.

This study investigated the influence of osmotic stress, induced by sorbitol and sucrose combinations, on growth and proline accumulation in callus cultures of rice (Oryza sativa L.). Dehusked mature seeds, cv. Hassawi, were induced to callus on MS medium supplemented with 4.52 µM 2,4-dichlorophenoxyacetic acid (2,4-D) and 2.32 µM 6-furfurylaminopurine (kinetin). The medium also contained 29.2, 58.4, 87.6, and 116.8 mM sucrose combined with 0, 54.9, 109.8, and 164.7 mM sorbitol. Callus formation was observed in about 35 % of the cultured seeds irrespective of the sugar treatment. An increase in callus mass was observed as sucrose concentration increased reaching a maximum growth at 87.6 mM. Callus growth was enhanced in response to 54.9 mM sorbitol but at higher concentration it was inhibitory. Best callus growth was obtained on a medium containing 54.9 mM sorbitol combined with 87.6 mM sucrose. Increasing osmotic stress, as a consequence of increasing sucrose and sorbitol concentrations, induced proline accumulation and the highest concentration of proline, 5.8 µmol g^-1(f.m.), was obtained on 164.7 mM sorbitol combined with 116.8 mM sucrose.

A reliable method for the long-term conservation of date palm tissue cultures is described. In vitro shoot bud and callus culture were successfully stored for 12 months at 5°C in the dark. At this conditions high percent of cultures remained viable without serious signs of senescence. However, the growth rate decreased as storage period increased. The role of sorbitol as osmotic agent in storage was examined. Health shoot bud cultures were obtained after 6 months of storage on medium containing 40 g dm^-3 sorbitol. This period extended for 9 months in case of callus cultures.

Four physiologically and phenotypically diversified tobacco (Nicotiana tabacum L. cv. Samsun) plantlet variants had been generated by cultivation on media either lacking or containing sucrose (0 and 3 %, m/v) under two different photon flux densities (PFD), 50 µmol m^-2 s^-1 (LL) and 200 µmol m^-2 s^-1 (HL). Plantlets were transferred into soil without any pre-acclimation and grown either under PFD of 200 µmol m^-2 s^-1 or 700 µmol m^-2 s^-1. Sucrose feeding in vitro resulted in reduced degree and duration of wilting after transfer. The highest readiness for ex vitro acclimation was found in 3 % HL plants, in which changes of photosynthetic apparatus and stress responses were the smallest. On the contrary, the steepest decline of Fv/Fm ratio on the first day after transplantation, doubled chlorophyll content and almost tripled D1/LHC 2 ratio after 7 d of ex vitro growth under 700 µmol m^-2 s^-1 characterized 0 % HL plants, which had suffered chronic photoinhibition in vitro. Remarkably high abscisic acid content at the end of in vitro cultivation and during acclimation as well as increased synthesis of both D1 and LHC 2 proteins even at the end of analyzed acclimation period were found only in 0 % LL plants. Increase of D1/LHC 2 ratio and chlorophyll contents demonstrate that in vitro developed leaves of all plant variants are able to acclimate to new environment. The most surprising result in the whole study is the drop of D1 protein synthesis in all plants on the 3^rd day. Five times decline of photoprotection level of xanthophylls in plants after ex vitro transfer into the same PFD showed stress character of in vitro cultures.

The effect of two elicitor types prepared from three different fungi on the alizarin content and the ultrastructure of Rubia tinctorum cells was studied. The de novo alizarin synthesis took place predominantly during the first day of treatment then it was followed by a constant release of alizarin into the medium. The alkalinization of the medium was similar in every treatment. The number of the living cells did not changed during 24-h elicitor treatments, but it decreased significantly after 96 h. The appearance of vacuolar bodies, and the change of the plasmalemmasome structure from vesiculo-reticular to reticulo-lamellar were the most typical morphological syndromes due to elicitation. Phytium elicitor proved to be the least effective, and Botrytis elicitor seemed to be the most effective.