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Nanomaterials (NMs) have received global attention because of their unique physicochemical properties. Recent advances in nanotechnologies have proved useful in improving plant growth and yield, quality of food materials, and efficacy of phytomedicine. Nanoparticles (NPs) of several metals and metal oxides are now being synthesized by using plant extracts or their products as the reducing and capping agents. Many NPs are used as nutrient carriers for plants and have shown positive impact on the overall plant performance. However, their reported toxicity in biological/physiological environment is a point of concern. This chapter provides an overview of the current and the expected future status of NM-plant interaction.

Introduction Do non-employed people with disabilities want to work, and if so, what types of jobs do they want? Researchers seeking to explain the low employment rate among people with disabilities have focused primarily on skill gaps, employment disincentives from disability income, accommodation mandates, and (to a lesser extent) employer attitudes and unwelcoming corporate cultures. There has been little attention paid to the attitudes of non-employed people with disabilities. Methods This paper uses the 2006 General Social Survey, a representative national survey of US adults that has disability information and a special supplement on worker preferences, to examine the above question. Results We find that, relative to their non-disabled counterparts, non-employed people with disabilities are (a) as likely to want a job but less likely to be actively searching, (b) as likely to have prior job experience, and (c) similar in their views of the importance of income, job security, and other valued job characteristics. The results, which vary little by type of impairment, indicate that the low employment rate of people with disabilities is not due to their reluctance to work or different job preferences. Conclusion Combined with evidence that a large share of new jobs can be performed by people with disabilities, the findings point toward the value of dismantling barriers to employment facing many people with disabilities.

In this study a series of new 1-(2-aryl-5-phenethyl-1,3,4-oxadiazol-3(2H)-yl)ethanones 2a-e was synthesized by the cyclization of imines 1a-e using acetic anhydride. The products were evaluated for anti-bacterial and anti-fungal activity. Among the newly synthesized compounds, 1-(2-(4-(dimethylamino)phenyl)-5-phenethyl-1,3,4-oxadiazol-3(2H)-yl)ethanone (2a) and 1-(2-(4-chlorophenyl)-5-phenethyl-1,3,4-oxadiazol-3(2H)-yl)ethanone (2b) were found to possess maximum activity against the tested strains of S. aureus and P. aeruginosa. It was concluded that para-substitution enhances the activity of synthesized oxadiazoles.

Indian ginseng ( Withania somnifera L. Dunal), a medicinally important plant exposed to different concentrations of CuSO 4 (0, 10, 25, 50, 100 and 200 μM) for 30 d in vitro accumulated high amount of Cu in a concentration manner. Toxic effects of Cu on plants were reflected by the reductions in fresh weight (FW), shoot and root length, chlorophyll and carotenoids contents. Malondialdehyde (MDA), a decomposition product of polyunsaturated fatty acids hydroperoxides, often considered as a suitable biomarker for lipid peroxidation was induced in metal-treated plants compared to the control. This hypothesis is also confirmed by the higher lipoxygenase (LOX) activity, coupled with higher hydrogen peroxide (H 2 O 2 ) and superoxide anions (O 2 − ) content in treated plants. Ascorbate peroxidase (APX), monodehydroascorbate reductase (MDHAR), dehydroascorbate reductase (DHAR), glutathione- S -transferase (GST) and guaiacol-peroxidase (G-POD) activities of leaves were increased in the presence of Cu when compared to control plants indicated that antioxidant enzymes played an important role in protecting the plant from Cu toxicity. After native polyacrylamide gel electrophoresis (PAGE) analysis, six APX and four G-POD isoforms were detected and significantly induced in metal-treated plants as compared to control plants. The marked decrease in superoxide dismutase (SOD), catalase (CAT), glutathione reductase (GR) and glutathione peroxidase (GPx) activities seems to reflect its inability for eliminating the reactive oxygen species (ROS) resulting from Cu-induced oxidative stress. On the other hand, total phenolic contents increased with increasing concentration of Cu compared to the control. This study reveals that plants have the ability to grow in Cu polluted areas by altering various physiological changes. Since the level of total phenolic content in metal-treated plants increases, therefore, it is advisable to assess the biological activity of the plants before using for medicinal purposes.

The aim of this study was to investigate the effect of CO2 at various concentrations (1, 2.5 and 5%) on antioxidant enzymes and ginsenoside accumulation in Panax ginseng roots in 5 l airlift bioreactors (working volume 4 l). One and 2.5% CO2 was beneficial for root biomass accumulation, but 5% CO2 decreased the biomass. Ginsenoside concentration decreased with increasing concentration of CO2. No significant difference was observed in the malondialdehyde (MDA) content and lipoxygenase (LOX) activity between respective controls and CO2 treated roots. Antioxidant enzymes such as ascorbate peroxidase (APX), monodehydroascorbate reductase (MDHAR), glutathione reductase (GR), catalase (CAT), guaiacol peroxidase (G-POD) including reduced ascorbate and total glutathione were induced in CO2 exposed roots which emphasized the protective role of antioxidants against CO2 induced stress. Superoxide dismutase activity (SOD) which was induced after 15 days was significantly inhibited after 45 days. Glutathione-S-transferase (GST) and glutathione peroxidase (GPX) activities also increased when the roots were subjected to 1 and 2.5% CO2 compared to the respective controls but not at 5%. A higher reduced ascorbate to oxidized (ASC/DHA) ratio in CO2 treated root indicates the plant's ability to tolerate CO2 stress. These observations suggest that an increase in antioxidant enzymes may affect a defense response to the cellular damage induced by CO2. Probably, this increase could not stop the deleterious effects of CO2 concentration on ginsenoside concentration, but reduced stress severity and thereby allowing root growth to occur.

Compared to non-embryogenic callus, proembryonic mass, globular, and heart-shaped embryos of Eleutherococcus senticosus had higher levels of endogenous reduced glutathione (GSH). GSH content declined during the course of the embryo development (torpedo and cotyledon). Similarly, glutathione reductase that is involved in the recycling of GSH providing a constant intracellular level of GSH was also higher in globular and heart-shaped embryos. The transient increase in GSH contents also correlated with the changes in measured γ-glutamylcysteine synthetase activity over the same period. The endogenous levels of oxidized glutathione showed similar trend during development of the somatic embryos, whereas it declined in maturing somatic embryos. A pronounced increase in glutathione-S-transferase, glutathione peroxidase, catalase, and guaiacol peroxidase activity was observed during somatic embryo maturation. Ascorbate-glutathione cycle enzymes (ascorbate peroxidase; dehydroascorbate reductase and monodehydroascorbate reductase) activities also induced indicated that antioxidant enzymes played an important role during embryo development. These results suggested that the coordinated up-regulations of the antioxidant enzymes and glutathione redox system provide protection during somatic embryo development in E. senticosus. Antioxidant responses through alterations of the glutathione redox systems, have been described in the present studies have a significant role in somatic embryo development.

