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Field analysis of photoprotection in co‐occurring cool climate C 3 and C 4 grasses
Author(s) -
Shay PhilipEdouard,
Kubien David S
Publication year - 2013
Publication title -
physiologia plantarum
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.351
H-Index - 146
eISSN - 1399-3054
pISSN - 0031-9317
DOI - 10.1111/j.1399-3054.2012.01662.x
Subject(s) - photoprotection , xanthophyll , photoinhibition , chlorophyll fluorescence , botany , growing season , photosynthesis , biology , chemistry , photosystem ii
C 4 photosynthesis is particularly successful at high light intensities and high temperatures, but is relatively rare when the average growing season temperature is less than about 15°C. We tested the hypothesis that rapidly reversible photoprotection enables some C 4 species to tolerate cool climates, by focusing on two questions: (1) Do chlorophyll fluorescence responses differ seasonally between co‐occurring C 3 and C 4 grasses in the field? (2) Does xanthophyll‐mediated photoprotection differ between the two pathways? Spartina pectinata ( C 4 ) and Calamogrostis canadensis ( C 3 ) were sampled in a herbaceous fresh‐water meadow in New Brunswick, Canada (45°N 66°W). Non‐photochemical thermal energy dissipation (Φ NPQ ) and the epoxidation state of the xanthophyll cycle ( EPS ) were used as indicators of photoprotection. We observed no differential susceptibility to chronic photoinhibition (i.e. photodamage) between the C 3 and C 4 species, except potentially during spring emergence. On average, C. canadensis showed higher levels of protective dynamic photoinhibition throughout the growing season, but S. pectinata had greater Φ NPQ and lower EPS during seasonal and daily temperature minima. The low Rubisco capacity of C 4 species is a potential limiting factor to C 4 success at high latitudes, but our findings suggest that it is unlikely via a photoinhibitory feedback mechanism.