Physiological and biochemical mechanisms of brassinosteroid in improving anti-cadmium stress ability of Panax notoginseng / 中国中药杂志

In this study, the effect of brassinosteroid(BR) on the physiological and biochemical conditions of 2-year-old Panax notoginseng under the cadmium stress was investigated by the pot experiments. The results showed that cadmium treatment at 10 mg·kg~(-1) inhibited the root viability of P. notoginseng, significantly increased the content of H_2O_2 and MDA in the leaves and roots of P. noto-ginseng, caused oxidative damage of P. notoginseng, and reduced the activities of SOD and CAT. Cadmium stress reduced the chlorophyll content of P. notoginseng, increased leaf F_o, reduced F_m, F_v/F_m, and PIABS, and damaged the photosynthesis system of P. notoginseng. Cadmium treatment increased the soluble sugar content of P. notoginseng leaves and roots, inhibited the synthesis of soluble proteins, reduced the fresh weight and dry weight, and inhibited the growth of P. notoginseng. External spray application of 0.1 mg·L~(-1) BR reduced the H_2O_2 and MDA content in P. notoginseng leaves and roots under the cadmium stress, alleviated cadmium-induced oxidative damage to P. notoginseng, improved the antioxidant enzyme activity and root activity of P. notoginseng, increased the content of chlorophyll, reduced the F_o of P. notoginseng leaves, increased F_m, F_v/F_m, and PIABS, alleviated the cadmium-induced damage to the photosynthesis system, and improved the synthesis ability of soluble proteins. In summary, BR can enhance the anti-cadmium stress ability of P. notoginseng by regulating the antioxidant enzyme system and photosynthesis system of P. notoginseng under the cadmium stress. In the context of 0.1 mg·L~(-1) BR, P. notoginseng can better absorb and utilize light energy and synthesize more nutrients, which is more suitable for the growth and development of P. notoginseng.

Effects of plant growth-promoting rhizobacteria Klebsiella michiganensis TS8 and Lelliottia jeotgali MR2 on the growth and cadmium uptake of Arabidopsis thaliana under cadmium stress / 生物工程学报

In this study, the effects of two plant growth-promoting bacteria Klebsiella michiganensis TS8 and Lelliottia Jeotgali MR2 on the growth and cadmium (Cd) uptake of Arabidopsis thaliana under Cd stress were explored. A wild-type Arabidopsis thaliana was selected as the experimental plant and was planted at different Cd concentrations. MR2 and TS8 bacterial suspensions were sprayed onto the rhizospheric soil during the planting process. The initial Cd concentration of the bought soil was 14.17 mg/kg, which was used as the pot soil of the low-concentration Cd treatment group (LC). The concentration of soil Cd at high-concentration Cd treatment group (HC) were 200 mg/kg higher than that at LC group. Compared with the control group, MR2 suspension significantly promoted the growth of A. thaliana at both low and high concentrations, while TS8 strain and MR2_TS8 mixture only exhibited growth-promoting effect at high concentration. However, it was noteworthy that, TS8 suspension significantly reduced the Cd content in the underground parts of A. thaliana (60% and 59%), and significantly improved the Cd content in the aboveground parts of A. thaliana (234% and 35%) at both low and high concentrations. In addition, at low concentration, both single strain and mixed strains significantly improved the transformation from reducible Cd to acid-extractable Cd in soil, promoted Cd intake, and thereby reduced the total Cd content in soil. Therefore, the rational application of plant growth-promoting bacteria may improve crop yield and remediate Cd contamination in soil.

Study on growth and metabolites accumulation of Ganoderma lucidum mycelium by cadmium stress / 中草药

