Sulfur is one of the inorganic elements used by plants to develop and produce phytoalexin to resist certain diseases. This study reported a method for preparing a material for plant disease resistance. Sulfur nanoparticles (SNPs) stabilized in the chitosan-Cu2+ (CS-Cu2+) complex were synthesized by hydrolysis of Na2S2O3 in an acidic medium. The obtained SNPs/CS-Cu2+ complex consisting of 0.32% S, 4% CS, and 0.7% Cu (w/v), contained SNPs with an average size of ~28 nm as measured by transmission electron microscopy images. The X-ray diffraction pattern of the SNPs/CSCu2+ complex showed that SNPs had orthorhombic crystal structures. Interaction between SNPs and the CS-Cu2+ complex was also investigated by ultraviolet-visible. Results in vitro nematicidal effect of materials against Meloidogyne incognita showed that SNPs/CS-Cu2+ complex was more effective in killing second-stage juveniles (J2) nematodes and inhibiting egg hatching than that of CS and CS-Cu2+ complex. The values of LC50 in killing J2 nematodes and EC50 in inhibiting egg hatching of SNPs/CS-Cu2+ complex were 75 and 51 mg/l, respectively. These values were lower than those of CS and the CS-Cu2+ complex. The test results on the nematicidal effect against M. incognita on coffee pots showed that the SNPs/CS-Cu2+ complex was 100% effective at a concentration of 150 mg/l. Therefore, the SNPs/CS-Cu2+ complex could be considered as a biochemical material with potential for agricultural applications to control root-knot nematodes.

Chitin (degree of deacetylation ~18.13%, average viscosity molecular weight ~79.128 g/mol), prepared from molted whiteleg shrimp shells, was used to synthesize a chitin selenoester-zinc (ChSe-Zn) complex via a heterogeneous reaction with ZnSO4 and SeO2 in an acid medium. The resulting complex was characterized by Ultraviolet-visible, X- ray diffraction, and Fourier-transform infrared spectroscopy. Dietary supplementation with the ChSe-Zn complex (25.1 g Zn/kg and 239 mg Se/kg) at ~42 mg Zn/kg and 0.4 mg Se/kg in whiteleg shrimp (Litopenaeus vannamei) significantly enhanced growth and antioxidant capacity compared with the control group, and showed comparable effects to the diet containing zinc proteinate and selenomethionine at the same Zn and Se concentrations. These results highlight the potential of the ChSe-Zn complex as a feed additive to enhance shrimp growth and antioxidant capacity, while utilizing molted shrimp shell waste and reducing reliance on other organic Zn and Se sources.

The pyrolysis of coconut husk (CH) impregnated with Mg(OH) ₂ at 400 °C produced MgO nanoparticles/coconut husk biochar (MgO NPs/CHB) containing 1.29% MgO (w/w). The biochar yield from Mg(OH) ₂ -treated biomass reached 51.47%, which was higher than that obtained from untreated CH (41.23%). The morphology and particle size of MgO NPs were characterized by scanning and transmission electron microscopy, with average sizes of about 24.4 nm and 28.4 nm, respectively. The structural and physicochemical properties of the material were analyzed using x-ray diffraction, Fourier transform infrared spectroscopy, thermogravimetric analysis, and N ₂ adsorption-desorption analysis. Seed priming with MgO NPs/CHB at a concentration of 100 mg MgO/L improved the ability of rice seedlings to cope with salt-induced stress, as indicated by increased chlorophyll content, plant height, and root length after 7 days of salt treatment under 75 mM NaCl. In addition, MgO NPs/CHB priming alleviated salt-induced stress in rice seedlings, as evidenced by reduced activities of antioxidant enzymes compared to the salt-stressed control, such as superoxide dismutase and catalase, lower malondialdehyde content, and an increased K ⁺ /Na ⁺ ratio in leaves compared to the non-primed salt-stressed control.

Nano ZnO/chitosan oligosaccharide (ZnO/COS) and nano ZnO/chitosan oligosaccharide-iodine complex (ZnO/COS-I2) prepared in this study are new materials consisting of ZnO nanoparticles (12.3 - 15.0 nm) dispersed in COS and COS-I2 solutions. Both ZnO/COS and ZnO/COS-I2 nanomaterials have the ability to resist Pantoea stewartii (P. stewartii) causes jackfruit bronzing bacterium. The COS with a low molecular weight (Mw) of 3,320 g/mol has the main advantage that is completely soluble in both acidic and alkaline mediums to pH 9. The characterizations of materials nanomaterials were determined by gel permeation chromatography (GPC), nuclear magnetic resonance (1H-NMR), transmission electron microscopy (TEM), and X-ray diffraction (XRD). The results of the in vitro test against P. stewartii of ZnO/COS-I2 nanomaterial showed that the antibacterial efficacy is 100% at 500 ppm of active ingredient concentration. The studied results also confirmed that nano ZnO/COS-I2 nanomaterial has the ability to inhibit bacteria higher than that nano ZnO/COS nanomaterial. Therefore, the ZnO/COS-I2 nanomaterial has great potential to use as an effective agent to control the serious damage jackfruit bronzing bacterium and has no specific treatment.