Elevated [CO2]-induced changes prevented peanut plants from photosynthetic acclimation to water deficit

Authors: Echevarria Laza, Haydee; Baker, Jeffrey; Yates, Charles; Mahan, James; BUROW, MARK - Texas Tech University; PUPPALA, NAVEEN - New Mexico State University; Gitz, Dennis; Emendack, Yves; Layland, Nancy; RITCHIE, GLEN - Texas Tech University; Chen, Junping; Rowland, Diane; Payton, Paxton

Submitted to: Agricultural and Forest Meteorology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/4/2021
Publication Date: 8/16/2021
Citation: Echevarria Laza, H.J., Baker, J.T., Yates, C.E., Mahan, J.R., Burow, M., Puppala, N., Gitz, D.C., Emendack, Y., Layland, N.L., Ritchie, G., Chen, J., Rowland, D., Payton, P.R. 2021. Elevated [CO2]-induced changes prevented peanut plants from photosynthetic acclimation to water deficit. Agricultural and Forest Meteorology. 308-309. https://doi.org/10.1016/j.agrformet.2021.108599.
DOI: https://doi.org/10.1016/j.agrformet.2021.108599

Interpretive Summary: Food demand is expected to increase through 2100; thus, understanding crop performance in future climates is crucial for developing resilient crop cultivars. ARS scientists evaluated the interactive effects of elevated [CO2], drought, and heat on peanut productivity, and gas exchange capacity using field-based growth chambers during two cropping seasons. We observed that peanut plants did not acclimate to soil-water deficit under [CO2] enrichment. However, rising [CO2] counteracted the negative effect of drought on physiological plasticity, leading to more Carbon(C) assimilation, and yield. Unlike C, water exchange varied across developmental stages and soil-water availabilities. Our findings challenge the assumption that [CO2] always reduce the stomatal conductance, questioning the relevance of stomata in enriched [CO2] environments. Our results show that peanut production is most likely to increase in future climates. We highlight that non-stomatal traits might be more relevant than stomatal factors and should be further investigated for selection of resilient cultivars. We suggest including our results into current global models for improving C cycling and crop performance predictions.

Technical Abstract: Understanding how plants adjust to dynamic environments is key for predicting their performance in challenging climates. Yet the acclimation of crop species to combined stresses is not well understood. Peanut (Arachis hypogaea L.) is a C3 legume responsive to CO2 with physiological acclimation capabilities to soil water deficit. We investigated whether elevated [CO2] could modify such responses by examining the leaf-photosynthetic acclimation to the interactive effects of elevated [CO2] (650 ppm) and soil-water deficit with further impact on productivity, and gas exchange capacity using field-based growth chambers during two cropping seasons. In this study, we did not observe leaf photosynthetic acclimation to elevated [CO2]. Further, rising [CO2] prevented plants from photosynthetic acclimation to soil-water deficit and counteracted the reduced photosynthetic plasticity induced by soil-water deficit. We observed that stomatal conductance (gs) and transpiration (E) responses to elevated [CO2] varied across developmental stages and soil-water availabilities. Our findings challenge the assumption of elevated CO2-induced gs and E down-regulation; indicating that it is not a lifetime universal response. We highlight that non-stomatal traits might be more relevant than stomatal factors and should be further investigated for selection of resilient cultivars. We suggest including our results into current global models for improving C cycling and crop performance predictions.