Objective: To study the effects of cadmium stress on mycelial growth and accumulation of metabolites in Ganoderma lucidum, and to explore the mechanisms affecting growth and accumulation of metabolites, and to provide evidence for controlling cadmium in the production and cultivation of G. lucidum. Methods: The mycelium of G. lucidum was cultured under the conditions of heavy metal ion cadmium concentration of 0, 0.5, 1, 4, 10, and 40 mg/L, and its biomass accumulation, intracellular ROS level, membrane oxidative damage, anti-oxidant enzyme activity, and ROS regulation related enzyme expression were analyzed. Results: When the concentration of cadmium reached 4 mg/L, the mycelial growth was inhibited. The levels of intracellular ROS, H2O2, and MDA increased significantly, increasing by 76%, 46% and 325%, respectively, and increased with the increase of cadmium concentration; The NADPH expression levels of oxidase gene (NOXA), superoxide dismutase gene (SOD1 and SOD4), and CATalase gene (CAT) were significantly up-regulated. When the cadmium concentration reached 10 mg/L, the inhibitory effect was significant. The colony growth diameter and the dry weight inhibition rate of fermentation mycelium were 26.15% and 32.78%, respectively. The total triterpenoid inhibition rate of G. lucidum was 33.7%, and the inhibition rate of total protein synthesis was 30.3%. Inhibition of polysaccharides was not significant. When the cadmium concentration reached 40 mg/L, the expression levels of Ascorbate peroxidase gene (APX) and Glutathione peroxidase gene (GPX) were significantly up-regulated. With the increase of cadmium concentration, the activities of SOD, CAT, APX, and GPX increased first and then decreased. When the concentration of cadmium reached 1 mg/L, the activity of GPX decreased and the activity of APX increased significantly. Exogenous addition of diphenyleneiodonium chloride (DPI), N-acetyl-L-cysteine (NAC) and vitamin C (VC) had significant effects on cadmium-induced G. lucidum clearance of ROS and reduction of MDA content. Conclusion: Cadmium stress causes the decrease of mycelial production and metabolite accumulation of G. lucidum, which may be due to the inhibition of GPX activity by cadmium ions, resulting in the accumulation of H2O2, causing the increase of ROS level and membrane oxidative damage, inhibiting mycelial growth and accumulation of metabolites, and regulating NOX. Up-regulation of gene expression results in an increase in anti-oxidant enzyme activity and expression to increase the clearance of reactive oxygen species. Therefore, the cadmium content should be controlled within the range of 1 mg/L during the production process.

Titanium Dioxide Nanoparticles and Sodium Nitroprusside Alleviate the Adverse Effects of Cadmium Stress on Germination and Seedling Growth of Wheat (Triticum aestivum L) / Nanopartículas de dióxido de titanio y nitroprusiato de sodio alivian los efectos adversos del estrés por cadmio en la germinación y el crecimiento de as plántulas de trigo (Triticum aestivum L) / Nanopartículas de dióxido de titânio e nitroprussiato de sódio aliviam os efeitos adversos do estresse por cádmio na germinação e no crescimento do trigo (Triticum aestivum L)

Abstract Effect of titanium dioxide nanoparticles (TiO2 NPs) (0, 500, 1 000 and 2 000 mg/L) and sodium nitroprusside (SNP) (0 and 100 μM) as nitric oxide (NO) donor, on wheat seed germination and seedling growth were investigated under cadmium (Cd) stress (0, 50 and 100 mM CdCl2). Concentration-dependent declining trends were observed in wheat germination indices upon seed exposure to CdCl2 suspensions which were more obvious under higher Cd stress. Exogenous sodium nitroprusside (SNP) and TiO2 nanoparticles (NPs) positively affected most germination indices under normal and stress conditions. In most cases, combined application of TiO2 NPs and SNP suspensions boosted stimulatory function of both compounds and moderated adverse effects of Cd treatments on wheat seed germination and seedling growth. 2 000 mg/L TiO2 + SNP (100 μM) treatment recorded the best results regarding most germination indices under lower and higher (50 and 100 mM CdCl2) Cd stress. Overall, it could be concluded that application of TiO2 NPs in combination with SNP might be a promising approach in counteracting the adverse effects of Cd stress on wheat seed germination and early growth.

Resumen Se investigó el efecto de nanopartículas de dióxido de titanio (TiO2 NPs) (0, 500, 1 000 and 2 000 mg/L) y nitroprusiato de sodio (SNP) (0 and 100 μM) como donador de óxido nítrico (NO), en la germinación de las semillas y el crecimiento de las plántulas de trigo bajo estrés por Cadmio (Cd) (0, 50 and 100 mM CdCl2). Se observaron tendencias decrecientes en los índices de germinación de las semillas de trigo expuestas a suspensiones de CdCl2. Estas tendencias fueron dependientes de la concentración, y más obvias ante alto estrés por Cd. El Nitroprusiato de Sodio exógeno (SNP) y las nanopartículas de TiO2 (NPs) afectaron positivamente la mayoría de los índices de germinación bajo condiciones normales y de estrés. En la mayoría de los casos, la aplicación combinada de suspensiones de TiO2 NPs y SNP incrementó la función estimulante de ambos componentes y moderó los efectos adversos de los tratamientos de Cd en la geminación de las semillas de trigo y el crecimiento de las plántulas. Con el tratamiento de 2000 mg/L TiO2 + SNP (100 μM) se registraron los mejores resultados en cuanto a los índices de germinación sometidos a bajo y alto estrés por Cd (50 and 100 mM CdCl2). En general, podría concluirse que la aplicación de TiO2 NPs en combinación con SNP podría ser una aproximación promisoria para contrarrestar los efectos adversos del estrés por Cd en la germinación de las semillas de trigo y en su crecimiento temprano.

