Drivers of Natural Variation in Water-Use Efficiency Under Fluctuating Light Are Promising Targets for Improvement in Sorghum

• DOI: 10.3389/fpls.2021.627432
• Publication Date: 2021-02-01T04:50:58Z
• Authors: Charles P. Pignon; Andrew D. B. Leakey; Stephen P. Long; Johannes Kromdijk
• Keywords: Stomatal Conductance; Water Use Efficiency; Light intensity; Photosynthetic efficiency; Specific leaf area

Improving leaf intrinsic water-use efficiency ( iWUE ), the ratio of photosynthetic CO 2 assimilation to stomatal conductance, could decrease crop freshwater consumption. has primarily been studied under steady-state light, but light in stands rapidly fluctuates. Leaf responses these fluctuations substantially affect overall plant performance. Notably, photosynthesis responds faster than stomata decreases intensity: this desynchronization results substantial loss . Traits that improve fluctuating such as movement better synchronize with photosynthesis, show significant natural diversity C 3 species. However, 4 crops have less closely investigated. Additionally, while modification or traits independent one another will theoretically a proportionate effect on , reality are inter-dependent. It is unclear how interactions between and whether some more tractable drivers Here, measurements conductance along patterning, were obtained 18 field-grown accessions sorghum. These showed highly correlated, important implications for improvement Some features, gradual appeared promising Other tradeoffs negated benefits e.g., expected benefit also displayed abrupt losses resulting lower Genetic engineering might be needed break achieve optimal trait combinations, leaves fewer, smaller stomata, sensitive changes photosynthesis. describing at steady-state, change following contributors light.