Thirty-six F₂ hybrid poplar (Populus trichocarpa × P. deltoides) clones were fumigated with ozone to record its effects on growth, correlate them with stomatal response and screen for ozone sensitivity. Fumigation was applied for 6 to 9 h each day for approximately 3 months at ozone concentrations of 85 to 128 μg g^-1 using open-top chambers. Height, diameter, number of leaves, stomatal conductance, transpiration rate, total biomass, biomass components and root/shoot ratios were reduced by ozone stress. Percent of leaf fall in ozone-treated plants was nearly three times higher than in control plants exposed to charcoal-filtered air. Leaf senescence, because of ozone exposure, did not appear to be associated with reduced biomass production. Some clones had a high percentage of leaf-fall with ozone exposure, but were able to maintain total biomass production near that of the control. Their response may be an example of an ability to adjust or compensate for ozone damage. There was no significant or consistent relationship between stomatal conductance and total biomass or the change in stomatal conductance as a result of ozone exposure and the change in total biomass. Taken together, these results suggest that effects of ozone on poplar growth cannot be solely correlated to changes in stomatal conductance, more physiological and biochemical parameters should be examined.

Biomass growth and ginsenoside production in cell suspension and adventitious roots of Panax ginseng C.A. Meyer cultures cultivated both in Erlenmayer flasks and a 3 dm³ bioreactor were studied. The maximum content of ginsenosides was found in the suspension culture cultivated in the bioreactor (4.34 % dry mass), however the saponin content was limited to two major ginsenosides, Rb₁ and Rg₁. The production of ginsenosides in adventitious roots was lower (1.45 or 1.72 % dry mass), nevertheless, the full range of ginsenosides was detected.

Changes in the activities of sucrose synthase (SuSy), ADP-glucose pyrophosphorylase (AGPase), UDP-glucose pyrophosphorylase (UGPase), alkaline inorganic pyrophosphatase, 3-phosphoglycerate (3-PGA) phosphatase and amylases were monitored in relation to accumulation of starch in developing pods of mung bean (Vigna radiata L.). With the advancement in the seed development, the contents of starch rose with a concomitant fall in the branch of inflorescence and podwall after 10 d after flowering. The activity of UDPase in all the three pod tissues remained higher than the activity of AGPase showing it to be an important enzyme controlling carbon flux. The activity of alkaline inorganic pyrophosphatase in developing seed in contrast to 3-PGA phosphatase correlated with starch accumulation rate. Activity of β-amylase increased in all the pod tissues till maturity. It appears that the cooperative action of SuSy, UGPase and AGPase controls the efficient partitioning of sucrose into ADP glucose and thereby regulate the seed sink strength of the mung bean.

This study assessed the effects of salinity and drought upon leaf construction (CC) and maintenance (MC) costs in Avicennia germinans growing under contrasting soil salinities in the field. Additionally, an analysis of leaf chemical composition was carried out to determine the underlying reasons for possible variation in CC. With the increase of external salinity, leaf osmotic potential (ψ_s) declined and a significant negative correlation was found between both variables. Changes in average CC were about 15 % when ψ_s changed by 85 %. Despite this, leaf ash-free heat of combustion per unit of leaf dry mass remained relatively constant at 21.3 ± 0.9 kJ g^-1 in all conditions. The estimated maximum and minimum CC for the synthesis of protein present in leaves increased significantly with total leaf CC. Conversely, the estimated CC for lipid synthesis shows a tendency to decrease with total leaf CC. Under conditions of high salinity, ash content increased by 78 % compared to that of leaves collected at low salinity. It is concluded that undergoing changes in proteins and lipids (expensive) and ash (cheap) explain the changes in CC under contrasting salinities. Additionally, the average MC remained almost constant at moderate salinity and declined by 6 % under hyper-saline conditions. Thus, differences in CC and MC with salinity are explained in part by changes in the chemical composition of different compound fractions.

An efficient system for shoot regeneration and Agrobacterium-mediated gene transfer into Brassica napus was developed through the modification of the culture conditions. Different concentrations of benzyladenine (1.5, 3.0 and 4.5 mg dm^-3) and thidiazuron (0.0, 0.15 and 0.30 mg dm^-3) were evaluated for shoot regeneration of 7, 14 and 21-d-old hypocotyl explants. Maximum shoot regeneration frequency was obtained in 21-d-old explants using 4.5 mg dm^-3 benzyladenine and 0.3 mg dm^-3 thidiazuron. Under above culture condition, the highest percentage of shoot regeneration frequency was 200 %. Agrobacterium-infected explants grown on the selection medium gave rise to transgenic shoots at a frequency of 11.8 %. Transformed shoots rooted when cultured on a medium supplemented with 2 mg dm^-3 of indolebutyric acid and 10 mg dm^-3 kanamycin. The rooted plantlets were successfully established in the soil and developed fertile flowers and viable seeds. Evidences for transformation were confirmed by GUS assay and PCR analysis.

