Abstract
Drought significantly threatens crop productivity and food security worldwide. However, the severity of drought is predicted to increasingly intensify in the future. To provide an antidrought strategy for farmers and breeders, the response of stomatal behavior of crops to water stress should be well studied. In this study, a lysimeter experiment was conducted to study the relationship between gas exchange parameters and grain yields of winter wheat. Light, moderate, and severe drought levels were imposed at seedling, jointing, heading, and filling stages. The results showed that crop evapotranspiration (ETc, mm) of winter wheat during the entire growing season was limited by drought imposed at any growth stage, and ETc under severe drought treatment was always the lowest. The stomatal limitation value had a significant linear correlation with the stomatal conductance (Gs, μmol mol H2O m–2 s–1) and transpiration rate (Tr, mmol H2O m–2 s–1). Light and moderate drought levels at the seedling stage did not generate irreversible physiological stress on wheat plants, while severe drought at any growth stage caused significant reduction in gas exchange parameters and grain yields. Theoretical threshold values of leaf water use efficiency (WUEl) for light, moderate, and severe drought levels were 2.62, 3.36, and 4.11 μmol mmol–1, respectively. The threshold values are useful to provide theoretical reference for achieving smart irrigation in the North China Plain.
Highlights
Drought is one of the most common factors threatening food security worldwide
Global demand for major grains such as wheat and maize is projected to increase by 70% by 2050 due to the ever-increasing population [2]. This means the agricultural sector will double the present consumption of the water resources on the planet under the current water use efficiency (WUE) level [3]
Precision irrigation according to the crop water requirement is the key to achieving high leaf water use efficiency (WUEl)
Summary
Drought is one of the most common factors threatening food security worldwide. It is predicted that the severity of drought will continue in the future under the current climate change scenarios [1]. Global demand for major grains such as wheat and maize is projected to increase by 70% by 2050 due to the ever-increasing population [2]. This means the agricultural sector will double the present consumption of the water resources on the planet under the current water use efficiency (WUE) level [3]. To mitigate the conflict between water consumption for food production and water supply for agriculture, modern irrigation technology should be developed toward smart and precision irrigation with efficient use of water [4]. Precision irrigation according to the crop water requirement is the key to achieving high leaf water use efficiency (WUEl). The main difficulty for precision irrigation lies in real-time and rapid monitoring of gas exchange parameters of crop leaves, such as the stomatal conductance (Gs, μmol mol H2O m-2 s-1) and transpiration rate (Tr, mmol H2O m-2 s-1), and WUEl [9]
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