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Coronatine (COR), a functional analogue of jasmonates, affects the accumulation of defense-related metabolites in plants. However, information on how its effects may be mediated by heavy metal stress is scanty. This study was carried out to determine the changes in some physiological parameters in sweet basil (Ocimum basilicum L.) seedlings pretreated with COR under arsenic (As) toxicity. COR was applied to seedlings at the three-leaf stage at 50 and 100 nanomolars (nmol x [L.sup.- 1]). Arsenic at 150 and 300 µmol x [L.sup.-1] was imposed after completion of COR treatment. Toxic effects of As were reflected by the reduction in growth parameters and photosynthetic pigments and induction of lipid peroxidation coupled with enhancing hydrogen peroxide and electrolyte leakage in leaves. Under As toxicity, plants treated with COR significantly increased the fresh mass and relative water content in leaves. The increase was accompanied by decreased lipid peroxidation and hydrogen peroxide content and maintenance of chlorophyll pigments. COR supplement also increased the accumulation of phenolic compounds and proline content in the leaf of As-treated seedlings. Pretreatment with COR significantly enhanced activities of catalase (CAT), superoxide dismutase (SOD), and guaiacol peroxidase (POD) in basil leaves under As treatment. The results suggested that COR might alleviate As toxicity in sweet basil by activating antioxidant enzymes and inducing conservative components, thereby preventing membrane peroxidation. Key words: arsenic, coronatine, growth, toxicity, sweet basil. La coronatine (COR), un analogue fonctionnel des jasmonates, affecte l'accumulation des metabolites relies a la defense chez les plantes. Cependant, il existe peu d'information sur la fa^on elle peut intervenir sous un stress metallique. Les auteurs ont cherche a determiner les changements de certains parametres physiologiques chez des plantules de basilic (Ocimum basilicum L.) pretraitees avec de la COR, sous des conditions de toxicite en arsenic (As). Ils ont applique la COR sur les plantules au stade trois feuilles, a 50 et 100 nanomolaire (nmol x [L.sup.-1]). Suite au traitement a la COR, ils ont applique de l'As a 150 et 300 µmol x [L.sup.-1]. Les effets de l'As se sont traduits par la reduction des parametres de croissance et des pigments photosynthetiques, ainsi qu'une induction de peroxydation des lipides couplee avec une augmentation du peroxyde d'hydrogene et d'une perte d'electrolytes. Sous l'effet toxique de l'As, les plantes traitees avec la COR augmentent significativement leur poids frais et la teneur relative en eau dans leurs feuilles. L'accroissement s'accompagne d'une diminution de la peroxydation des lipides et de la teneur en peroxyde, ainsi qu'un maintien des pigments chlorophylliens. Un supplement de COR augmente egalement l'accumulation de substances phenoliques et de la teneur en proline dans la feuille des plantules traitees a l'As. Un pretraitement avec la COR augmente significativement les activites de la catalase (CAT), de la superoxyde dismutase (SOD) et de la peroxydase du gauaicol (POD) chez les feuilles du basilic sous traitement a l'As. Les resultats suggerent que la COR pourrait empecher la toxicite chez le basilic en activant des enzymes antioxydantes et en induisant des composes conservateurs, prevenant ainsi la peroxydation des membranes. [Traduit par la Redaction] Mots-cles: arsenic, coronatine, croissance, toxicite, basilic., Introduction Arsenic (As) contaminated soils are a major source of food contamination and thereby endanger human health because this metalloid is known to be a carcinogen and remains in the [...]