Resumo Foram investigados os efeitos de nanopartículas de dióxido de titânio (TiO2 NPs) (0, 500, 1000 e 2000 mg/L) e nitroprussiato de sódio (SNP) (0 e 100 pM) como donadoras de óxido nítrico (NO) na germinação de sementes e no crescimento de plántulas de trigo sob estresse por cádmio (Cd) (0, 50 e 100 mM CdCl2). Se observaram tendências decrescentes nos índices de germinação de sementes de trigo expostas a suspensões de CdCl2. Essas tendências foram dependentes da concentração, sendo mais evidentes frente ao alto estresse por Cd. O nitroprussiato de sódio (SNP) e as nanopartículas de TiO2 (NPs) afetaram positivamente a maioria dos índices de germinação sob condições normais e de estresse. Na maioria dos casos, a aplicação combinada de suspensões de TiO2 NPs e SNP aumentou a função estimulante de ambos componentes e moderou os efeitos adversos dos tratamentos de Cd na germinação de semestres de trigo e no crescimento das plántulas. Com o tratamento de 2 000 mg/L TiO2 + SNP (100 μM) se registraram os melhores resultados em quanto aos índices de germinação submetidos a baixo e alto estresse por Cd (50 e 100 mM CdCl2). De modo geral, se pode concluir que a aplicação de TiO2 NPs em combinação com SNP poderia ser uma aproximação promissora para combater os efeitos adversos do estresse por Cd na germinação de sementes de trigo e no seu crescimento inicial.

Effects of cadmium stress on growth and physiological characteristics of Panax ginseng / 中草药

Objective: To investigate the effects of cadmium (Cd) stress on the growth and physiological characteristics of Panax ginseng (ginseng). Methods: Two-year old ginseng was cultivated in barrels in phytotrone with different concentration of Cd (0, 0.3, 1.0, 2.0, and 4.0 mg/kg) soil for a whole growth period. In red fruit stage, the contents of biomass and SPAD, the activities of anti-oxidant enzymes, and contents of malondialdehyde (MDA) were determined and analyzed. Results: With Cd concentration increasing, the relative growth rate of ginseng expressed a slowly decreasing trend, and showed negative linear correlations with Cd stress level (P stem > root. Conclusion: Ginseng has an adaptability to the contaminated soil with Cd (≤1.0 mg/kg), and at this time ginseng can enhance the activity of anti-oxidant enzyme and other physiological and biochemical responses to eliminate reactive oxygen species, maintain stability of the cell membrane, alleviate the harm from the stress of Cd; Though with Cd (>1 mg/kg), the contents of MDA could increase significantly, and the oxidative damage of ginseng is very serious. The growth of plants is affected, resulting in a decline in ginseng biomass.

Mitogen-activated protein kinase genes of Artemisia annua and their expression analysis under Cadmium stress / 中国中药杂志

In order to study Artemisia annua under cadmium stress, whether there are corresponding MAPK genes involved in transduction of the cadmium signal. 17 AaMAPK genes, named AaMAPK1-AaMAPK17 repectively, were finally obtained by using Trinity method for de novo assembly of transcripts from SRA database and BLAST search against AtMAPK genes and determing conserved domain using a series of bioinformatics tools. There exist 16 MAPK genes contained T[D/E]Y conserved domains among the obtained genes. The expressions of these genes were analyzed by Real-time PCR under cadmium stress. The results showed that the expressions level of AaMAPK3 and AaMAPK10 were down-regulated and MAPK7, MAPK9 and MAPK12 were up-regulated. These indicated that there exist corresponding MAPK genes involved in transduction of the cadmium signal.

Cadmium induced changes on proline, antioxidant enzymes, nitrate and nitrite reductases in Arachis hypogaea L.

The groundnut, Arachis hypogaea seedlings, when grown in pot cultures for 10–25 days at 25, 50, 100 "M CdCl2 , showed a marked decline in growth compared to control. Similar trend was observed for nitrate reductase (NR) and nitrite reductase (NiR) activities whereas proline, peroxidase (POD) and catalase (CAT) showed increasing trend when observed on the 10th day of the experiment. Changes have occurred in the physiological and biochemical activities which are observed even at low Cd levels (25 "M). At 100 "M concentration, with increase in experimental days, Cd has imposed drastic decrease in leaf and stem respectively, where nitrate reductase has varied from 20.87 – 79.41 and 29.11 – 72.91 % and nitrite reductase 21.66 – 79.41 and 43.58 – 75.92% respectively. Contrastingly Cd treated plant tissues showed an increase in proline 111.2 – 159.87 % (percentage changes) and 131.23 – 212.16 % for leaves and stems respectively, In addition cadmium caused significant changes in the activity of antioxidative enzymes, peroxidase 48.12 – 72.19 % in leaf and 37.71 – 75.25 % in stem and catalase 64.86 – 143.92 % in leaf and 129.13 – 214.74 % in stem as compared to control. The study concludes that the activities of NR, NiR, proline, POD, CAT are inhibited suggesting that Arachis hypogaea seedlings are under Cd stress affecting their growth.