Reactive oxygen species (ROS, partial reduction or derivatives of free radicals) are highly reactive, dangerous and can cause oxidative cell death. In addition to their role as toxic by-products of aerobic metabolism, ROS play a role in the control and regulation of biological processes such as growth, the cell cycle, programmed cell death, hormone signaling, biotic and abiotic stress reactions and development. ROS always arise in plants as a by-product of several metabolic processes that are located in different cell compartments, or as a result of the inevitable escape of electrons to oxygen from the electron transport activities of chloroplasts, mitochondria and plasma membranes. These reactive species are formed in chloroplasts, mitochondria, plasma membranes, peroxisomes, apoplasts, the endoplasmic reticulum and cell walls. The action of many non-enzymatic and enzymatic antioxidants present in tissues is required for efficient scavenging of ROS generated during various environmental stressors. The current review provides an in-depth look at the fate of ROS in plants, a beneficial role in managing stress and other irregularities. The production sites are also explained with their negative effects. In addition, the biochemical properties and sources of ROS generation, capture systems, the influence of ROS on cell biochemistry and the crosstalk of ROS with other signaling molecules/pathways are discussed.

The knowledge about the spatial distribution of soil organic carbon stock (SOCS) helps in sustainable land-use management and ecosystem functioning. No such study has been attempted in the complex topography and land use of Himalayas, which is associated with great spatial heterogeneity and uncertainties. Therefore, in this study digital soil mapping (DSM) was used to predict and evaluate the spatial distribution of SOCS using advanced geostatistical methods and a machine learning algorithm in the Himalayan region of Jammu and Kashmir, India. Eighty-three soil samples were collected across different land uses. Auxiliary variables (spectral indices and topographic parameters) derived from satellite data were used as predictors. Geostatistical methods—ordinary kriging (OK) and regression kriging (RK)—and a machine learning method—random forest (RF)—were used for assessing the spatial distribution and variability of SOCS with inter-comparison of models for their prediction performance. The best fit model validation criteria used were coefficient of determination (R2) and root mean square error (RMSE) with resulting maps validated by cross-validation. The SOCS concentration varied from 1.12 Mg/ha to 70.60 Mg/ha. The semivariogram analysis of OK and RK indicated moderate spatial dependence. RF (RMSE = 8.21) performed better than OK (RMSE = 15.60) and RK (RMSE = 17.73) while OK performed better than RK. Therefore, it may be concluded that RF provides better estimation and spatial variability of SOCS; however, further selection and choice of auxiliary variables and higher soil sampling density could improve the accuracy of RK prediction.

Earlier, the agriculture system was oriented more towards achieving higher agronomic yields than the nutritional quality of food. Green revolution significantly enhanced the crop production primarily rice, wheat and maize production was boosted to meet the energy needs of growing population. As a consequence of the predominance of cereal-based staples that are fundamentally low in micronutrients, specifically Zn and Fe, more than 2 billion people worldwide suffer from an insidious type of deficiency known as micronutrient malnutrition. Just moderate amounts of micronutrient malnutrition can affect cognitive development, reduce disease resistance and increase the risk of women dying during childbirth. The approach to micronutrient fertilization has been shown to improve the yield and nutritional content of the staples. Agronomic biofortification provides an immediate and effective method to enhance accumulation of micronutrients especially Zn and Fe in cereals. An adequate amount of plant available micronutrients is a prime requisite to ensure adequate nutrient uptake. Most of the cereals are grown in soils deficit in Zn and under reduced conditions of rice ecosystem, its availability is decreased due to formation of less soluble Zn complexes with sulphate and carbonate. The form of fertilizer used, timing and method of application is critical for the enhancement of the grain quality of Zn and Fe. The effectiveness of agronomic biofortification can be enhanced by application of synthetic chelated micronutrient fertilizers and/or organic fertilizers fortified with micronutrients in combination with NPK ensuring proper nourishment of crops with adequate nutrient supply by slow release of nutrients in soil solution. Further, the response of foliar application has shown better results than soil application. Previous studies suggest that Zn fertilization not only enhances Zn concentration in grain but also improves the overall performance of maize crop. Agronomic biofortification of crops is advantageous in terms of accessibility, rapid result, ease in application and high sustainability.