The aim of this study was to examine the possible antioxidant capacities of tissue cultured mountain ginseng (TCMG) root extract in acclimatised and potted plants of Spathiphyllum cannifolium , stressed by the application of polyethylene glycol (PEG). Plants were treated with 0% PEG (control), 10% PEG and 10% PEG plus with TCMG (63.5 mg/kg day) for a period of 10 and 20 days. The TCMG root extract was supplemented (63.5 mg/kg everyday) and the levels of thiobarbituric acid reactive substances (TBARS), hydrogen peroxide (H 2 O 2 ) and antioxidant enzymes were estimated in PEG induced S. cannifolium . PEG treated plants showed an induced accumulation of TBARS resulting in an inhibition of CAT, GR, GPx and GST activity indicating a clear oxidative stress. A significant increase in the activities of SOD, APX, G-POD, GPx, was observed in the leaves supplemented with TCMG root extract in PEG induced S. cannifolium indicating the ability of TCMG root extracts to ameliorate stress conditions. PEG treated plants reduced photosynthetic efficiency ( F v / F m ), indicating a down-regulation of photosynthesis of plant. Net CO 2 uptake ( A ), stomatal conductance ( g ), transpiration rate ( E ), relative water content (RWC) and leaf osmotic potential (LOP) were also reduced in PEG-treated plant. However, these parameters were well protected in plants treated with PEG plus TCMG root extract treated plant. These results confirm the effectiveness of TCMG root extract supplementation in detoxifying oxidative damage, which is produced excessively in PEG-induced S. cannifolium . Therefore, roots of Panax ginseng are considered as a good source of antioxidant and can be produced on a large scale and, probably useful for human health.

A large number of micropropagated Euphorbia millii shoots from temporary immersion bioreactor showed thick broad leaves that were translucent, wrinkled and/or curled and brittle, symptoms of hyperhydricity. The environment inside bioreactor normally used in plant micropropagation is characterised by high relative humidity, poor gaseous exchange between the internal atmosphere of the bioreactor and its surrounding environment, and the accumulation of ethylene, conditions that may induce physiological disorders. A comparison of hyperhydric shoots (HS) with normal plants shows marked increase in malondialdehyde (MDA) content in HS plants. MDA, a decomposition product of polyunsaturated fatty acids hydroperoxides, has been utilized very often as a suitable biomarker for lipid peroxidation, which is an effect of oxidative damage. This hypothesis is also confirmed by the higher lipoxygenase (LOX) activity in HS plants. The potential role of antioxidant enzymes in protecting hyperhydric shoots from oxidative injury was examined by analyzing enzyme activities and isozyme profiles of hyperhydric and non-hyperhydric leaves of E. millii. Superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) activity were significantly higher in hyperhydric tissue as compared to non-hyperhydric normal leaf tissue. After native polyacrylamide gel electrophoresis (PAGE) analysis, seven SOD isoenzymes were detected and the increase in SOD activity observed in hyperhydric tissue seemed to be mainly due to Mn-SOD and Cu/Zn-SOD. The activity of ascorbate peroxidase (APX), glutathione reductase (GR), monodehydroascorbate reductase (MDHAR) and dehydroascorbate reductase (DHAR) was proportionally increased in HS tissue compared to normal leaves indicating a crucial role in eliminating toxic H2O2 from plant cells. The depletion of GSH and total glutathione in spite of higher GR activities observed in HS tissue indicates that mechanism of antioxidant defense was by enhanced oxidation of GSH to GSSG by DHAR yielding ascorbate (AA). The antioxidant metabolism has been shown to be important in determining the ability of plants to survive in hyperhydric stress and the up regulation of these enzymes would help to reduce the build up of ROS.

Effects of three levels of photosynthetic photon flux (PPF: 60, 160 and 300 µmol m−2s−1) were investigated in one-month-old Phalaenopsis plantlets acclimatised ex vitro. Optimal growth, chlorophyll and carotenoid concentations, and a high carotenoid:chlorophyll a ratio were obtained at 160 µmol m−2s−1, while net CO2 assimilation (A), stomatal conductance (g), transpiration rate (E) and leaf temperature peaked at 300 µmol m−2s−1, indicating the ability of the plants to grow ex vitro. Adverse effects of the highest PPF were reflected in loss of chlorophyll, biomass, non-protein thiol and cysteine, but increased proline. After acclimatisation, glucose-6-phosphate dehydrogenase, shikimate dehydrogenase, phenylalanine ammonia-lyase (PAL) and cinnamyl alcohol dehydrogenase (CAD) increased, as did lignin. Peroxidases (POD), which play an important role in lignin synthesis, were induced in acclimatised plants. Polyphenol oxidase (PPO) and β-glucosidase (β-GS) activities increased to a maximum in acclimatised plants at 300 µmol m−2s−1. A positive correlation between PAL, CAD activity and lignin concentration was observed, especially at 160 and 300 µmol m−2s−1. The study concludes that enhancement of lignin biosynthesis probably not only adds rigidity to plant cell walls but also induces defence against radiation stress. A PPF of 160 µmol m−2s−1was suitable for acclimatisation when plants were transferred from in vitro conditions.

