Role of Ferrous Sulfate (FeSO4) in Resistance to Cadmium Stress in Two Rice (Oryza sativa L.) Genotypes.

The impact of heavy metal, i.e., cadmium (Cd), on the growth, photosynthetic pigments, gas exchange characteristics, oxidative stress biomarkers, and antioxidants machinery (enzymatic and non-enzymatic antioxidants), ions uptake, organic acids exudation, and ultra-structure of membranous bounded organelles of two rice (Oryza sativa L.) genotypes (Shan 63 and Lu 9803) were investigated with and without the exogenous application of ferrous sulfate (FeSO4). Two O. sativa genotypes were grown under different levels of CdCl2 [0 (no Cd), 50 and 100 µM] and then treated with exogenously supplemented ferrous sulfate (FeSO4) [0 (no Fe), 50 and 100 µM] for 21 days. The results revealed that Cd stress significantly (p < 0.05) affected plant growth and biomass, photosynthetic pigments, gas exchange characteristics, affected antioxidant machinery, sugar contents, and ions uptake/accumulation, and destroy the ultra-structure of many membranous bounded organelles. The findings also showed that Cd toxicity induces oxidative stress biomarkers, i.e., malondialdehyde (MDA) contents, hydrogen peroxide (H2O2) initiation, and electrolyte leakage (%), which was also manifested by increasing the enzymatic antioxidants, i.e., superoxidase dismutase (SOD), peroxidase (POD), catalase (CAT) and ascorbate peroxidase (APX) and non-enzymatic antioxidant compounds (phenolics, flavonoids, ascorbic acid, and anthocyanin) and organic acids exudation pattern in both O. sativa genotypes. At the same time, the results also elucidated that the O. sativa genotypes Lu 9803 are more tolerant to Cd stress than Shan 63. Although, results also illustrated that the exogenous application of ferrous sulfate (FeSO4) also decreased Cd toxicity in both O. sativa genotypes by increasing antioxidant capacity and thus improved the plant growth and biomass, photosynthetic pigments, gas exchange characteristics, and decrease oxidative stress in the roots and shoots of O. sativa genotypes. Here, we conclude that the exogenous supplementation of FeSO4 under short-term exposure of Cd stress significantly improved plant growth and biomass, photosynthetic pigments, gas exchange characteristics, regulate antioxidant defense system, and essential nutrients uptake and maintained the ultra-structure of membranous bounded organelles in O. sativa genotypes.

Molybdenum Supply Alleviates the Cadmium Toxicity in Fragrant Rice by Modulating Oxidative Stress and Antioxidant Gene Expression.

Increasing evidence shows that cadmium (Cd) toxicity causes severe perturbations on growth performance, physio-biochemical and molecular processes in crop plants. Molybdenum (Mo), an essential trace element, plays key roles in oxidative stress tolerance of higher plants. Hence, the present study has been conducted to investigate the possible role of Mo in alleviating Cd-induced inhibitions in two fragrant rice cultivars namely Guixiangzhan (GXZ) and Meixiangzhan-2 (MXZ-2). The results revealed that Mo application enhanced the plant dry biomass by 73.24% in GXZ and 58.09% in MXZ-2 under Cd stress conditions, suggesting that Mo supplementation alleviated Cd-induced toxicity effects in fragrant rice. The enhanced Cd-tolerance in fragrant rice plants prompted by Mo application could be ascribed to its ability to regulate Cd uptake and reduce Cd-induced oxidative stress as evident by lower hydrogen peroxide levels, electrolyte leakage and malondialdehyde contents in Cd-stressed plants. The ameliorative role of Mo against Cd-toxicity also reflected through its protection to the photosynthetic pigments, proline and soluble protein. Mo also induced antioxidant defense systems via maintaining higher contents of glutathione and ascorbate as well as enhancing the ROS-detoxifying enzymes such as catalase, peroxidase, superoxide dismutase and ascorbate peroxidase activities and up-regulating transcript abundance in both fragrant rice cultivars under Cd stress. Conclusively, Mo-mediated modulation of Cd toxicity in fragrant rice was through restricting Cd uptake, maintaining photosynthetic performance and alleviating oxidative damages via the strong anti-oxidative defense systems; however, GXZ cultivar is comparatively more Cd tolerant and Mo-efficient as evident from the less growth inhibition and biomass reduction as well as enhanced Mo-induced Cd stress tolerance and less oxidative damage than MXZ-2 fragrant rice cultivar.

