Abstract
In the context of climate change and global sustainable development goals, future wheat cultivation has to master various challenges at a time, including the rising atmospheric carbon dioxide concentration ([CO(2)]). To investigate growth and photosynthesis dynamics under the effects of ambient (~434 ppm) and elevated [CO(2)] (~622 ppm), a Free-Air CO(2) Enrichment (FACE) facility was combined with an automated phenotyping platform and an array of sensors. Ten modern winter wheat cultivars (Triticum aestivum L.) were monitored over a vegetation period using a Light-induced Fluorescence Transient (LIFT) sensor, ground-based RGB cameras and a UAV equipped with an RGB and multispectral camera. The LIFT sensor enabled a fast quantification of the photosynthetic performance by measuring the operating efficiency of Photosystem II (F(q)'/F(m)') and the kinetics of electron transport, i.e. the reoxidation rates F(r1)' and F(r2)'. Our results suggest that elevated [CO(2)] significantly increased F(q)'/F(m)' and plant height during the vegetative growth phase. As the plants transitioned to the senescence phase, a pronounced decline in F(q)'/F(m)' was observed under elevated [CO(2)]. This was also reflected in the reoxidation rates F(r1)' and F(r2)'. A large majority of the cultivars showed a decrease in the harvest index, suggesting a different resource allocation and indicating a potential plateau in yield progression under e[CO(2)]. Our results indicate that the rise in atmospheric [CO(2)] has significant effects on the cultivation of winter wheat with strong manifestation during early and late growth.