The effects of CO 2 levels (0.03, 0.5, 1, 2 and 5%) on growth and antioxidant responses in 5 l bioreactor (working volume 4 l) root suspension cultures of Echinacea angustifolia were studied. CO 2 caused reduction in growth, malondialdehyde content (MDA), lipoxygenase (LOX, EC 1.13.11.13) activity and superoxide anion (O 2 − ) accumulation along with high total phenols accumulation and pH levels. Maximal increases (37%) in total phenols were obtained at 1% CO 2 compared to the control. An increase in total glutathione and total ascorbate (ASC + DHA), accompanied with enhanced ascorbate–glutathione cycle enzymes were observed in CO 2 -treated roots, which played an important role for the detoxification of harmful substances. CO 2 also induced an increase in glutathione peroxidase (GPx, EC 1.11.1.9) and glutathione- S -transferase (GST, EC 2.5.18) activities. After native polyacrylamide gel electrophoresis (PAGE) analysis, three superoxide dismutase (SOD, EC 1.15.1.1) isoenzymes were detected. Increase in SOD and CAT (EC 1.11.16) activities observed at 0.5% CO 2 -treated roots and induced SOD activity seemed to be mainly due to Mn-SOD. However, both SOD and CAT activities were inhibited at 2 and 5% CO 2 but reached similar to control value. Three APX (EC 1.11.1.11) and three guaiacol peroxidase (G-POD, EC 1.11.1.7) isoenzymes were strongly detected, an increase in APX and G-POD activities suggests increased scavenging of ROS, indicating the tolerance to CO 2 . These results indicated that limited oxidative damage as shown by lower MDA level, low LOX activity and low O 2 − accumulation may be due to the induced activities of antioxidant enzymes and non-enzymatic antioxidant. It is therefore, suggested that roots cultured in a bioreactor could protect themselves from CO 2 by altering the defense systems.

In this study of tissue cultured Panax ginseng roots in bioreactor, growth responses, carbonyl content, phenolics, flavonoids, diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging activity, cysteine, non-protein thiol (NPSH) content, phenolics related enzymes and lignin content were analysed after exposure to copper (Cu 2+ ) sulfate at various concentrations. Cu 2+ significantly inhibited root growth and resulted in an increase in protein oxidation (21%) (measured as carbonyl content) at 50 μM. Cu 2+ stress resulted in increased activities of glucose 6 phosphate dehydrogenase (G6PDH), shikimate dehydrogenase (SKDH), phenylalanine ammonia lyase (PAL) and cinnamyl alcohol dehydrogenase (CAD). The ensuing effect was an accumulation of phenolics and lignin. The phenolics, flavonoids, cysteine and NPSH contents as well as the DPPH activity, increased by 26%, 83%, 30%, 40% and 76%, respectively, at 50 μM Cu 2+ treatment compared to the control after 40 days. The induced activities of substrate specific peroxidases (caffeic acid peroxidase, CA-POD), chlorogenic acid peroxidase (CH-POD), polyphenol oxidase (PPO) and β-glucosidase (β-GS) indicated that these enzymes played an important role in the synthesis of phenolics compounds. The results also provided evidence that the application of Cu 2+ at 25 and 50 μM was accompanied by a substantial increase in oxidative stress as indicated by protein oxidation and reduced root growth. The increase in phenolic compounds, related enzymes and lignin clearly reflects the protective response to cellular damage induced by higher levels of Cu 2+ .

Somatic embryos of Eleutherococcus senticosus were exposed at 12, 16, 24 and 30 °C for duration of 45 days in bioreactor. The effects of such treatments on the growth, eleutheroside B, E, E1, total phenolics, flavonoids, chlorogenic acid concentrations and antioxidant enzymes activities were investigated. The results revealed that low (12 and 18 °C) and high (30 °C) temperature caused significant decrease in fresh weight (FW), dry weight (DW), total phenolics, flavonoids and total eleutheroside accumulation, while low temperature increased eleutheroside E accumulation in somatic embryos. Low temperature significantly increased superoxide dismutase (SOD), catalase (CAT), dehydroascorbate reductase (DHAR) and glutathione reductase (GR) activities whereas a strong increase in ascorbate peroxidase (APX) and monodehydroascorbate reductase (MDHAR) activity was obtained at 12 °C grown somatic embryos. In contrast, high temperature significantly decreased antioxidant enzymes activities and even guaiacol peroxidase (G-POD) activity also decreased at low temperature in comparison to 24 °C grown embryos. These data suggest that low and high temperature treatment provoked an oxidative stress in E. senticosus embryos, as shown by the increase in lipid peroxidation. The increase in lipid peroxidation was paralleled by a rise in lipoxygenase (LOX) activity and hydrogen peroxide (H2O2) content. However, this stress was more prominent at high temperature than low temperature grown embryos. This result suggests that the reduced growth of embryo at 30 °C was concomitant with reduced efficiency of these protective enzymes. On the other hand, increases in antioxidant activities at 12 and 18 °C could also be a response to the cellular damage; however, this increase could not stop the deleterious effects of low temperature, but reduced stress severity thus allowing embryo growth to occur.

The effect of initial sucrose concentration was investigated in embryogenic cell cultures of Eleutherococcus sessiliflorus in bioreactors for production of eleutherosides, phenol, flavonoids and polysaccharide. The final dry cell weight was increased from 6.16 to 23.33 g l −1 with an increase of initial sucrose concentration from 10 to 70 g l −1 , but an even higher sucrose concentration of 90 g l −1 seemed to repress the cell growth. Furthermore, it was found that a high sugar level was favorable to the synthesis of eleutherosides, phenol and flavonoids, which may be due to higher osmotic pressure. A marked increase in malondialdehyde (MDA) content in germinating embryos was observed in high sucrose treatment. MDA, a decomposition product of polyunsaturated fatty acids hydroperoxides, has been utilized very often as a suitable biomarker for lipid peroxidation, which is an effect of osmotic stress. This hypothesis is also confirmed by the higher lipoxygenase (LOX) activity under this treatment. The much higher antioxidant enzyme activities in the culture fed with higher initial sucrose suggest that osmotic stress arising from a sudden increase in medium osmotic pressure. A hypothesis of osmotic stress and eleutheroside accumulation was confirmed from these results.