Molybdenum-induced effects on leaf ultra-structure and rhizosphere phosphorus transformation in Triticum aestivum L.

Soil phosphorus (P) occurs in pools of lower availability due to soil P fixation and therefore, it is a key constrain to crop production. Long term molybdenum-induced effects in wheat and rhizosphere/non-rhizosphere soil P dynamics have not yet been investigated. Here, a long term field experiment was conducted to explore these effects in wheat consisting of two treatments i.e. with molybdenum (+Mo) and without molybdenum (-Mo). The results revealed that molybdenum (Mo) supply increased plant biomass, grain yield, P uptake, preserved the configuration of chloroplast, stomata, and mesophyll tissue cells, suggesting the complementary effects of Mo on wheat yield and P accumulation. During the periods of vegetative growth, soil organic carbon, organic matter, and microbial biomass P were higher and tended to decrease in rhizosphere soil at maturity stage. In +Mo treatment, the most available P fractions [H2O-Pi (16.2-22.9 mg/kg and 4.24-7.57 mg/kg) and NaHCO3-Pi (130-149 mg/kg and 77.2-88 mg/kg)] were significantly increased in rhizosphere and non-rhizosphere soils, respectively. In addition, the +Mo treatment significantly increased the acid phosphatase activity and the expression of phoN/phoC, aphA, olpA/lppC gene transcripts in rhizosphere soil compared to -Mo. Our research findings suggested that Mo application has increased P availability not only through biochemical and chemical changes in rhizosphere but also through P assimilation and induced effects in the leaf ultra-structures. So, it might be a strategy of long term Mo fertilizer supply to overcome the P scarcity in plants and rhizosphere soil.

Soil phosphorus transformation characteristics in response to molybdenum supply in leguminous crops.

Phosphorus (P) is one of the most restrictive essential elements to crop growth and development due to less availability in the soil system. Previous studies have reported the synergistic effects between molybdenum (Mo) and P fertilizer on P uptake in various crops. However, an induced long term effect of Mo on soil P dynamics in the rhizosphere and non-rhizosphere has not been reported yet in leguminous crops. In this study, a long term field experiment was conducted to explore the P transformation characteristics and bioavailability in Mo-deficient (-Mo) and Mo-enriched (+Mo) soil under leguminous (broad bean-soybean) cropping system. The results indicated that long-term Mo application increased the plant dry matter accumulation (14.23%-35.27%, for broad bean; 24.40%-37.46%, for soybean) from March-September. In rhizosphere soil, the percent decrease in pH (8.10%) under +Mo treatment of the soybean crop was recorded more during September as compared to broad bean crop. Under Mo supply, H2O-Pi fraction increased up to 28.53% and 43.67% while for NaHCO3-Pi this increase was up to 5.61% and 11.98%, respectively in the rhizosphere soil of broad bean and soybean, whereas, residual-P exhibited the highest proportion of P fractions. Moreover, compared with -Mo, +Mo treatments significantly increased the soil acid phosphatase (broad bean = 17.43 µmol/d/g; soybean = 28.60 µmol/d/g), alkaline phosphatase (broad bean = 3.34 µmol/d/g; soybean 6.35 µmol/d/g) and phytase enzymes activities (broad bean = 2.45 µmol/min/g; soybean = 5.91 µmol/min/g), transcript abundance of phoN/phoC genes and microbial biomass P (MBP) in rhizosphere soil. In crux, the findings of this study suggest that long term Mo application enhanced P bioavailability through increased available P, MBP, P related enzymes activities and their genes expressions which may represent a strategy of Mo to encounter P deficiencies in the soil system.

Effect of Citric Acid on Growth, Ecophysiology, Chloroplast Ultrastructure, and Phytoremediation Potential of Jute (Corchorus capsularis L.) Seedlings Exposed to Copper Stress.

