Greater productivity under drought among Zea mays genotypes is linked to plant hydraulic strategies

Authors: Comas, Louise; Gleason, Sean; DROBNITCH, SARAH - Colorado State University; CHINTAMANANI, SATYA - Syngenta; BENSEN, ROBERT - Syngenta

Submitted to: Annals of Botany
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/13/2025
Publication Date: 8/16/2026
Citation: Comas, L.H., Gleason, S.M., Drobnitch, S.T., Chintamanani, S., Bensen, R. 2026. Greater productivity under drought among Zea mays genotypes is linked to plant hydraulic strategies. Annals of Botany. 136(7):1537-1545. https://doi.org/10.1093/aob/mcaf177.
DOI: https://doi.org/10.1093/aob/mcaf177

Interpretive Summary: Many plant mechanisms respond concurrently when plants are under drought stress. Identifying key plant mechanisms driving productivity under limited water, thus, has been challenging. We examined traits across six maize genotypes varying in productivity under limited water. Data were collected on shoot hydraulic conductivity, stomatal conductance, root flow, gas exchange, and fluorescence. Genotypes with high yield under limited water in the field had high capacity for whole shoot hydraulic conductivity in the greenhouse and peak diurnal stomatal conductance in the field. Interestingly, genotypes having high yield under limited water in the field also had high root flow in drought recovery in the greenhouse, which may be a mechanism for embolism repair or turgor recovery to aide plants in resuming carbon fixation following drought. Genotypes with high grain yield under limited water in the field tended to have greater capacity for maximum photosynthesis, transpiration, and stomatal conductance in the greenhouse. However, these same genotypes down-regulated photosynthesis more quickly and tended to have more sensitive stomatal closure when maintained under prolonged water limitation in the greenhouse. Because both photosynthesis and stomatal conductance declined similarly among genotypes grown with limited water, instantaneous water use efficiency determined under limited water in the greenhouse was similar among genotypes and did not show any relationship with grain yield under limited water in the field. In summary, evidence here suggests that a successful strategy for maize under limited water is to maintain the maximum gas exchange allowed by their hydraulic capacity, risk but repair embolism, and close stomata quickly in the middle part of the day under sustained drought. Ultimately, fully successful strategies for maintaining crop productivity under drought should hinge on the frequency and amount of soil water availability under limited water conditions.

Technical Abstract: Many plant mechanisms respond concurrently when plants are under drought stress. Identifying key plant mechanisms driving productivity under limited water, thus, has been challenging. We examined traits across six maize genotypes varying in productivity under limited water. Data were collected on shoot hydraulic conductivity, diurnal stomatal conductance, root flow (as a proxy for root pressure), gas exchange, and fluorescence. Genotypes with high yield under limited water in the field had high capacity for whole shoot hydraulic conductivity in the greenhouse and peak diurnal stomatal conductance in the field. Interestingly, genotypes having high yield under limited water in the field also had high root flow during drought recovery in the greenhouse, which may be a mechanism for embolism repair or turgor recovery to aide plants in resuming carbon fixation following drought. Genotypes with high grain yield under limited water in the field tended to have greater capacity for maximum photosynthesis, transpiration, and stomatal conductance in the greenhouse. However, these same genotypes down-regulated photosynthesis more quickly and tended to have more sensitive stomatal closure when maintained under prolonged water limitation in the greenhouse. Because both photosynthesis and stomatal conductance declined similarly among genotypes grown with limited water, instantaneous water use efficiency determined under limited water in the greenhouse was similar among genotypes and did not show any relationship with grain yield under limited water in the field. In summary, evidence here suggests that a successful strategy for maize under limited water is to maintain the maximum gas exchange allowed by their hydraulic capacity, risk but repair embolism, and close stomata quickly in the middle part of the day under sustained drought. Ultimately, fully successful strategies for maintaining crop productivity under drought should hinge on the frequency and amount of soil water availability under limited water conditions.