The effect of relative humidity (RH) and temperature on CO2 assimilation (An), stomatal conductance (Sc), transpiration rate (Tr), chlorophyll content, fresh and dry weight, leaf length, leaf area, leaf width, formation of new root and survival rate have been assayed in Doritaenopsis in growth chamber after 1 month of acclimatization. Reduced growth was observed at below and above 25 ◦ C whereas it was increased with increasing humidity. Relative water content (RWC) was decreased at 50% and 70% humidity after second day of transfer and recovered completely with the progression of acclimatization. RWC also reduced at high temperature but recovered slowly and a gradual decrease of RWC was observed at 15 ◦ C. A visual symptom of severe leaf tip burn was observed at 50–70% humidity and at 35 ◦ C during acclimatization. At 15 ◦ C and 50% humidity sudden decrease of photosynthetic efficiency ( Fv/Fm) was observed, which could not recover in temperature treated plantlets during acclimatization period. Chlorophyll content increased with increasing humidity and at 15 and 35 ◦ C chlorophyll content was decreased compared to 25 ◦ C. Chlorophyll a/b ratio was unchanged while total chlorophyll/carotenoids ratio was increased from low to high temperature. Exposure of plantlets to high temperature led to a noticeable decrease in An, Sc and Tr, and at 15 ◦ C they were more decreased whereas significant differences were not observed in the parameters tested under humidity after 25 days of acclimatization. During daytime at 15 ◦ C, increase in An, Sc and Tr indicates the plantlets adaptability in the new environment.

Roots of mountain ginseng (Panax ginseng) were exposed to various levels of oxygen (O2) (30, 40 and 50%) for 15, 30 and 45 days in 5 L (working volume 4 L) airlift bioreactors. Ginsenoside accumulation and dry weight was enhanced up to 40% O2; but thereafter declined ginsenoside and dry weight of the roots by increasing level of O2. Gradual increase in H2O2 content and lipoxygenase activity (LOX), resulting in cellular damage and oxidative stress as indicated by increased malondialdehyde (MDA) content after 30 and 45 days at all O2 levels was shown. Increased levels of O2 (above ambient) resulted in increases in non-protein thiol (NP-SH) and cysteine content. Higher activities of ascorbate peroxidase (APX), monodehydroascorbate reductase (MDHAR), dehydroascorbate reductase (DHAR), glutathione reductase (GR), catalase (CAT), guaiacol peroxidase (G-POD), superoxide dismutase (SOD), glutathione peroxidase (GPx) and glutathione S transferase (GST) activities indicated that antioxidant enzymes played an important role in protecting the roots from O2 up to 45 days, except at 50% O2 where GR, GST and GPx decreased compared to the control. However, after 45 days, SOD activity decreased significantly compared to the control in the O2-treated roots. This reflects the sensitivity of enzymes to O2 toxicity. In stress related experiment, roots showed increased synthesis of ginsenosides when 25 and 50 μM H2O2 was applied. However, higher dose and increasing treatment inhibited ginsenoside synthesis. The results indicate that plant roots could grow and protect themselves from O2 stress by coordinated induction of various antioxidant enzymes and metabolite contents. These results suggest that O2 supplementation is useful for ginsenoside accumulation using 5-L bioreactors.

In vitro regenerated shoots of Spathiphyllum from bioreactor were hydroponically cultured for 30 days. The response of plant growth and photosynthesis to different substrates, photosynthetic photon flux (PPF), nutrient scheduling and electrical conductivity (EC) of hydroponic solution were studied. The best plant growth response was observed in perlite based substrates with moderate PFF (70–100μmol m−2 s−1). Highest fresh weight, dry weight, shoot length, root length, root number and photosynthetic characteristics (chlorophyll, carotenoids and Fv/Fm) was observed in continuous immersion system. Plant growth responses, photosynthetic rate, stomatal conductance and transpiration rate were also found to be affected by EC levels. The optimum EC of a balanced nutrient solution was recorded as 1.2 dS m−1. Photosynthetic activity was also characterized in terms of photochemical efficiency using measurements of chlorophyll fluorescence. Fv/Fm (it is a measure of the intrinsic or maximum efficiency of PSII i.e. the quantum efficiency if all PSII centers were open) also decreased significantly in plants grown under higher EC level; a decrease in this parameter indicates down regulation of photosynthesis or photoinhibition. Antioxidant defense enzymes such as catalase (CAT), ascorbate peroxidase (APX), peroxidase (POD), glutathione reductase (GR) and monodehydroascorbate reductase (MDHAR) significantly elevated in the leaves and roots of plantlets at higher EC levels. This increase could reflect a defense response to the cellular damage provoked by higher EC levels in the nutrient solution.

The oxidative status (anti-oxidative enzymes and anti-oxidants), saponins accumulation H 2 O 2 content and thiobarbituric acid reacting substances (TBARS) of tissue cultured roots of Panax ginseng (PG) and Panax quinquefolium (PQ) exposed to methyl jasmonate (MJ-200 μM) for 0, 3, 5, 7 and 9 days were studied in 5 L (working volume-4 L) airlift bioreactors. Saponin accumulation was enhanced 4-fold higher than the cultivated ginseng by elicitation with MJ without changing dry weight (DW). Decrease in TBARS and dehydroascorbate (DHA) contents along with the induced activity of superoxide dismutase (SOD), guaiacol peroxidase (G-POD) and reduced ascorbate (ASC) contents indicated that anti-oxidant played an important role for protecting plant from MJ elicitation. Seven well-resolved bands of SOD were detected after native polyacrylamide gel electrophoresis (PAGE) analysis, and increase in SOD activity observed in MJ-treated roots seemed to be mainly due to Fe-SOD. One G-POD and two catalase (CAT) isoenzymes (CAT 1 and 2) were also detected in both species significantly. MJ strongly induced G-POD activity and isoenzyme in PG than PQ while CAT activity and isozymes patterns inhibited in both species. Ascorbate peroxidase (APX) in PG and dehydroascorbate reductase (DHAR) in PQ was activated indicating a mechanism of protection from MJ elicitation. In addition, MJ resulted in the decrease of monodehydroascorbate reductase (MDHAR), glutathione reductase (GR), glutathione- S -transferase (GST) and glutathione peroxidase (GPX) activities in both species, which impaired detoxification process. However, GR activity was induced after 9 days of the MJ treatments in PQ. Ascorbate oxidase (AO) activity, ASC contents and ASC/DHA ratio increased after MJ treatment in both species, but DHA content decreased in PQ and remain unchanged in PG compared to control. These data suggest that MJ treatment showed limited oxidative stress in both species, as shown by the decrease in TBARS, in spite of the induction of lipoxygenase (LOX) activity and H 2 O 2 content, which was further correlated with the induced activities of SOD, G-POD, AO and ASC content. Therefore, MJ elicitation is useful for saponin production using 4 L bioreactor root suspension culture.