The interaction between nanoparticles and plants is inevitable. In this study, the effect of different concentrations of ZnO nanoparticles synthesised using olive extract on the soybean was studied. The soybean seeds were cultured in a Hoagland medium containing agar which was treated different concentrations (0, 200 and 400 ppm) of ZnO nanoparticles. After 21 days, the plants were harvested and the parameters of proline, anthocyanin, malondialdehyde (MDA), hydrogen peroxide (H2 O2), chlorophyll and carotenoid contents and phenylalanine ammonia‐lyase (PAL) and catalase (CAT) activity in soybeans (Glycine max) were measured. The results showed that the levels of chlorophyll a and b and carotenoid at concentrations of 200 and 400 ppm in comparison with control decreased, while carotenoid content at 200 ppm concentration at a concentration of 400 ppm was not significant. The level of anthocyanin and PAL activity increased with increasing concentration of nanoparticles, while proline content decreased. By increasing the concentration of ZnO nanoparticles, the content of MDA and hydrogen peroxide increased compared to control but CAT activity did not change significantly. This research suggests that ZnO nanoparticles synthesised using olive extract in soybean plants may be toxic by reactive oxygen species production. [ABSTRACT FROM AUTHOR]

In this study, triacontanol (TRIA) and nitric oxide (NO) interaction on arsenic (As)-induced oxidative stress tolerance in coriander (Coriandrum sativumL.) plants was investigated. The results showed that As had a significant adverse effect on the plant’s biomass. The seedlings pretreated with TRIA and NO significantly increased growth reduction induced by the metalloid. The obtained results indicated that the application of TRIA and sodium nitroprusside (SNP) generally reduced oxidative markers such as of electrolyte leakage percentage, malondialdehyde and H2O2contents under As toxicity, while application of As treatment without TRIA + SNP increased these oxidative parameters compared to the control. The non-enzymatic antioxidant contents such as total phenol, anthocyanin, carotenoid, ascorbic acid and reduced glutathione (GSH) were extracted and assayed from both control and treated plants. It was found that TRIA + SNP treatments have a profound effect on the antioxidant metabolism and caused an enhancement in non-enzymatic antioxidant potentials under As toxicity in coriander. Moreover, the results revealed a mutually amplifying reaction between TRIA and NO in reducing As-induced damages. [ABSTRACT FROM PUBLISHER]

This study was carried out to evaluation of some nutrients accumulation including Ni (nickel), Fe (iron), Mg (magnesium), Cu (copper), Ca (calcium) as well as Ni translocation factor (TF) in three tomato cultivars grown hydroponically under treatments including L-histidine (His) and calcium chloride (CaCl2) (300 µM) exposed to nickel (II) sulfate (NiSO4) (150 and 300 µM) by ICP-OES (inductively coupled plasma atomic emission spectroscopy) analysis. Tomato cultivars included Cal-J N3, Early Urbana Y and. Results indicated that shoot Ni accumulation increased under Ni stress. Ca and His reduced root, shoot Ni content and Ni TF (translocation factor) under Ni stress in Petoearly CH cultivar. Ni stress also decreased root and shoot Ca, Fe, Mg and Cu while Ca and His improved the nutrients uptake, and inhibited Ni accumulation. Therefore, Ca and His alleviated adverse effects of Ni stress on nutrients in Petoearly CH cultivar. Beside, Ca and His interaction alleviate Ni stress by inhibition of Ni uptake and translocation as well as plant nutrition improvement in the tomato plants. [ABSTRACT FROM AUTHOR]

In the present study we investigated the effect of ethephon on changes in the amount of many terpenoid compounds including, tetrahydrocannabinol (THC), cannabidiol (CBD), chlorophyll, carotenoids, α-tocopherol and pyruvate as one of substrate in plastidic terpenoids biosynthesis inCannabis sativaat vegetative stage. Treatment with 1 and 100 µM ethephon increased THC content up to 9 fold in vegetative stage. Plants treated with 10 µM ethephon had more CBD content in comparison with control plants. The amount of CBD decreased in plants subjected to 5 and 100 µM ethephon. Leave area in plant treated with ethephon did not show significant changes in comparison to control plants. Ethephon treatment caused a declined in the amount of α-tocopherol. The levels of chlorophylls and carotenoids raised in treated plants with 1 µM ethephon. With regard to the fact that ethephon had not negative effect on the surface of leaves and chlorophyll content thus its application can be a suitable way for increasing of THC and α-tocopherol inCannabis sativaL. [ABSTRACT FROM AUTHOR]