Soil and water contamination from heavy metals and metalloids is one of the most discussed and caused adverse effects on food safety and marketability, crop growth due to phytotoxicity, and environmental health of soil organisms. A hydroponic investigation was executed to evaluate the influence of citric acid (CA) on copper (Cu) phytoextraction potential of jute (Corchorus capsularis L.). Three-weeks-old seedlings of C. capsularis were exposed to different Cu concentrations (0, 50, and 100 µM) with or without the application of CA (2 mM) in a nutrient growth medium. The results revealed that exposure of various levels of Cu by 50 and 100 µM significantly (p < 0.05) reduced plant growth, biomass, chlorophyll contents, gaseous exchange attributes, and damaged ultra-structure of chloroplast in C. capsularis seedlings. Furthermore, Cu toxicity also enhanced the production of malondialdehyde (MDA) which indicated the Cu-induced oxidative damage in the leaves of C. capsularis seedlings. Increasing the level of Cu in the nutrient solution significantly increased Cu uptake by the roots and shoots of C. capsularis seedlings. The application of CA into the nutrient medium significantly alleviated Cu phytotoxicity effects on C. capsularis seedlings as seen by plant growth and biomass, chlorophyll contents, gaseous exchange attributes, and ultra-structure of chloroplast. Moreover, CA supplementation also alleviated Cu-induced oxidative stress by reducing the contents of MDA. In addition, application of CA is helpful in increasing phytoremediation potential of the plant by increasing Cu concentration in the roots and shoots of the plants which is manifested by increasing the values of bioaccumulation (BAF) and translocation factors (TF) also. These observations depicted that application of CA could be a useful approach to assist Cu phytoextraction and stress tolerance against Cu in C. capsularis seedlings grown in Cu contaminated sites.

Influence of phosphorus on copper phytoextraction via modulating cellular organelles in two jute (Corchorus capsularis L.) varieties grown in a copper mining soil of Hubei Province, China.

Soil in mining areas is typically highly contaminated with heavy metals and lack essential nutrients for plants. Phosphorus reduces oxidative stress, improves plant growth, composition, and cellular structure, as well as facilitates the phytoremediation potential of fibrous crop plant species. In this study, we investigated two jute (Corchorus capsularis) varieties HongTieGuXuan and GuBaChangJia cultivated in copper (Cu)-contaminated soil (2221 mg kg-1), under different applications of phosphorus (0, 30, 60, and 120 kg ha-1) at both anatomical and physiological levels. At the same Cu concentration, the tolerance index of HongTieGuXuan was higher than that of GuBaChangJia, indicating that HongTieGuXuan may be more tolerant to Cu stress. Although the normal concentration of P (60 kg ha-1) in the soil improved plant growth, biomass, chlorophyll content, fibre yield and quality, and gaseous exchange attributes. However, high concentration of P (120 kg ha-1) was toxic to both jute varieties affected morphological and physiological attributes of the plants under same level of Cu. Moreover, Cu toxicity increased the oxidative stress in the leaves of both jute varieties was overcome by the activities of antioxidant enzymes. Furthermore, the high concentration of Cu altered the ultrastructure of chloroplasts, plastoglobuli, mitochondria, and many other cellular organelles in both jute varieties. Thus, phytoextraction of Cu by both jute varieties increased with the increase in P application in the Cu-contaminated soil. This suggests that P application enhanced the phytoremediation potential jute plants and can be cultivated as fibrous crop in Cu-contaminated sites.

Acupuncture/Electroacupuncture as an Alternative in Current Opioid Crisis / 中国结合医学杂志

Opioid drugs are the first line of defense in severe pain but the adverse effects associated with opioids are considered as a serious issue worldwide. Acupuncture/electroacupuncture is a type of Chinese medicine therapy which is an effective analgesic therapy, well documented in animals and human studies. Electroacupuncture stimulation could release endogenous opioid peptides causing analgesia in a variety of pain models. It can be used as an alternative therapy to control the opioid crisis.

Molybdenum-induced effects on photosynthetic efficacy of winter wheat (Triticum aestivum L.) under different nitrogen sources are associated with nitrogen assimilation.

Different nitrogen (N) sources have been reported to significantly affect the photosynthesis (Pn) and its attributes. However, molybdenum (Mo) induced effects on photosynthetic efficacy of winter wheat under different N sources have not been investigated. A hydroponic study was carried out comprising of two winter wheat cultivars '97003' and '97014' as Mo-efficient and Mo-inefficient, respectively to underpin the effects of Mo supply (0 and 1 µM) on photosynthetic efficacy of winter wheat under different N sources (NO3̶, NH4NO3 or NH4+). The results revealed that Mo-induced increases in dry weight, gas exchange parameters, chlorophyll contents, NR activities, NO3̶ assimilation, total N contents and transcripts of TaNR and TaNRT1.1 genes under different N sources followed the trend of NH4NO3 > NO3̶ > NH4+, suggesting that Mo has more complementary effects to nitrate nutrition than sole ammonium. Interestingly, under Mo-deprivation environments, cultivar '97003' recorded more pronounced alterations in Mo-dependent parameters than '97014' cultivar. Moreover, Mo application significantly improved the chlorophyll contents and chloroplast configuration in all N sources showing that Mo has a key role in chlorophyll biosynthesis and chloroplast integrity. The results also highlighted that Mo-induced enhancements in total N contents and photosynthetic characteristics followed the same order as NH4NO3 > NO3- > NH4+, suggesting that Mo might affect Pn through N metabolism. In crux, our study findings imply that Mo supply increased Pn not only through chlorophyll synthesis and chloroplast configuration but also by N uptake and assimilation which may represent a strategy of Mo fertilizer to strengthen the photosynthetic machinery.