The effects of different concentrations of CO 2 (1%, 2.5% and 5%) on the antioxidant capacity, total phenols, flavonoids, protein content and phenol biosynthetic enzymes in roots of Panax ginseng were studied in bioreactor (working volume 4 l) after 15, 30 and 45 days. CO 2 induced accumulation of total phenolics in a concentration and duration dependent manner. Total phenols, flavonoids and 1,1-diphenyl-2-picrylhydrazyl (DPPH) activity increased 60%, 30% and 20% at 2.5% CO 2 after 45 days compared to control in P. ginseng roots which indicated that phenolics compounds played an important role in protecting the plants from CO 2 . Hypothesizing that increasing the phenolic compounds in roots of P. ginseng may increase its nutritional functionality; we investigated whether pentose phosphate pathway (PPP), shikimate/phenylpropanoid pathway enzymes have a role in phenolics mobilization in P. ginseng roots. Fresh weight (FW), dry weight (DW) and growth ratio was increased at 1% and 2.5% CO 2 only after 45 days, however, unaffected after 15 and 30 days. Results also indicated that high CO 2 progressively stimulated the activities of glucose 6 phosphate dehydrogenase (G6PDH, E.C. 1.1.1.49), shikimate dehydrogenase (SKDH, E.C. 1.1.1.25), phenylalanine ammonia lyase (PAL, E.C. 4.3.1.5), cinnamyl alcohol dehydrogenase (CAD, E.C. 1.1.1.195), caffeic acid (CA) peroxidase and chlorogenic acid (CGA) peroxidase after 15, 30 and 45 days. Increased CO 2 levels resulted in increases in accumulation of total protein (45%), non-protein thiol (NP-SH) (30%) and cysteine contents (52%) after 45 days compared to control and increased activities of β -glucosidase (GS, E.C. 3.2.1.21) and polyphenol oxidase (PPO, E.C. 1.10.3.2) in P. ginseng roots indicated that they played an important role in protecting the plants from CO 2 . These results strongly suggest that high concentration of CO 2 delivered to ginseng root suspension cultures induced the accumulation of total phenolics possessing high antioxidant properties probably useful for human health. Therefore, roots of P. ginseng are considered as a good source of phenolics compounds with high antioxidants capacity and can be produced on a large scale.

Higher plants growing in natural environments experience various abiotic stresses. The aim of this study was to determine whether exposure to temperature-stress would lead to oxidative stress and whether this effect varied with different exposure periods. The thermal dependencies of the activities of protective enzymes, photosynthetic efficiency (Fv/Fm), protein, non-protein thiol (NP-SH), cysteine content, lipoxygenase (LOX) activity (EC 1.13.11.12) and malondialdehyde (MDA) content at 25-40 degrees C were determined for 4, 24 and 48 h in leaf and root segments of Phalaenopsis. The increase in MDA level and LOX activity may be due to temperature-associated oxidative damage to leaf and root segments. Temperature-stress induced not only activities of active oxygen species (AOS) scavenging enzymes but also protein, NP-SH and cysteine content in both leaf and root segments at 30 degrees C for 4 and 24 h (except for 48 h in some cases) compared to 25 degrees C-and greenhouse-grown leaf and root segments indicating that antioxidants enzymes played an important role in protecting plant from temperature-stress. However, activities of dehydroascorbate reductase (DHAR, EC 1.8.5.1), glutathione peroxidase (GPX, EC 1.11.1.9) and glutathione-S-transferase (GST, EC 2.5.1.18) in leaf and root, glutathione reductase (GR, EC 1.6.4.2) in leaf and guaiacol peroxidase (G-POD, 1.11.1.7) in root segments were induced significantly at 40 degrees C compared to 25 degrees C and greenhouse-grown plants suggesting that these enzymes play protective roles at high temperature. In contrast, activities of superoxide dismutase (SOD, EC 1.15.1.1) and monodehydroascorbate reductase (MDHAR, EC 1.6.5.4) in leaf and root, catalase (CAT, EC 1.11.1.6) in root, GR in root, and protein, cysteine, NP-SH content in both root and leaf and Fv/Fm ratio were diminished significantly at 40 degrees C compared to 25 degrees C-and greenhouse-grown plants. These indicate that these enzymes were apparently not involved in detoxification process and sensitive at higher temperature. Also, the close relation between activities of enzymes with their metabolites at 30 degrees C than 40 degrees C indicated that the antioxidants enzymes and metabolites both may play an important role in protecting cells against the temperature-stress.

Plants of Cassia siamea Lamk were grown in garden soil (control), fly-ash (100%) and fly-ash amended by various ameliorants (cowdung manure, press-mud, garden soil; 1:1, w/w). The plants survived in fly-ash (100%) though their growth was less in comparison to the treatments. Fly-ash + press-mud (1:1, w/w) proved to be the best combination as growth (total biomass, leaf number, photosynthetic area, total chlorophyll and protein) was significantly high in this treatment followed by cowdung manure and garden soil. Leaves and roots accumulated significant amount of Cu, Zn, Ni and and Fe. However, the concentration of all the metals was more in roots than leaves except Ni. Although, fly-ash contains high amount of metals but the metal uptake was more in the plants grown in fly-ash + press-mud mixture. Inspite of high metal availability in fly-ash and press-mud mixture, plant growth was good. This might be attributed to the some metal detoxification mechanism active in this treatment. The present study concluded that C. siamea seems to be a suitable plant for developing a vegetation cover on fly-ash dumps.

We studied how the relationship between cadmium (Cd) toxicity and oxidative stress influenced the growth, photosynthetic efficiency, lipid peroxidation, and activity of ntioxidative enzymes in the roots and leaves of rice(Oryza sativa L Dongjin). Plants were exposed to Cd for 21 d. Both seedling growth and photosynthetic efficiency decreased gradually with increasing cadmium concentrations. Lipid peroxidation increased slowly in both roots and leaves, causing oxidative stress. However, each tissue type responded differently to Cd concentrations with regard to the induction/ inhibition of antioxidative enzymes. The activity of Superoxide dismutase (SOD) increased in both roots and leaves. Ascorbate peroxidase (APX) activity increased in leaves treated with up to 0.25 µM Cd, then decreased gradually at higher concentrations. In contrast, APX activity in roots increased and remained constant between 0.25 and 25 µM Cd. Enhanced peroxidase (POD) activity was recorded for treatments with up to 25/M Cd, gradually decreasing at higher concentrations in the leaves but remaining unchanged in the roots. Catalase (CAT) activity increased in the roots, but decreased in the leaves, whereas the activity of glutathione reductase (GR) was enhanced in both roots and leaves, where it remained elevated at higher Cd concentrations. These results suggest that rice seedlings tend to cope with free radicals generated by Cd through coordinated, enhanced activities of the antioxidative enzymes involved in detoxification.

