Plasticity in stomatal behaviour across a gradient of water supply is consistent among field-grown maize inbred lines with varying stomatal patterning.
Risheng Ding, Jiayang Xie, Dustin Mayfield-Jones, Yanqun Zhang, Shaozhong Kang, Andrew D B Leakey
Author Information
Risheng Ding: Center for Agricultural Water Research in China, China Agricultural University, Beijing, China. ORCID
Jiayang Xie: Department of Crop Sciences, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA.
Dustin Mayfield-Jones: Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA.
Yanqun Zhang: State Key Laboratory of Simulation and Regulation of Water Cycle in River Basin, Department of Irrigation and Drainage, China Institute of Water Resources and Hydropower Research, Beijing, China.
Shaozhong Kang: Center for Agricultural Water Research in China, China Agricultural University, Beijing, China.
Andrew D B Leakey: Department of Crop Sciences, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA. ORCID
Stomata regulate leaf CO assimilation (A) and water loss. The Ball-Berry and Medlyn models predict stomatal conductance (g ) with a slope parameter (m or g ) that reflects the sensitivity of g to A, atmospheric CO and humidity, and is inversely related to water use efficiency (WUE). This study addressed knowledge gaps about what the values of m and g are in C crops under field conditions, as well as how they vary among genotypes and with drought stress. Four inbred maize genotypes were unexpectedly consistent in how m and g decreased as water supply decreased. This was despite genotypic variation in stomatal patterning, A and g . m and g were strongly correlated with soil water content, moderately correlated with predawn leaf water potential (Ψ ), but not correlated with midday leaf water potential (Ψ ). This implied that m and g respond to long-term water supply more than short-term drought stress. The conserved nature of m and g across anatomically diverse genotypes and water supplies suggests there is flexibility in structure-function relationships underpinning WUE. This evidence can guide the simulation of maize g across a range of water supply in the primary maize growing region and inform efforts to improve WUE.