Acacia ampliceps Maslin and Eucalyptus camaldulensis Dehnh. were grown for one year in lysimeters at three soil moisture regimes: 100 % (well-watered), 75 % (medium-watered) and 50 % (low-watered) of total plant available water. Biomass yield of both species increased with increase in soil moisture. Water-use efficiency (WUE) of E. camaldulensis decreased and that of A. ampliceps increased markedly with decrease in available soil moisture. A. ampliceps showed 4 - 5 times more biomass yield than E. camaldulensis grown at similar soil moisture. A. ampliceps showed almost 5, 9 and 12 times higher WUE than E. camaldulensis under low-, medium- and well-watered treatments, respectively. Significant negative correlation of δ¹³C with WUE (r = -0.99) was observed in A. ampliceps. In contrast, δ¹³C of E. camaldulensis showed a significant positive correlation with WUE (r = 0.82).

The somatic embryogenesis potential of zygotic embryo axes of peanut (Arachis hypogaea L. cv. DRG-12) at different stages of development was evaluated by culturing on MS medium with 18.1 μM 2,4-dichlorophenoxyacetic acid (2,4-D). A 100 % frequency with 18.3 somatic embryos per explant was observed from 4 mm long immature zygotic embryo axes collected 31 - 40 d after pollination. Medium supplemented with 16.6 μM picloram resulted in slow development of somatic embryos whereas in the presence of 21.5 μM α-naphthaleneacetic acid (NAA), the explants underwent maturation with induction of roots after 30 d. The changes in protein profiles in zygotic embryo axes at different stages of development correlated with their potential to form somatic embryos. Immature zygotic embryo axes exhibited high frequency somatic embryogenesis in the stage preceding abundant accumulation of 22 and 65 kDa proteins. The content of 22 and 65 kDa proteins decreased immediately after culture on medium fortified with 18.1 μM 2,4-D and increased again after 12 d of culture coinciding with the development of somatic embryos on the explants. The content of 22 and 65 kDa proteins was low at 15 d of culture on medium supplemented with 16.6 μM picloram possibly due to slow development of the somatic embryos on the explant. On maturation medium containing 21.5 μM NAA, a marked increase in the content of 22 and 65 kDa proteins in 15 d-old cultures was observed.

1, 5, or 10 mM arginine and 25, 50, or 100 μM cysteine were added in the Murashige and Skoog medium. By increasing arginine concentration the number of shoots per explant increased. Inclusion of 50 μM cysteine in the medium resulted in maximum number of shoots but it was not significantly different in comparison to 10 mM arginine. The chlorophyll content was significantly increased in explants treated with 10 mM arginine in comparison to the control, 1 mM arginine and 25 μM cysteine. By increasing arginine and cysteine concentrations of the medium, N, K, and Ca contents of explants increased but no significant changes in P, Mg, Fe, Mn, Zn, and B contents were observed.

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.

Explants obtained from in vitro-propagated plantlets of two potato cultivars, Shepody and Atlantic, were treated with five doses of γ-radiation (0, 2, 4, 6 and 8 Gy) to investigate the stimulating effects of low irradiation on the production and quality of microtubers in vitro. Microtubers of both cultivars treated with γ-radiation initiated 5 d earlier than in the non-irradiated control. The whole period of microtuberization was prolonged by 10 - 15 d with 4, 6 and 8 Gy irradiation treatment for cv. Atlantic. Irradiation of the plantlets (4 Gy) led to a significant increase not only in the microtuber number (116.7 and 34.5 % over the control) but also in the fresh mass (77.6 and 23.2 % in Shepody and Atlantic, respectively). Low dose irradiation (2 - 4 Gy) increased the starch content of microtubers. High doses (6 - 8 Gy) enhanced ascorbic acid and reducing sugar contents. 4 - 6 Gy doses also effectively increased the protein contents of microtubers.

There is increasing evidence that the sucrose normally added to the culture medium affects negatively the photosynthetic capacity of plantlets. At the same time, however, sucrose cannot be eliminated from the medium, as it is required for normal in vitro growth. We argue that this is true only under the conventional light conditions of growth-rooms. In the present paper irradiance of growth-rooms was increased 10 times and although the sucrose-inhibitory effect was found at high sucrose concentrations, it was possible to grow coconut (Cocos nucifera L.) plantlets without sucrose. Those plantlets showed both high photosynthetic capacity and comparable in vitro growth to those grown with sucrose in the medium under conventional growth-room irradiance. Nevertheless, the best growth was achieved under mixotrophic conditions where at high irradiance and moderate sucrose concentrations plantlets accumulated 27 % more biomass than plantlets grown without sucrose under high irradiance and 43 and 73 % more biomass than their counterparts at low irradiance with or without sucrose, respectively.

