Rate of photosynthetic induction in fluctuating light varies widely among genotypes of wheat. (1st March 2019)

• Record Type: Journal Article
• Authors: Salter, William T; Merchant, Andrew M; Richards, Richard A; Trethowan, Richard; Buckley, Thomas N
• Is Part Of: Journal of experimental botany. Volume 70:Number 10(2019)
• Page Start: 2787
• Page End: 2796
• Publication Date: 2019-03-01
• Subjects: Modeling -- phenotyping -- photosynthesis -- Rubisco activase -- sunfleck -- wheat; Botany -- Periodicals; Botany, Experimental -- Periodicals; Plant physiology -- Periodicals; 580
• DOI: 10.1093/jxb/erz100
• Languages: English
• ISSNs: 0022-0957

Abstract

Abstract: Crop photosynthesis and yield are limited by slow photosynthetic induction in sunflecks. We quantified variation in induction kinetics across diverse genotypes of wheat for the first time. Following a preliminary study that hinted at wide variation in induction kinetics across 58 genotypes, we grew 10 genotypes with contrasting responses in a controlled environment and quantified induction kinetics of carboxylation capacity ( V cmax ) from dynamic A versus c i curves after a shift from low to high light (from 50 µmol m –2 s –1 to 1500 µmol m –2 s –1 ), in five flag leaves per genotype. Within-genotype median time for 95% induction ( t 95 ) of V cmax varied 1.8-fold, from 5.2 min to 9.5 min. Our simulations suggest that non-instantaneous induction reduces daily net carbon gain by up to 15%, and that breeding to speed up V cmax induction in the slowest of our 10 genotypes to match that in the fastest genotype could increase daily net carbon gain by up to 3.4%, particularly for leaves in mid-canopy positions (cumulative leaf area index ≤1.5 m 2 m –2 ), those that experience predominantly short-duration sunflecks, and those with high photosynthetic capacities. Abstract : Significant variation exists in the induction time of photosynthesis following near-darkness to light transitions across wheat genotypes. Slow induction reduced daily carbon assimilation by up to 15%.