Photoprotective pigments, like those involved in the xanthophyll cycle, help plants avoid oxidative damage caused by excess radiation. This study aims to characterize a spectrum of strategies used to cope with light stress by a diverse group of prairie plants at Cedar Creek Ecosystem Science Reserve (East Bethel, MN). We find that concentrations of photosynthetic and photoprotective pigments are highly correlated with one another and with other physiological traits across species and over time, and tend to be phylogenetically conserved. During a period of water limitation, plots dominated by species with constitutively low pigment concentrations showed a greater decline in mean reflectance and photochemical reflectance index, a reflectance-based indicator of photoprotective physiology, possibly due to alterations in canopy structure. Our findings suggest two contrasting strategies for withstanding light stress: (1) Using photoprotective pigments to dissipate excess energy, and (2) altering canopy structure to minimize absorbance of excess radiation.
Bibliographical noteFunding Information:
Received 1 July 2017, accepted 6 November 2017, published as online-first 10 January 2018. +Corresponding authors; phone: (734) 502-2817, (612) 624-6337; e-mail: email@example.com, e-mail: firstname.lastname@example.org Abbreviations: Chl – total chlorophyll (a + b) concentration; CWM – community-weighted mean; DPS – xanthophyll de-epoxidation state; ETR – electron transport rate; fAPAR – fraction of absorbed photosynthetically active radiation; Fv/Fm – maximal quantum yield of PSII photochemistry; LUE – light-use efficiency; ML – maximum likelihood; NDVI – normalized difference vegetation index; NIR – near-infrared light; NPQ – nonphotochemical quenching; PC – principal component; PCA – principal component analysis; PRI – photochemical reflectance index; V+A+Z – xanthophyll pool size; VIS – visible light; WUEi – intrinsic water-use efficiency; ρn – reflectance at wavelength n; ΦPSII – effective quantum yield of PSII photochemistry. Acknowledgements: We would like to thank staff at Cedar Creek Ecosystem Science Reserve, including Kally Worm and Troy Mielke. Funding to support this study was provided by a grant from the National Science Foundation (NSF) and National Aeronautics and Space Administraton (NASA) through the Dimensions of Biodiversity program (DEB-1342872) to J. Cavender-Bares, R. Montgomery, and J. Gamon. Additional support was provided by an NSF Long-Term Ecological Research grant to Cedar Creek (DEB-1234162) and an NSF Graduate Research Fellowship to S. Kothari under Grant No. 00039202. Jon Anderson determined percent cover of species in the field, Austin Pieper assisted with HPLC and pigment extraction, and Anna K. Schweiger and Cathleen Nguyen aided in interpreting the pigment concentrations from HPLC. All members of the Cavender-Bares Lab and Cristy Portales provided useful feedback on the research and manuscript. © The Author(s). This article is published with open access at link.springer.com
- light-use efficiency
- trait covariance
- water-use efficiency