Arid Zone Research ›› 2021, Vol. 38 ›› Issue (3): 821-832.doi: 10.13866/j.azr.2021.03.24

• Plant and Plant Physiology • Previous Articles     Next Articles

Study on gas exchange parameters and water use efficiency of spring wheat leaves under different levels of water stress

CHEN Fei1(),YAN Shuang2,WANG Heling1,ZHANG Kai1,ZHAO Funian1,HUANG Xiaoyan1   

  1. 1. Institute of Arid Meteorology, China Meteorological Administration, Key Open Laboratory of Arid Climate Change and Disaster Reduction of CMA, Key Laboratory of Arid Climatic Changing and Reducing Disaster of Gansu Province, Lanzhou 730020, Gansu, China
    2. Beijing Miyun District Meteorological Bureau, Beijing 101500, China
  • Received:2020-12-21 Revised:2021-02-26 Online:2021-05-15 Published:2021-06-17

Abstract:

Leaf gas exchange parameters are the physiological basis of crop yield. Among these parameters, the photosynthetic and transpiration rates play a decisive role in leaf water use efficiency. Therefore, they are essential to research on crop drought resistance and water conservation. Potted water simulation experiments were conducted in spring wheat at Dingxi and Wuwei stations. Four group of treatments, including the control (CK), continuous drought stress (WS), moderate drought stress (40%FC), and severe drought stress (30%FC) treatments, were established to analyze the response characteristics and related characteristics of the gas exchange parameters and water use efficiency (WUEinst) of spring wheat leaves under different levels of water stress. Under continuous drought stress, the daily soil water consumption, photosynthetic rate, transpiration rate, and stomatal conductance of spring wheat all showed an initially rapid and then slow downward trend. When the stress reached moderate and severe drought, these parameters were decreased by 71% and 76%, 39% and 60%, 57% and 66%, and 60% and 77%, respectively. The extent of reduction was stomatal conductance>transpiration rate>photosynthetic rate. The intercellular CO2 concentration decreased during mild to moderate drought, and it was decreased by 33% under late moderate drought stress. Subsequently, an increasing trend was observed. WUEinst showed an upward trend during the stage from mild to moderate drought. It was increased by 41% at the late moderate drought stage, and then it decreased rapidly. Compared with CK, WUEinst increased during mild to severe drought, and it reduced after extreme drought. However, when water stress was maintained at the level of moderate or severe drought, the above indicators were similar at the same drought level under continuous drought. Additionally, the values of moderate drought were all higher than those of severe drought (P<0.05). The photosynthesis and transpiration rates were the dominant factors for each other under the mild to moderate stage of continuous drought stress, and stomatal conductance was their common dominant factor under this stress after the late moderate drought and when water stress was maintained at moderate or severe drought. WUEinst was dominantly influenced by the transpiration rate under well-watered and continuous drought stress, and it was not significantly regulated by leaf gas exchange parameters when water stress was maintained at moderate or severe drought. The research results provide a reference for informing the use of appropriate measures in different drought stages and situations.

Key words: spring wheat, water stress, photosynthetic parameters, stomatal conductance, water use efficiency