Effects of mineral fertilization (NPK) on combined high temperature and ozone damage in rice

Abstract

Background Increasing concern has recently been highlighted regarding crop damage due to extreme weather events caused by global warming and the increased production of ground-level ozone gas (O₃). Several studies have investigated rice growth in response to fertilization conditions under various environmental stress conditions; however, studies on growth development in response to fertilization conditions under combined high-temperature/ozone treatment conditions are scarce. Therefore, this study was conducted to analyze the growth and physiological development of rice under combined high temperature and ozone treatment conditions and to reveal the damage-mitigation effects of NPK fertilization treatments. Results The results showed that the combined high-temperature/ozone treatment appeared to promote phenological development by increasing leaf age compared to normal conditions, but had a negative effect on quantitative growth by decreasing plant height and dry weight. The effects of this combined high-temperature/ozone treatment on growth were alleviated in K-2 (K2) treatments and worsened in N-2 (N2) treatments. Visible damage symptoms in rice leaves also tended to be alleviated by the K treatment. Meanwhile to physiologically analyse the effectiveness of K2 treatment in alleviating growth injury, antioxidant and abscisic acid (ABA)-related gene expression and stomatal conductance were analysed. As in the case of growth, the results showed that K2 treatment could alleviate the damage. Conclusion This study confirmed the possibility of reducing combined high-temperature/ozone damage by fertilization control and is expected to be used as basic data for related studies.