Coupling the environmental impacts of reactive nitrogen losses and yield responses of staple crops in China.

Cropland reactive nitrogen losses (Nr) are of the greatest challenges facing sustainable agricultural intensification to meet the increases in food demand. The environmental impacts of Nr losses and their yield responses to the mitigation strategies were not completely evaluated. We assessed the environmental impacts of Nr losses in China and coupled the efficiency of mitigation actions with yield responses. Datasets about Nr losses in China were collected, converted into potentials of acidification (AP), global warming (GWP), and aquatic eutrophication (AEP), and analyzed by a meta-analysis program. Results showed that producing 1 Mg of rice grains had the highest AP (153 kg acid equiv.), while wheat had the highest GWP and AEP (74 kg CO2 equiv. and 0.37 kg PO4 equiv., respectively). Using the conventional rates (averagely, 200, 230, and 215 kg N ha-1) of urea as a surface application to produce 131.4, 257.2, and 212.1 Tg of wheat, maize, and rice resulted in 17-33 Tg, 7-10 Tg, and 6-87 Gg of AP, GWP, and AEP, respectively. For their balanced effect on reducing AP, GWP, and AEP while maximizing yields, inhibitors, and subsurface application could be set as the best mitigation strategies in wheat production. Inhibitors usage and biochar are strongly recommended strategies for sustainable production of maize. None of the investigated strategies had a balanced effect on rice yield and the environment, thus new mitigation technologies should be developed.

Integrative application of licorice root extract or lipoic acid with fulvic acid improves wheat production and defenses under salt stress conditions.

Although different plant extracts and plant growth regulators are used as biostimulants to support plants grown under salt stress conditions, little information is available regarding the use of licorice root extract (LRE) or lipoic acid (LA) as biostimulants. Studies on the application of LRE or LA in combination with fulvic acid (FA) as natural biostimulants have not been performed. Therefore, in this study, two pot experiments were conducted to evaluate the potential effects of LRE (5 g L-1) or LA (0.1 mM) supplemented as a foliar spray in combination with FA (0.2 mg kg-1 soil) on osmoprotectants and antioxidants, growth characteristics, photosynthetic pigments, nutrient uptake, and yield as well as on the anatomical features of the stems and leaves of wheat plants irrigated with three levels of saline water (0.70, 7.8, and 14.6 dSm-1). Moderate (7.8 dSm-1) and high (14.6 dSm-1) levels of salinity caused a significant (p ≤ 0.05) increase in the activities of SOD, APX CAT, POX, and GR as well as in electrolyte leakage, malondialdehyde level, and reactive oxygen species (O2‒ and H2O2) levels compared to those in controls (plants irrigated with tap water). However, the leaf relative water content, membrane stability index, NPK uptake, leaf area, plant height, spike length, straw yield, grain yield, and protein content of wheat grains significantly (p ≤ 0.05) decreased. Addition of LRE or LA and/or HA to wheat plants under saline stress significantly (p ≤ 0.05) enhanced their morphological and physio-biochemical characteristics in parallel with increases in the activities of enzymatic antioxidants. Salinity stress altered (p ≤ 0.05) wheat stem and leaf structures; however, treatment with LRE + FA significantly improved these negative effects. These findings indicate that FA + LRE treatment significantly improved the antioxidant defense system of the plants, thereby reducing ROS levels and increasing wheat growth and production under saline conditions.

Glutathione S-transferase gene polymorphism: Relation to cardiac iron overload in Egyptian patients with Beta Thalassemia Major.

OBJECTIVES: Estimating the prevalence of glutathione S-transferase gene polymorphism (GSTM1) null genotype among patients with beta thalassemia major (ß-TM) in relation to myocardial status assessed by tissue Doppler and cardiac siderosis assessed by cardiac magnetic resonance imaging (MRI) T2*. METHODS: Hundred patients with ß-TM and 100 healthy controls were enrolled. Complete blood count (CBC), mean serum ferritin and GSTM1 genotyping, echocardiography, tissue Doppler, and cardiac MRI T2* were done. RESULTS: Serum ferritin ranged from 1200 to 8000 ng/ml, and mean T2* value was 27.10 ± 11.20 ms. Of patients, 68 (68%) had no cardiac siderosis, while 24 (24%) with mild to moderate, and 8 (8%) with sever cardiac siderosis. T2* values were not correlated with serum ferritin (r = -0.09, P = 0.50). GSTM1 null genotype was prevalent in 46% of patients and 40% of controls (P = 0.69). Patients with null genotype had significantly shorter T2* (P = 0.001), higher left ventricular end-diastolic diameter (P = 0.002), and shorter ejection time (P = 0.005) with no significant relation to serum ferritin (P = 0.122). GSTM1 null genotype was the only predictor for cardiac iron overload (P = 0.002). DISCUSSION: Serum ferritin concentrations have been shown to correlate poorly with all stages of cardiac dysfunction. Low cardiac MRI T2* values occur in patients with ß-TM despite good chelation therapy, suggesting a possible role of genetic factors in cardiac siderosis. CONCLUSION: GSTM1 null genotype is significantly associated with cardiac iron overload independent of serum ferritin in Egyptian patients with ß-TM.