Bacteria-Plant systems for bioremediation of oil polluted sites are one of the most effective approaches of biotechnology in the recent years. It is well known that oil pollution induces oxidative stress in plants. In this research, the effects of crude oil pollution on Zea mays and bioremediation by synergism between plant and crude oil degrading bacteria, four different treatments were designed. Some physiological and microbial factors were assayed for determining the effects of oil pollution. The results showed that 1% crude oil in soil shoot, dry weight was reduced and the amount of phenolic compounds increased. With crude oil and Pseudomonas aeruginosa bacterium, shoot dry weight, chlorophyll (a), total chlorophyll and anthocyanins decreased wherase phenolic compounds, malodialdehyde and catalase enzyme activity increased. With 1% crude oil and Acinetobacter calcoaceticus bacterium, significant changes were seen in the parameters of growth. Photosynthetic pigment did not increase whereas anthocyanin, phenolic compounds, malodialdehyde and catalase activity increased. White Crude oil and the presence of both bacteria shoot dry weight and chlorophyll levels decreased and increased levels of anthocyanin and malon-dialdehyde were observed. Addition of oil to the soil, increased the numbers of crude oil degrading bacteria and heterotrophic bacteria but crude oil were removed from soil by biodegradation. By application of bacterialplant systems in the field, industrial wastes from refinery and biochemical factories could be removed oppropriately. [ABSTRACT FROM AUTHOR]

Plants synthesize an astonishing diversity of isoprenoids, some of which play essential roles in photosynthesis, respiration, and the regulation of growth and development. Two independent pathways for the biosynthesis of isoprenoid precursors coexist within the plant cell: the cytosolic mevalonic acid (MVA) pathway and the plastidial methylerythritol phosphate (MEP) pathway. However, little is known about the effects of plant hormones on the regulation of these pathways. In the present study we investigated the effect of gibberellic acid (GA3) on changes in the amounts of many produced terpenoids and the activity of the key enzymes, 1-deoxy-D-xylulose 5-phosphate synthase (DXS) and 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGR), in these pathways. Our results showed GA3 caused a decrease in DXS activity in both sexes that it was accompanied by a decrease in chlorophylls, carotenoids and Δ9-tetrahydrocannabinol (THC) contents and an increase in α-tocopherol content. The treated plants with GA3 showed an increase in HMGR activity. This increase in HMGR activity was followed by accumulation of stigmasterol and β-sitosterol in male and female plants and campestrol in male plants. The pattern of the changes in the amounts of sterols was exactly similar to the changes in the HMGR activity. These data suggest that GA3 can probably influence the MEP and MVA pathways oppositely, with stimulatory and inhibitory effects on the produced primary terpenoids in MVA and DXS pathways, respectively. [ABSTRACT FROM AUTHOR]

Plants synthesize an astonishing diversity of isoprenoids, some of which play essential roles in photosynthesis, respiration, and the regulation of growth and development. Two independent pathways for the biosynthesis of isoprenoid precursors coexist within the plant cell: the cytosolic mevalonic acid (MVA) pathway and the plastidial methylerythritol phosphate (MEP) pathway. However, little is known about the effects of plant hormones on the regulation of these pathways. In the present study we investigated the effect of gibberellic acid (GA(3)) on changes in the amounts of many produced terpenoids and the activity of the key enzymes, 1-deoxy-D-xylulose 5-phosphate synthase (DXS) and 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGR), in these pathways. Our results showed GA(3) caused a decrease in DXS activity in both sexes that it was accompanied by a decrease in chlorophylls, carotenoids and Delta(9)-tetrahydrocannabinol (THC) contents and an increase in alpha-tocopherol content. The treated plants with GA(3) showed an increase in HMGR activity. This increase in HMGR activity was followed by accumulation of stigmasterol and beta-sitosterol in male and female plants and campestrol in male plants. The pattern of the changes in the amounts of sterols was exactly similar to the changes in the HMGR activity. These data suggest that GA(3) can probably influence the MEP and MVA pathways oppositely, with stimulatory and inhibitory effects on the produced primary terpenoids in MVA and DXS pathways, respectively.