Physiological and biochemical responses to short-term cold stimulation of pak choi under heat stress

Abstract

Heat stress has become a global concern that will seriously affect the growth and production of crops as global warming progresses. At present, we mainly rely on traditional cultivation techniques and the assistance of horticultural facilities to address this problem, but there are many shortcomings, such as the high cost and low income. Therefore, novel approaches are needed for sustainable pak choi production under heat stress. In this work, three water treatments (15, 20, 25 °C) were imposed for one month on pak choi in a fully controlled growth chamber under heat stress. Our results indicated that the biomass of pak choi significantly increased under low-temperature water treatment compared to the control. Low-temperature water treatment inhibited the decrease in chlorophyll, soluble sugar and soluble protein, reduced the degree of membrane lipid peroxidation, and enhanced ROS scavenging enzyme activity in plants. Under low-temperature water treatment, pak choi had a higher gas exchange index, including photosynthetic rate, transpiration rate, intercellular CO2 concentration and stomatal conductance. In addition, low-temperature water treatment alleviated the adverse effects of heat stress on PS activity and electron transport.