Electron Transport Through Photosystem II Is Not Limited By A Wide Range of Water Deficit Conditions In Field‐Grown Gossypium hirsutum. Issue 1 (26th November 2013)

• Record Type: Journal Article
• Authors: Snider, J. L.; Collins, G. D.; Whitaker, J.; Perry, C. D.; Chastain, D. R.
• Is Part Of: Journal of agronomy and crop science. Volume 200:Issue 1(2014:Feb.)
• Page Start: 77
• Page End: 82
• Publication Date: 2013-11-26
• Subjects: Agronomy -- Periodicals; Crop science -- Periodicals; 630.5
• DOI: 10.1111/jac.12044
• Languages: English
• ISSNs: 0931-2250

Abstract

<abstract abstract-type="main" id="jac12044-abs-0001"> <title>Abstract</title> <p>Despite exhaustive literature describing drought stress effects on photosynthesis in <italic>Gossypium hirsutum</italic>, the sensitivity of photosynthetic electron flow to water deficit is heavily debated. To address this, <italic>G. hirsutum</italic> plants were grown at a field site near Camilla, GA under contrasting irrigation regimes, and pre‐dawn water potential (Ψ<sub>PD</sub>), stomatal conductance (g<sub>s</sub>), net photosynthesis (P<sub>N</sub>), actual quantum yield of photosystem II (Φ<sub>PSII</sub>) and electron transport rate (ETR) were measured at multiple times during the 2012 growing season. Ψ<sub>PD</sub> values ranged from −0.3 to −1.1 MPa. Stomatal conductance exhibited a strong (r<sup>2</sup> = 0.697), sigmoidal response to Ψ<sub>PD</sub>, where g<sub>s</sub> was ≤0.1 mol m<sup>−2</sup> s<sup>−1</sup> at Ψ<sub>PD</sub> values ≤ −0.86 MPa. Neither Φ<sub>PSII</sub> (r<sup>2</sup> = 0.015) nor ETR (r<sup>2</sup> = 0.010) was affected by Ψ<sub>PD</sub>, despite exceptionally low Ψ<sub>PD</sub> values (−1.1 MPa) causing a 71.7 % decline in P<sub>N</sub> relative to values predicted for well‐watered <italic>G. hirsutum</italic> leaves at Ψ<sub>PD</sub> = −0.3 MPa. Further, P<sub>N</sub> was strongly influenced by g<sub>s</sub>, whereas ETR and Φ<sub>PSII</sub> were not. We conclude that photosynthetic electron flow through photosystem II is insensitive to water deficit in field‐grown <italic>G. hirsutum</italic>.</p> </abstract>