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Evaluating the Mechanisms of Photosynthetic Inhibition under Growth‐Limiting, Early‐Season Water Deficit Stress in Cotton
Author(s) -
Meeks Calvin D.,
Snider John L.,
Babb-Hartman Megan E.,
Barnes Tony L.
Publication year - 2019
Publication title -
crop science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.76
H-Index - 147
eISSN - 1435-0653
pISSN - 0011-183X
DOI - 10.2135/cropsci2018.07.0432
Subject(s) - photosynthesis , biology , stomatal conductance , growing season , transpiration , dry matter , limiting , agronomy , drought stress , water use efficiency , horticulture , botany , mechanical engineering , engineering
The current study evaluated the possibility that growth‐limiting, early‐season drought stress sufficient to decrease net photosynthesis ( A N ) would be associated with declines in stomatal conductance (g s ) and ATP content, regardless of stress level. Studies were conducted in greenhouse facilities in Athens and Tifton, GA, and imposed different early‐season drought durations to generate a range of early‐season water‐deficit stress conditions. The early‐season drought durations imposed decreased A N to values ranging from 20 to 60% of the levels observed in well‐watered plants. Where declines in A N were observed, g s and photosynthetic electron transport rate (ETR) declined substantially, indicating some level of metabolic and possibly diffusional limitation to photosynthesis. The ATP content was unaffected or actually increased in response to photosynthesis‐limiting drought in both years of the study, suggesting that ATP‐induced limitations to photosynthesis are minimal over a broad range of A N –limiting, early‐season drought stress conditions in cotton ( Gossypium hirsutum L.). All drought durations limited leaf, stem, reproductive, and total dry matter production. Declines in dry matter under mild stress were primarily associated decreased leaf area production, whereas decreased A N was likely an important contributor under more severely stressed treatments. Photosynthetic declines under growth‐limiting, early‐season drought do not appear to be associated with reduced ATP production, as suggested in other plant species.