Zinc deficiency is one of the most widespread nutritional problems, affecting nearly one-third of the world population. In addition, it is known that zinc deficiency not only reduces crop yield but also its quality. The effect of different methods of zinc application on the growth, yield, and quality of safflower seeds under regular irrigation and interruption of irrigation from flowering to harvest (82 and 80 DAS in the first and second years, respectively) was evaluated. Zinc sulfate was applied in both soil and foliar methods. The zinc sulfate treatments include no zinc sulfate, soil application of 20, 40, and 60 kg ha(-1) at the planting stage; spraying 2.5, 5, and 7.5 g L-1 in the rosette stage; and spraying 2.5, 5, and 7.5 g L-1 in the flowering stage. The end-season drought caused a decrease in the chlorophyll index, leaf area index, relative water content, plant height, yield components, biological yield, seed yield, harvest index, seed oil content, oil harvest index, and seed element content compared to regular irrigation. The decrease in yield occurred with a decrease in the capitol number and diameter, seed number per capitol, and 1000-seed weight. The severity of the damage of the end-season drought stress in the second year was higher than in the first year due to the higher temperatures and the decrease in the rainfall. In both years, the application of zinc sulfate in different ways had an increasing effect on the studied traits in both normal and stress conditions. The application of zinc sulfate reduced the negative effects of unfavorable environmental conditions and improved the yield and nitrogen, phosphorus, potassium, zinc, and iron element content in the seed. In both application methods of zinc sulfate, the increment in the zinc sulfate concentration decreased the seed phosphorus content. However, the phosphorous content was more than that of the treatment of non-zinc application. The application of zinc increased the biological, seed, and oil yield of the treated plants, but the seed and oil yield were more affected. This effect was shown in the seed and oil harvest index increment. Under regular irrigation, higher concentrations of zinc sulfate enhanced plant performance, but under stress conditions, medium and lower concentrations were more effective. The highest 1000-seed weight and potassium and zinc content were obtained by spraying zinc sulfate at 5 g L-1 in the flowering stage under normal irrigation conditions. A comparison of the two methods of applying zinc sulfate showed that foliar spraying was more effective than soil application in improving the seed yield. The soil application is more effective on biological yield than seed yield.

The remediation of soil contaminated with cadmium (Cd) and arsenic (As) has consistently been a complex issue. Foliar application of jasmonic acid (JA) could be a promising agronomic practice for reducing heavy metal accumulations. However, the combined reduction effects and mechanisms of Cd and As in rice through foliar JA application have not been fully explored. In this study, a pot experiment was conducted to investigate rice yield, Cd and As accumulations and translocations, photosynthesis, and ROS-scavenging attributes in Huanghuazhan (HHZ) and Huarun No.2 (HR). The results revealed that 1 mu M JA treatment significantly decreased the concentrations of Cd (by 34.6% in HHZ and 38.3% in HR) and As (by 30.8% in HHZ and 40.8% in HR) in the grains, and increased the percentage of filled-grain and 1000-grain weight in HHZ. The structural equation model (SEM) indicated that grain Cd was directly and positively affected by panicle Cd and leaf sheath Cd, while grain As was directly and positively affected by panicle As, leaf blade As and leaf sheath As. JA application enhanced the net photosynthetic rate and chlorophyll content (both a and b). Additionally, it scavenged levels of H2O2 and O2.-, reduced lipid peroxidation damage by promoting the activities of antioxidant enzymes and altering the cellular redox status in the flag leaves of rice. Overall, these results suggest that foliar JA application of could be an effective strategy for preventing Cd and As accumulations in rice grains in paddy soils with low to medium contamination risks.