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ARS Home » Plains Area » Fort Collins, Colorado » Center for Agricultural Resources Research » Water Management and Systems Research » Research » Publications at this Location » Publication #334957
Title: Embolized stems recover overnight in Zea Mays: the role of soil water, root pressure, and nighttime transpiration

Author
item Gleason, Sean
item Wiggans, Dustin
item Bliss, Clayton
item YOUNG, JASON - Cantigny Gardens
item Cooper, Mitchell
item Willi, Kathryn
item Comas, Louise

Submitted to: Frontiers in Plant Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/11/2017
Publication Date: 4/28/2017
Citation: Gleason, S.M., Wiggans, D.R., Bliss, C.A., Young, J.S., Cooper, M.S., Willi, K.R., Comas, L.H. 2017. Embolized stems recover overnight in Zea Mays: the role of soil water, root pressure, and nighttime transpiration. Frontiers in Plant Science. 8:662.

Interpretive Summary: It is not currently well-understood if maize’s ability to transport water (e.g., inside stems) declines during the day, nor if damage to the water transport tissues can be recovered overnight if plants are given sufficient water. To answer these questions we designed a greenhouse experiment whereby two genetically dissimilar maize genotypes were subjected to a level of water stress commonly experience in the field. We then measured the decline in the capacity of maize stems to transport water, as well as the overnight recovery following three different watering treatments: 1) fully watering pots until they were completely saturated, 2) partially watering plants, and 3) not supplying any additional water to plants. Fully watering pots resulted in nearly complete recovery of maize stems by morning (76% of maximal). Partial watering resulted in partial recovery of stems (51.7% of maximal), whereas not watering resulted in no recovery. Recovery of the ability of stems to transport water was facilitated by the generation of root pressure and low rates of water loss from the canopy at night.

Technical Abstract: It is not currently well-understood how much xylem conductance is lost in maize plants during the day, if conductance is recovered during the night, or what soil water conditions are required for recovery to take place. To answer these questions we designed a greenhouse experiment whereby two genetically dissimilar maize genotypes were subjected to a level of water stress commonly experience in the field ('xylem ~ -2 MPa). We then measured the loss of stem conductance associated with this level of stress, as well as the overnight recovery following three re-watering treatments: 'soil ~ 0 MPa, 'soil ~ -0.40 MPa, and 'soil ~ -1.70 MPa. Midday leaf water potentials of -1.98 MPa resulted in stem-specific conductivity (KS) values that were 31.5% of maximal (i.e., 68% loss). Returning soils to field capacity ('soil ~ 0 MPa) overnight allowed for the significant recovery of KS (76% of maximal), whereas partial watering ('soil ~ -0.40 MPa) resulted KS values that were 51.7% of maximal values, whereas not watering resulted in no recovery (35.4% of maximal; 'soil ~ -1.7 MPa). Recovery of KS was facilitated by the generation of root pressure and low rates of nighttime transpiration.