Fusicoccin Counteracts the Toxic Effect of Cadmium on the Growth of Maize Coleoptile Segments

The effects of cadmium (Cd; 0.1–1000 μM) and fusicoccin (FC) on growth, Cd2+ content, and membrane potential (Em) in maize coleoptile segments were studied. In addition, the Em changes and accumulation of Cd and calcium (Ca) in coleoptile segments treated with Cd2+ combined with 1 μM FC or 30 mM tetraethylammonium (TEA) chloride (K+-channel blocker) were also determined. In this study, the effects of Ca2+-channel blockers [lanthanum (La) and verapamil (Ver)] on growth and content of Cd2+ and Ca2+ in coleoptile segments were also investigated. It was found that Cd at high concentrations (100 and 1000 μM) significantly inhibited endogenous growth of coleoptile segments and simultaneously measured proton extrusion. FC combined with Cd2+ counteracted the toxic effect of Cd2+ on endogenous growth and significantly decreased Cd2+ content (not the case for Cd2+ at the highest concentration) in coleoptile segments. Addition of Cd to the control medium caused depolarization of Em, the extent of which was dependent on Cd concentration and time of treatment with Cd2+. Hyperpolarization of Em induced by FC was suppressed in the presence of Cd2+ at 1000 μM but not Cd2+ at 100 μM. It was also found that treatment of maize coleoptile segments with 30 mM TEA chloride caused hyperpolarization of Em and decreased Cd2+ content in coleoptile segments, suggesting that, in the same way as for FC, accumulation of Cd2+ was dependent on plasma membrane (PM) hyperpolarization. Similar to FC, TEA chloride also decreased Ca2+ content in coleoptile segments. La and Ver combined with Cd2+ (100 μM) significantly decreased Cd content in maize coleoptile segments, but only La completely abolished the toxic effect of Cd2+ on endogenous growth and growth in the presence of FC. Taken together, these results suggest that the mechanism by which FC counteracts the toxic effect of Cd2+ (except at 1000 μM Cd2+) on the growth of maize coleoptile segments involves both stimulation of PM H+-ATPase activity by FC as well as Cd2+-permeable, voltage-dependent Ca channels, which are blocked by FC and TEA chloride-induced PM hyperpolarization

Physiological and biochemicals changes modulated by seeds’ priming of lentil (Lens culinaris L.) under salt stress at germination stage

Seed priming is one of the potential physiological approaches to enhance the seed germination under the salinity stress. The present study examined the role of two seed priming molecules: salicylic acid (SA) and hydrogen peroxide (H2O2), in enhancing the salt tolerance of lentil seeds at germination stage. Salinity stress caused significant decrease in germination percentage and primary root elongation. This decrease was associated with significant increase in lipid peroxidation and total lipid (TL) contents in embryonic axis. The catalase (CAT), guaiacol peroxydase (GPOX) and superoxide dismutase (SOD) activities remained unchanged or decreased significantly under the influence of salt stress, in both embryonic axis and cotyledons. Starch mobilization was not affected by the salt stress. The two priming treatments effectively alleviated the negative effects of salinity stress. SA and H2O2 applications after dose optimization resulted in a significant enhancement of germination percentage and primary root elongation. No significant changes in starch, soluble sugars contents and SOD activity were detected following SA and H2O2 treatments. Seed priming treatments triggered the activities of GPOX and CAT and caused the reduction in lipid peroxidation, especially in embryonic axis. TL content and especially the fatty acid C18:3 increased after SA applications. Better performance under salt stress of primed lentil seeds was associated with lower lipid peroxidation, and activation of enzymatic antioxidative defense system. Obtained results confirm the potential for using SA and H2O2 to improve germination and plant growth under salt stress conditions

Effets du cadmium sur l'accumulation ionique et les teneurs en lipides dans les feuilles de tomate (