We studied the effects of different concentrations of mercury (0.0 to 100 µM) on growth and photosynthetic efficiency in rice plants treated for 21 d. In addition, we investigated how this metal affected the malondialdehyde (MDA) content as well as the activity of five antioxidant enzymes — superoxide dismutase (SOD), ascorbate peroxidase (APX), glutathione reductase (GR), guaiacol peroxidase (POD), and catalase (CAT). Photosynthetic efficiency (Fµ/Fm) and seedling growth decreased as the concentration of Hg was increased in the growth media. Plants also responded to Hg-induced oxidative stress by changing the levels of their antioxidative enzymes. Enhanced lipid peroxidation was observed in both leaves and roots that had been exposed to oxidative stress, with leaves showing higher enzymatic activity. Both SOD and APX activities increased in treatments with up to 50 µM Hg, then decreased at higher concentrations. In the leaves, both CAT and POD activities increased gradually, with CAT levels decreasing at higher concentrations. In the roots, however, CAT activity remained unchanged while that of POD increased a bit more than did the control for concentrations of up to 10 µM Hg. At higher Hg levels, both CAT and POD activities decreased. GR activity increased in leaves exposed to no more than 0.25 µM Hg, then decreased gradually. In contrast, its activity was greatly inhibited in the roots. Based on these results, we suggest that when rice plants are exposed to different concentrations of mercury, their antioxidative enzymes become involved in defense mechanisms against the free radicals that are induced by this stress.

The level of toxic metals Cr, Cd, Pb and Cu was determined in seeds, water and sediments collected from nine closed waterbodies of Darbhanga, north Bihar, used for cultivation of the edible aquatic macrophyte Euryale ferox Salisb. during harvesting season of the crop for two successive years (1996 and 1997). Seeds bioconcentrated appreciable amount of these toxic metals in the order Pb>Cr>Cu>Cd. The increased load of metal pollution due to domestic and municipal discharges threatened the habitats of the plant. The toxic metal contents in seeds were found positively correlated with the ambient concentration of metals in water and sediments. The importance of these findings has been discussed for national water resource economy of the country and human health perspectives.

Lake Nainital is the sole source of drinking water for the local people and even to majority of tourists. In background of lake utility and its importance at national level, such study is essential which is focused on toxic metal pollution and current nutrient status of the lake and their magnification by algae and macrophytes. Study has shown that lake water is rich in nutrients which supports growth of many aquatic macrophytes and algal blooms. Besides, water is contaminated with metals like Cr, Cu, Fe, Mn, Ni, Pb and Zn. Concentration of some of them like Fe, Pb and Ni were higher than the recommended maximum permissible limits. Concentration of these metals were also found high in lake sediments. The level of metals amongst various components of lake varied considerably in different season. Plants and algae growing therein accumulated appreciable amount of metals and water roots of Salix being more efficient than others. High metal removing potential of these plants may be significant for biomonitoring studies and could be a useful phytoremediation technology to restore water quality by harvesting submerged and floating biomass inhabiting littoral zone of the lake.

Secondary metabolites (SMs) are organic molecules that have a wide range of chemical structures and biological functions. SMs, especially flavonoid, have been recently suggested in playing important roles as antioxidants. They appear to be induced by a variety of environmental factors including fungal elicitors, light, ultraviolet radiation, interactions with microorganisms, wounding, metal stress, temperature changes, drought and nutrient depletion. These molecules are commonly synthesized in different parts of the plant (cells, leaves, stem, roots, vacuole of plant cells) and protect the plant against adverse conditions, such as microbial and herbivore attacks. Some SMs had a significant impact on human health as they are important components of the daily diet and may help prevent human diseases. The structural and regulatory genes play important roles in the biosynthesis of secondary metabolites. In this chapter, recent research developments on the structural genes and regulatory genes that are involved in the biosynthesis of SMs and plant developments are discussed, focusing on the flavonoid biosynthesis pathway.

Background The complex and dynamic changes during grape berry development have been studied in Vitis vinifera, but little is known about these processes in other Vitis species. The grape variety 'Norton', with a major portion of its genome derived from Vitis aestivalis, maintains high levels of malic acid and phenolic acids in the ripening berries in comparison with V. vinifera varieties such as Cabernet Sauvignon. Furthermore, Norton berries develop a remarkably high level of resistance to most fungal pathogens while Cabernet Sauvignon berries remain susceptible to those pathogens. The distinct characteristics of Norton and Cabernet Sauvignon merit a comprehensive analysis of transcriptional regulation and metabolite pathways. Results A microarray study was conducted on transcriptome changes of Norton berry skin during the period of 37 to 127 days after bloom, which represents berry developmental phases from herbaceous growth to full ripeness. Samples of six berry developmental stages were collected. Analysis of the microarray data revealed that a total of 3,352 probe sets exhibited significant differences at transcript levels, with two-fold changes between at least two developmental stages. Expression profiles of defense-related genes showed a dynamic modulation of nucleotide-binding site-leucine-rich repeat (NBS-LRR) resistance genes and pathogenesis-related (PR) genes during berry development. Transcript levels of PR-1 in Norton berry skin clearly increased during the ripening phase. As in other grapevines, genes of the phenylpropanoid pathway were up-regulated in Norton as the berry developed. The most noticeable was the steady increase of transcript levels of stilbene synthase genes. Transcriptional patterns of six MYB transcription factors and eleven structural genes of the flavonoid pathway and profiles of anthocyanins and proanthocyanidins (PAs) during berry skin development were analyzed comparatively in Norton and Cabernet Sauvignon. Transcriptional patterns of MYB5A and MYB5B were similar during berry development between the two varieties, but those of MYBPA1 and MYBPA2 were strikingly different, demonstrating that the general flavonoid pathways are regulated under different MYB factors. The data showed that there were higher transcript levels of the genes encoding flavonoid-3'-O-hydroxylase (F3'H), flavonoid-3',5'-hydroxylase (F3'5'H), leucoanthocyanidin dioxygenase (LDOX), UDP-glucose:flavonoid 3'-O-glucosyltransferase (UFGT), anthocyanidin reductase (ANR), leucoanthocyanidin reductase (LAR) 1 and LAR2 in berry skin of Norton than in those of Cabernet Sauvignon. It was also found that the total amount of anthocyanins was markedly higher in Norton than in Cabernet Sauvignon berry skin at harvest, and five anthocyanin derivatives and three PA compounds exhibited distinctive accumulation patterns in Norton berry skin. Conclusions This study provides an overview of the transcriptome changes and the flavonoid profiles in the berry skin of Norton, an important North American wine grape, during berry development. The steady increase of transcripts of PR-1 and stilbene synthase genes likely contributes to the developmentally regulated resistance during ripening of Norton berries. More studies are required to address the precise role of each stilbene synthase gene in berry development and disease resistance. Transcriptional regulation of MYBA1, MYBA2, MYB5A and MYBPA1 as well as expression levels of their putative targets F3'H, F3'5'H, LDOX, UFGT, ANR, LAR1, and LAR2 are highly correlated with the characteristic anthocyanin and PA profiles in Norton berry skin. These results reveal a unique pattern of the regulation of transcription and biosynthesis pathways underlying the viticultural and enological characteristics of Norton grape, and yield new insights into the understanding of the flavonoid pathway in non-vinifera grape varieties.

