High-Resolution Three-Dimensional Structural Data Quantify the Impact of Photoinhibition on Long-Term Carbon Gain in Wheat Canopies in the Field  . Issue 2 (17th August 2015)

• Record Type: Journal Article
• Authors: Burgess, Alexandra J.; Retkute, Renata; Pound, Michael P.; Foulkes, John; Preston, Simon P.; Jensen, Oliver E.; Pridmore, Tony P.; Murchie, Erik H.
• Is Part Of: Plant physiology. Volume 169:Issue 2(2015)
• Page Start: 1192
• Page End: 1204
• Publication Date: 2015-08-17
• Subjects: Plant physiology -- Periodicals; Botany -- Periodicals; Periodicals; Electronic journals; 571.2
• DOI: 10.1104/pp.15.00722
• Languages: English
• ISSNs: 0032-0889

Abstract

Abstract : A digital reconstruction method models the effect of photoinhibition on daily canopy photosynthesis in three contrasting wheat canopies. Abstract: Photoinhibition reduces photosynthetic productivity; however, it is difficult to quantify accurately in complex canopies partly because of a lack of high-resolution structural data on plant canopy architecture, which determines complex fluctuations of light in space and time. Here, we evaluate the effects of photoinhibition on long-term carbon gain (over 1 d) in three different wheat ( Triticum aestivum ) lines, which are architecturally diverse. We use a unique method for accurate digital three-dimensional reconstruction of canopies growing in the field. The reconstruction method captures unique architectural differences between lines, such as leaf angle, curvature, and leaf density, thus providing a sensitive method of evaluating the productivity of actual canopy structures that previously were difficult or impossible to obtain. We show that complex data on light distribution can be automatically obtained without conventional manual measurements. We use a mathematical model of photosynthesis parameterized by field data consisting of chlorophyll fluorescence, light response curves of carbon dioxide assimilation, and manual confirmation of canopy architecture and light attenuation. Model simulations show that photoinhibition alone can result in substantial reduction in carbon gain, but this is highly dependent on exact canopy architecture and the diurnal dynamics of photoinhibition. The use of such highly realistic canopy reconstructions also allows us to conclude that even a moderate change in leaf angle in upper layers of the wheat canopy led to a large increase in the number of leaves in a severely light-limited state.