The responses of antioxidative system of rice to chilling were investigated in a tolerant cultivar, Xiangnuo-1, and a susceptible cultivar, IR-50. The electrolyte leakage and malondialdehyde content of Xiangnuo-1 were little affected by chilling treatment but those of IR-50 increased. Activities of suoperoxide dismutase, catalase, ascorbate peroxidase and glutathione reductase, and ascorbic acid content of Xiangnuo-1 were remained high, while those of IR-50 decreased under chilling. The results indicated that higher activities of defense enzymes and higher content of antioxidant under stress were associated with tolerance to chilling.

The physiological responses to NaCl salinity were investigated in two floating aquatic macrophytes, Pistia stratiotes L. and Salvinia molesta L. With the increasing NaCl concentration a decrease in chlorophyll and carotenoid contents was recorded in Salvinia as compared to Pistia. Also a greater increase in H₂O₂ accumulation and lipid peroxidation was observed in the shoot and root tissues of Salvinia as compared to Pistia. The superoxide dismutase, glutathione reductase, catalase and guaiacol peroxidase activities, and ascorbate and glutathione contents increased in Salvinia and Pistia shoot and root tissues in response to NaCl.

Exposure of barley plants (Hordeum vulgare L.) to soil flooding for 2 to 24 h reduced the net photosynthetic rate and transpiration rate. Stomatal conductance also decreased in flooded plants. Stomatal closure started within 2 - 6 h and stomata remained closed up to 24 h of treatment.

A rapid plantlet regeneration system for Perilla frutescens was established from cotyledon and hypocotyl explants. A maximum of 91.06 % cotyledon and 76.4 % hypocotyl explants could directly produce shoots (3.09 ± 0.18 shoots per explants) on Murashige and Skoog (MS) medium. The optimum hormone combinations were 4.44 μM 6-benzylaminopurine (BA) for cotyledon and 2.22 μM BA + 2.85 μM indole-3-acetic acid (IAA) for hypocotyls. Rooting was induced on half-strength hormone-free MS medium. After transplantation to soil, approximate 80 % of the regenerated plantlets could survive, flower and fruit. Moreover, some morphological abnormalities were found among the regenerated plants.

Stable transformation of Coffea canephora P. was obtained by particle bombardment of embryogenic tissue. Leaf explants were cultured on medium supplemented with 5 µM isopentenyl-adenosine to induce direct embryogenesis. Explants with somatic embryos were transferred to half strength MS medium with 9 µM 2,4 dichlorophenoxyacetic acid. After 2 weeks, the explants with somatic embryos and embryogenic tissue were bombarded with tungsten particles (M-25) carrying the plasmid pCambia3301 (containing the bar and uidA genes) using a high pressure helium microprojectile device. The bombarded explants were submitted to selection on medium containing 5 µM ammonium glufosinate herbicide as selective agent. After 6 months, putative transgenic embryos were transferred to a growth regulator-free medium for germination. The regenerated plantlets were β-glucuronidase (GUS) positive whereas no GUS activity was observed in non-transgenic controls. Incorporation of the bar gene into the genome was confirmed by PCR and Southern blot analysis of the regenerated transformed plants. Greenhouse grown transgenic coffee plants were found to withstand the recommended level of the herbicide Finale™ for weed control.

Ethylene concentration in the culture tubes of peach rootstock regenerants of three genotypes (Cadaman, GF-677, Myrobalan 29C) was increased by the inclusion of 20 µM salicylic acid (SA), methionine (METH) and ethephon (ETH) in the MS medium whereas it was decreased in regenerants exposed up to 20 µM AgNO₃. In leaves of the regenerants the increase of ethylene concentration was accompanied with an increase of non-enzymatic antioxidant activity while remarkable genotype-depended changes in the activities of catalase, peroxidase and their isoenzymes were recorded suggesting that ethylene accumulation imposes oxidative stress responses. However, the results showed that some differences could be observed in the activity of isoenzymes in regenerants exposed to SA in respect to METH and ETH-treated ones.

The cladistic analysis of the DNA sequences of the internal transcribed spacers of ribosomal cistrons (ITS1 and ITS2) for 20 species of Cicer L. (among which all the annuals), shows that various sections of the genus are not monophyletic. Annual species do not form a clade: C. arietinum, in fact, is closely related to both C. echinospermum and C. reticulatum, whereas C. bijugum, C. judaicum, and C. pinnatifidum form a separate clade. The annual C. cuneatum is sister group to the perennial C. canariense and both are archaic species within the genus. C. yamashitae is, on the contrary, the only annual species belonging to a group of perennials, within which close relationships are evident between C. graecum and C. montbretii as well as among a group of mainly Asian species.