A chicken growth study was conducted to determine if litter type influenced gut microbiota and performance in broilers. Seven bedding materials were investigated and included soft and hardwood sawdust, softwood shavings, shredded paper, chopped straw, rice hulls, and reused softwood shavings. Microbial profiling was done to investigate changes in cecal bacterial communities associated with litter material and age. Cecal microbiota were investigated at 14 and 28 d of age (n = 12 birds/litter material). At both ages, the cecal microbiota of chickens raised on reused litter was significantly (P0.05) different from that of chickens raised on any of the other litter materials, except softwood shavings at d 28. Cecal microbiota was also significantly different between birds raised on shredded paper and rice hulls at both ages. Age had a significant influence on cecal microbiota composition regardless of litter material. Similarity in cecal microbial communities among birds raised on the same litter treatment was greater at 28 d of age (29 to 40%) than at 14 d of age (25 to 32%). Bird performance on the different litter materials was measured by feed conversion ratio, live weight, and feed intake. Significant (P0.05) differences were detected in live weight at 14 d of age and feed intake at 14 and 28 d of age among birds (n = 160/treatment) raised on some of the different litter materials. However, no significant (P0.05) differences were observed in feed conversion ratio among birds raised on any of the 7 different litter materials at either 14 or 28 d of age. The type of litter material can influence colonization and development of cecal microbiota in chickens. Litter-induced changes in the gut microbiota may be partially responsible for some of the significant differences observed in early rates of growth; therefore, litter choice may have an important role in poultry gut health particularly in the absence of in-feed antibiotics.

Vitis vinifera (grapevine) is the most economically important deciduous fruit crop, but cultivated grapevine varieties lack adequate innate immunity to a range of devastating diseases. To identify genetic resources for grapevine innate immunity and understand pathogen defense pathways in a woody perennial plant, we focus in this study on orthologs of the central Arabidopsis thaliana defense regulator ENHANCED DISEASE SUSCEPTIBILITY1 (EDS1). The family of EDS1-like genes is expanded in grapevine, and members of this family were previously found to be constitutively upregulated in the resistant variety 'Norton' of the North American grapevine species Vitis aestivalis, while they were induced by Erysiphe necator, the causal agent of grapevine powdery mildew (PM), in the susceptible V. vinifera variety 'Cabernet Sauvignon'. Here, we determine the responsiveness of individual EDS1-like genes in grapevine to PM and salicylic acid, and find that EDS1-like paralogs are differentially regulated in 'Cabernet Sauvignon', while two are constitutively upregulated in 'Norton'. Sequencing of VvEDS1 and VaEDS1 cDNA and genomic clones revealed high conservation in the protein-encoding sequence and some divergence of the promoter sequence in the two grapevine varieties. Complementation of the Arabidopsis eds1-1 mutant showed that the EDS1-like gene with highest predicted amino acid sequence similarity to AtEDS1 from either grapevine varieties is a functional ortholog of AtEDS1. Together, our analyses show that differential susceptibility to PM is correlated with differences in EDS1 expression, not differences in EDS1 function, between resistant 'Norton' and susceptible 'Cabernet Sauvignon'.

To investigate the enzyme variations responsible for the synthesis of phenolics, 40 day-old adventitious roots of Panax ginseng were treated with 200 microM methyl jasmonate (MJ) or salicylic acid (SA) in a 5 L bioreactor suspension culture (working volume 4 L). Both treatments caused an increase in the carbonyl and hydrogen peroxide (H2O2) contents, although the levels were lower in SA treated roots. Total phenolic, flavonoid, ascorbic acid, non-protein thiol (NPSH) and cysteine contents and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical reducing activity were increased by MJ and SA. Fresh weight (FW) and dry weight (DW) decreased significantly after 9 days of exposure to SA and MJ. The highest total phenolics (62%), DPPH activity (40%), flavonoids (88%), ascorbic acid (55%), NPSH (33%), and cysteine (62%) contents compared to control were obtained after 9 days in SA treated roots. The activities of glucose 6-phosphate dehydrogenase, phenylalanine ammonia lyase, substrate specific peroxidases (caffeic acid peroxidase, quercetin peroxidase and ferulic acid peroxidase) were higher in MJ treated roots than the SA treated ones. Increased shikimate dehydrogenase, chlorogenic acid peroxidase and beta-glucosidase activities and proline content were observed in SA treated roots than in MJ ones. Cinnamyl alcohol dehydrogenase activity remained unaffected by both MJ and SA. These results strongly indicate that MJ and SA induce the accumulation of phenolic compounds in ginseng root by altering the phenolic synthesis enzymes.