Molybdenum-Induced Effects on Nitrogen Metabolism Enzymes and Elemental Profile of Winter Wheat (Triticum aestivum L.) Under Different Nitrogen Sources.

Different nitrogen (N) sources have been reported to significantly affect the activities and expressions of N metabolism enzymes and mineral elements concentrations in crop plants. However, molybdenum-induced effects in winter wheat cultivars have still not been investigated under different N sources. Here, a hydroponic study was carried out to investigate these effects on two winter wheat cultivars ('97003' and '97014') as Mo-efficient and Mo-inefficient, respectively, under different N sources (NO3-, NH4NO3, and NH4+). The results revealed that the activities of nitrate reductase (NR) and nitrite reductase (NiR) followed the order of NH4NO3 > NO3- > NH4+ sources, while glutamine synthetase (GS) and glutamate synthase (GOGAT) followed the order of NH4+ > NH4NO3 > NO3- in both the wheat cultivars. However, Mo-induced effects in the activities and expressions of N metabolism enzymes under different N sources followed the order of NH4NO3 > NO3- > NH4+ sources, indicating that Mo has more complementary effects towards nitrate nutrition than the sole ammonium source in winter wheat. Interestingly, under -Mo-deprived conditions, cultivar '97003' recorded more pronounced alterations in Mo-dependent parameters than '97014' cultivar. Moreover, Mo application increased the proteins, amino acids, ammonium, and nitrite contents while concomitantly decreasing the nitrate contents in the same order of NH4NO3 > NO3- > NH4+ sources that coincides with the Mo-induced N enzymes activities and expressions. The findings of the present study indicated that Mo plays a key role in regulating the N metabolism enzymes and assimilatory products under all the three N sources; however, the extent of complementation exists in the order of NH4NO3 > NO3- > NH4+ sources in winter wheat. In addition, it was revealed that mineral elements profiles were mainly affected by different N sources, while Mo application generally had no significant effects on the mineral elements contents in the winter wheat leaves under different N sources.

Can Selenium and Molybdenum Restrain Cadmium Toxicity to Pollen Grains in Brassica napus?

Cadmium (Cd) is highly toxic, even at very low concentrations, to both animals and plants. Pollen is extremely sensitive to heavy metal pollutants; however, less attention has been paid to the protection of this vital part under heavy metal stress. A pot experiment was designed to investigate the effect of foliar application of Se (1 mg/L) and Mo (0.3 mg/L) either alone or in combination on their absorption, translocation, and their impact on Cd uptake and its further distribution in Brassica napus, as well as the impact of these fertilizers on the pollen grains morphology, viability, and germination rate in B. napus under Cd stress. Foliar application of either Se or Mo could counteract Cd toxicity and increase the plant biomass, while combined application of Se and Mo solutions on B. napus has no significant promotional effect on plant root and stem, but reduces the seeds' weight by 10⁻11%. Se and Mo have decreased the accumulated Cd in seeds by 6.8% and 9.7%, respectively. Microscopic studies, SEM, and pollen viability tests demonstrated that pollen grains could be negatively affected by Cd, thus disturbing the plant fertility. Se and Mo foliar application could reduce the toxic symptoms in pollen grains when the one or the other was sprayed alone on plants. In an in vitro pollen germination test, 500 µM Cd stress could strongly inhibit the pollen germination rate to less than 2.5%, however, when Se (10 µM) or Mo (1.0 µM) was added to the germination medium, the rate increased, reaching 66.2% and 39.4%, respectively. At the molecular level, Se and Mo could greatly affect the expression levels of some genes related to Cd uptake by roots (IRT1), Cd transport (HMA2 and HMA4), Cd sequestration in plant vacuoles (HMA3), and the final Cd distribution in plant tissue at the physiological level (PCS1).