Several polypeptides were induced in leaves of Sesbania sesban var. bicolor under water stress (desiccation). Among them, the SDS-PAGE resolved a few high molecular mass polypeptides along with one major of 66 kDa. After boiling the total protein fraction, some low molecular mass polypeptides (10 - 30 kDa) as well as the one of 66 kDa remained stable. The latter (66 kDa) polypeptide is also regulated by exogenous application of ABA, indicating its significant role in adaptation of sesban to drought.

Common polypody (Polypodium vulgare L.) belongs to desiccation-tolerant ferns. The structure of storage parenchyma of their rhizome was examined by transmission electron microscopy after dehydration and subsequent rewetting. Analysis revealed that treatment with supplemental abscisic acid resulted in protection of cells against ultrastructural damage compared to untreated ones. Dehydration rate appears to modify the ability of rhizome parenchyma to stand water stress.

The effects of five different N-sources (KNO₃ + NH₄NO₃ = control, KNO₃, NH₄NO₃, NH₄H₂PO₄, L-alanine) on growth, nutritional status, chlorophyll (Chl) content, and photosynthetic parameters of the apple rootstock MM 106 shoots cultured in vitro were investigated. In comparison to all the other treatments, control explants grown on a MS medium containing KNO₃ + NH₄NO₃ had the highest fresh mass, Chl content, net photosynthetic rate, transpiration rate, and stomatal conductance.

The effect of AlCl₃ on endosperm reserve mobilization of rice grains or dehulled rice grains during germination was investigated. AlCl₃ had no effect on grain fresh and dry masses, protein and starch contents, and α-amylase and protease activities in endosperm of germinating rice grains. However, when dehulled rice grains were treated with AlCl₃, AlCl₃ inhibited the decrease in fresh mass, dry mass, and starch and protein contents, and the increase in α-amylase and protease activities in endosperm. Evidence is provided to show that the hull is a barrier against influx of Al to endosperm.

The effects of nitrogen [75 and 150 kg (N) ha^-1] and elevated CO₂ on growth, photosynthetic rate, contents of soluble leaf proteins and activities of ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) and nitrate reductase (NR) were studied on wheat (Triticum aestivum L. cv. HD-2285) grown in open top chambers under either ambient (AC) or elevated (EC) CO₂ concentration (350 ± 50, 600 ± 50 μmol mol^-1) and analyzed at 40, 60 and 90 d after sowing. Plants grown under EC showed greater photosynthetic rate and were taller and attained greater leaf area along with higher total plant dry mass at all growth stages than those grown under AC. Total soluble and Rubisco protein contents decreased under EC but the activation of Rubisco was higher at EC with higher N supply. Nitrogen increased the NR activity whereas EC reduced it. Thus, EC causes increased growth and P_N ability per unit uptake of N in wheat plants, even if N is limiting.

The effects of different cadmium concentrations [17 mg(Cd) kg^-1(soil) and 72 mg(Cd) kg^{- 1}(soil)] on Cannabis sativa L. growth and photosynthesis were examined. Hemp roots showed a high tolerance to Cd, i.e. more than 800 mg(Cd) kg^-1(d.m.) in roots had no major effect on hemp growth, whereas in leaves and stems concentrations of 50 - 100 mg(Cd) kg^-1(d.m.) had a strong effect on plant viability and vitality. For control of heavy metal uptake and xylem loading in hemp roots, the soil pH plays a central role. Photosynthetic performance and regulation of light energy consumption were analysed using chlorophyll fluorescence analysis. Seasonal changes in photosynthetic performance were visible in control plants and plants growing on soil with 17 mg(Cd) kg^-1(soil). Energy distribution in photosystem 2 is regulated in low and high energy phases that allow optimal use of light and protect photosystem 2 from overexcitation, respectively. Photosynthesis and energy dissipation were negatively influenced by 72 mg(Cd) kg^-1(soil). Cd had detrimental effects on chlorophyll synthesis, water splitting apparatus, reaction centre, antenna and energy distribution of PS 2. Under moderate cadmium concentrations, i.e. 17 mg(Cd) kg^-1(soil), hemp could preserve growth as well as the photosynthesis apparatus, and long-term acclimation to chronically Cd stress occurred.

Inhibitory effects of flavonoids on plant alternative respiration were investigated using isolated mitochondria of Vigna radiata seedlings. The antioxidant flavonoids quercetin and myricetin effectively inhibited alternative respiration. We suggest that radical scavenging activity is involved in the inhibitory mechanism.