L'objectif de ce travail a été d'évaluer l'accumulation du cadmium au niveau des feuilles âgées et des feuilles jeunes ainsi que ses effets sur la croissance, la nutrition minérale, la synthèse des pigments photosynthétiques et la composition lipidique chez la tomate préalablement cultivée sur milieu nutritif de base puis traitée pendant une semaine avec des doses croissantes de CdCl2 (0, 1, 5, 10, 25 et 50 $\mu$M). Malgré la forte accumulation de Cd dans les feuilles âgées, la croissance de ces dernières est moins affectée que celle des feuilles jeunes. Le cadmium diminue les teneurs en éléments nutritifs ainsi que celles des pigments photosynthétiques. L'analyse des différentes classes lipidiques au niveau des feuilles jeunes et âgées a montré que le traitement par le cadmium réduit les teneurs en galactolipides et en phospholipides

Physiological and biochemical responses of Suaeda fruticosa to cadmium and copper stresses: growth, nutrient uptake, antioxidant enzymes, phytochelatin, and glutathione levels

Environmental pollution by trace metal elements (TMEs) is a serious problem worldwide, increasing in parallel with the development of human technology. The present research aimed to examine the response of halophytic species Suaeda fruticosa to oxidative stress posed by combined abiotic stresses. Plants have been grown for 1 month with an irrigation solution supplemented with 200 mM NaCl and 400 μM Cd2+ or 400 μM Cu2+. The level of glutathione (GSH), phytochelatins (PCs), and antioxidant enzyme activities [ascorbate peroxidase (APX), guaiacol peroxidase (GPX), and catalase (CAT)] as well as lipid peroxidation was studied to see the stress exerted by the TME and the level of tolerance and detoxification strategy adopted by S. fruticosa. Relative growth rate (RGR) decreased under Cd2+ stress in this species, whereas Cu2+ did not have any impact on S. fruticosa performance. Cd2+ or Cu2+ enhanced malondialdehyde, suggesting reactive oxygen species-induced disruption of membrane integrity and oxidative stress in S. fruticosa. On the other hand, the activities of the antioxidant enzymes CAT, APX, and GPX diminished and mineral nutrition was disturbed by metal stress. S. fruticosa was able to synthesize PCs in response to TME toxicity. However, data indicate that GSH levels underwent a significant decrease in roots and leaves of S. fruticosa stressed by Cd2+ or Cu2+. The GSH depletion accompanied by the increase of phytochelatin concentration suggests the involvement of GSH in the synthesis of phytochelatins.info:eu-repo/semantics/publishedVersio

Effects of Cadmium Stress on Root Tip Cells and Some Physiological Indexes in Allium Cepa Var. Agrogarum L.

Allium cepa var. agrogarum L. seedlings grown in nutrient solution were subjected to increasing concentrations of Cd2+ (0, 1, 10, 100 μM). Variation in tolerance to cadmium toxicity was studied based on chromosome aberrations, nucleoli structure and reconstruction of root tip cells, Cd accumulation and mineral metabolism, lipid peroxidation, and changes in the antioxidative defense system (SOD, CAT, POD) in leaves and roots of the seedlings. Cd induced chromosome aberrations including C-mitoses, chromosome bridges, chromosome fragments and chromosome stickiness. Cd induced the production of some particles of argyrophilic proteins scattered in the nuclei and even extruded from the nucleoli into the cytoplasm after a high Cd concentration or prolonged Cd stress, and nucleolar reconstruction was inhibited. In Cd2+-treated Allium cepa var. agrogarum plants the metal was largely restricted to the roots; very little of it was transported to aerial parts. Adding Cd2+ to the nutrient solution affected mineral metabolism. For example, at 100 μM Cd it reduced the levels of Mn, Cu and Zn in roots, bulbs and leaves. Malondialdehyde content in roots and leaves increased with treatment time and increased concentration of Cd. Antioxidant enzymes appear to play a key role in resistance to Cd under stress conditions