The Response Mechanism and Threshold of Spring Wheat to Rapid Drought
Fei Chen,
Heling Wang,
Funian Zhao,
Runyuan Wang,
Yue Qi,
Kai Zhang,
Hong Zhao,
Guoying Tang,
Yang Yang
Affiliations
Fei Chen
Key Laboratory of Arid Climatic Change and Disaster Reduction of Gansu Province/Key Laboratory of Arid Climate Change and Disaster Reduction of China Meteorological Administration (CMA), Lanzhou Institute of Arid Meteorology, CMA, Lanzhou 730020, China
Heling Wang
Key Laboratory of Arid Climatic Change and Disaster Reduction of Gansu Province/Key Laboratory of Arid Climate Change and Disaster Reduction of China Meteorological Administration (CMA), Lanzhou Institute of Arid Meteorology, CMA, Lanzhou 730020, China
Funian Zhao
Key Laboratory of Arid Climatic Change and Disaster Reduction of Gansu Province/Key Laboratory of Arid Climate Change and Disaster Reduction of China Meteorological Administration (CMA), Lanzhou Institute of Arid Meteorology, CMA, Lanzhou 730020, China
Runyuan Wang
Key Laboratory of Arid Climatic Change and Disaster Reduction of Gansu Province/Key Laboratory of Arid Climate Change and Disaster Reduction of China Meteorological Administration (CMA), Lanzhou Institute of Arid Meteorology, CMA, Lanzhou 730020, China
Yue Qi
Key Laboratory of Arid Climatic Change and Disaster Reduction of Gansu Province/Key Laboratory of Arid Climate Change and Disaster Reduction of China Meteorological Administration (CMA), Lanzhou Institute of Arid Meteorology, CMA, Lanzhou 730020, China
Kai Zhang
Key Laboratory of Arid Climatic Change and Disaster Reduction of Gansu Province/Key Laboratory of Arid Climate Change and Disaster Reduction of China Meteorological Administration (CMA), Lanzhou Institute of Arid Meteorology, CMA, Lanzhou 730020, China
Hong Zhao
Key Laboratory of Arid Climatic Change and Disaster Reduction of Gansu Province/Key Laboratory of Arid Climate Change and Disaster Reduction of China Meteorological Administration (CMA), Lanzhou Institute of Arid Meteorology, CMA, Lanzhou 730020, China
Guoying Tang
Key Laboratory of Arid Climatic Change and Disaster Reduction of Gansu Province/Key Laboratory of Arid Climate Change and Disaster Reduction of China Meteorological Administration (CMA), Lanzhou Institute of Arid Meteorology, CMA, Lanzhou 730020, China
Yang Yang
Key Laboratory of Arid Climatic Change and Disaster Reduction of Gansu Province/Key Laboratory of Arid Climate Change and Disaster Reduction of China Meteorological Administration (CMA), Lanzhou Institute of Arid Meteorology, CMA, Lanzhou 730020, China
In order to deeply understand the effect mechanism of rapid drought stress on the physiological and biochemical properties of crop leaves and determine drought thresholds, the potted spring wheat under two water treatments, adequate water supply and continuous drought stress, was researched. In the early stage of drought, the parameters of leaves decreased in the order of stomatal conductance (gs), intercellular CO2 concentration (Ci), maximum electron transfer rate (Jmax), mesophyll conductance (gm), photosynthetic rate (Pn,) leaf water content (LWC), triose phosphate utilization rate (TPU), transpiration rate (Tr), and maximum carboxylation rate (Vcmax). Photosynthesis was dominated by stomatal limitation and also limited by carboxylation and mesophyll limitation. The carboxylation limitation was mainly caused by the reduction of electron transport capacity. In the late stage of drought, stomatal limitation first decreased, and then mesophyll limitation decreased. During extreme drought, carboxylation limitation also decreased. With the decrease of relative soil moisture (RSM), except for Ci, which first decreased and then increased, other physicochemical parameters of leaves all showed an S-shaped, decreasing trend. Mild and severe drought thresholds were determined to be 56.6% and 43.6% of the RSM, respectively, according to the curve’s inflection point, corresponding to 16.6% and about 52.2% of the average initial decrease amplitude among all parameters. This will provide a reference for monitoring as well as an early warning of rapid drought in spring wheat.