Roots of Panax ginseng exposed to various concentrations of Cu (0.0, 5, 10.0, 25.0, and 50.0 microM) accumulated high amounts of Cu in a concentration-dependent and duration-dependent manner. Roots treated with 50 microM Cu resulted in 52% and 89% growth inhibition after 20 and 40 days, respectively. Saponin synthesis was stimulated at a Cu concentration between 5 and 25 muM but decreased at 50 microM Cu. Malondialdehyde content (MDA), lipoxygenase activity (LOX), superoxide ion (O2*-) accumulation, and H2O2 content at 5 and 10 microM Cu-treated roots were not increased but strongly increased at 50 microM Cu resulting in the oxidation of ascorbate (ASC) and glutathione (GSH) to dehydroascorbate (DHA) and glutathione disulfide (GSSG), respectively indicating a clear oxidative stress. Seven well-resolved bands of superoxide dismutase (SOD) were detected in the gel and an increase in SOD activity seemed to be mainly due to the induction of Fe-SOD 3. Five to 10 microM Cu slightly induced activity of ascorbate peroxidase (APX) and dehydroascorbate reductase (DHAR), guaiacol peroxidase (G-POD) but inhibited monodehydroascorbate reductase (MDHAR) and glutathione reductase (GR) enzyme activities. No changes in catalase (CAT) activity and in activity gel were found up to 25 microM Cu, but both G-POD and CAT activities were inhibited at 50 microM Cu. Glutathione metabolism enzymes such as gamma-glutamylcysteine synthetase (gamma-GCS), glutathione-S-transferase (GST), and glutathione peroxidase activities (GPx) were activated at 5 and 10 microM Cu but were strongly inhibited at 50 microM Cu due to the Cu accumulation in root tissues. The strong depletion of GSH at 50 microM Cu was associated to the strong induction of gamma-glutamyltranspeptidase (gamma-GGT) activity. These results indicate that plant could grow under Cu stress (5-25 microM) by modulating the antioxidant defense mechanism for combating Cu induced oxidative stress.

The effects of methyl jasmonate (MJ) and salicylic acid (SA) on changes of the activities of major antioxidant enzymes, superoxide anion accumulation (O2-), ascorbate, total glutathione (TG), malondialdehyde (MDA) content and ginsenoside accumulation were investigated in ginseng roots (Panax ginseng L.) in 4 l (working volume) air lift bioreactors. Single treatment of 200 microM MJ and SA to P. ginseng roots enhanced ginsenoside accumulation compared to the control and harvested 3, 5, 7 and 9 days after treatment. MJ and SA treatment induced an oxidative stress in P. ginseng roots, as shown by an increase in lipid peroxidation due to rise in O2- accumulation. Activity of superoxide dismutase (SOD) was inhibited in MJ-treated roots, while the activities of monodehydroascorbate reductase (MDHAR), dehydroascorbate reductase (DHAR), SOD, guaiacol peroxidase (G-POD), glutathione peroxidase (GPx) and glutathione reductase (GR) were induced in SA-treated roots. A strong decrease in the activity of catalase (CAT) was obtained in both MJ- and SA-treated roots. Activities of ascorbate peroxidase (APX) and glutathione S transferase (GST) were higher in MJ than SA while the contents of reduced ascorbate (ASC), redox state (ASC/(ASC+DHA)) and TG were higher in SA- than MJ-treated roots while oxidized ascorbate (DHA) decreased in both cases. The result of these analyses suggests that roots are better protected against the O2- stress, thus mitigating MJ and SA stress. The information obtained in this work is useful for efficient large-scale production of ginsenoside by plant-root cultures.

Plants of Nymphaea alba L. grown at various levels of chromium (VI) ranging from 1 to 200 microM accumulated chromium in concentration and duration-dependent manner. At all Cr levels, chromium accumulation by various plant tissues followed the order rootsleavesrhizomes. Approximately 93% of total chromium present in the medium was accumulated by plants at lowest conentration (1 microM) used in the experiment. Chromium-induced toxicity appears at 1 microM chromium resulting in the build-up of delta-aminolevulinic acid (ALA) and reduced activities of delta-aminolevulinic acid dehydratase (ALAD) and nitrate reductase (NR), total chlorophyll (Chl) and protein contents. Ch1a was more sensitive than Ch1b to chromium toxicity. It could be inferred that chromium toxicity is not located at the level of ALA synthesis, but, probably at the ALAD activity which was more severely affected during chlorophyll biosynthesis. Finally, impaired chlorophyll biosynthesis resulted in reduced total chlorophyll content.

Background The production and use of biologically derived soil additives is one of the fastest growing sectors of the fertilizer industry. These products have been shown to improve crop yields while at the same time reducing fertilizer inputs to and nutrient loss from cropland. The mechanisms driving the changes in primary productivity and soil processes are poorly understood and little is known about changes in secondary productivity associated with the use of microbial products. Here we investigate secondary metabolic responses to a biologically derived soil additive by monitoring changes in the phenlypropanoid (PP) pathway in Arabidopsis thaliana. Results This study was designed to test the influence of one of these products (Soil Builder™-AF, SB) on secondary metabolism after being applied at different times. One time (TI) application of SB to Arabidopsis increased the accumulation of flavonoids compared to multiple (TII) applications of the same products. Fourteen phenolic compounds including flavonols and anothocyanins were identified by mass spectrometry. Kaempferol-3,7-O-bis-α-L-rhamnoside and quercetin 3,7-dirhamnoside, the major compounds, increased 3-fold and 4-fold, respectively compared to control in the TI treatment. The most abundant anthocyanin was cyanidin 3-rhamnoglucoside, which increased 3-fold and 2-fold in TI compared to the control and TII, respectively. Simultaneously, the expression of genes coding for key enzymes in the PP pathway (phenylalanine ammonia lyase, cinnamate 4-hydroxylase, chalcone synthase, flavonoid-3′-O-hydroxylase, flavonol synthase1 and dihydroflavonol-4-reductase) and regulatory genes (production of anthocyanin pigment2, MYB12, MYB113, MYB114, EGL3, and TT8) were up-regulated in both treatments (TI and TII). Furthermore, application of TI and TII induced expression of the lignin pathway genes (hydroxyl cinamyl transferase, caffeyl-CoA O-methyl transferase, cinnamyl alcohol dehydrogenase, cinnamyl-CoA reductase, secondary wall-associated NAC domain protein1, MYB58 and MYB63 resulting in higher accumulation of lignin content compared to the control. Conclusions These results indicate that the additions of microbially based soil additives have a perceptible influence on phenylpropanoid pathway gene regulation and its production of secondary metabolites. These findings open an avenue of research to investigate the mode of action of microbially-based soil additives which may assist in the sustainable production of food, feed, fuel and fiber.