Reduced blade greenness indicates impaired nitrogen metabolism in spring wheat transitioning to reproductive development under a 6 h-6 h light-dark cycle

One strategy for optimizing light conditions in space missions is tailoring the photoperiod to shorten the growth cycle, increasing the annual number of cycles.
As spring wheat (Triticum aestivum L.) is a long day plant, it requires a short night to induce flowering.
In an experiment conducted under a short dark period in a 6 h-6 h light-dark cycle, SPAD values, used as a proxy for chlorophyll content, were measured and combined with analysis of nitrogen and nitrate content.
Strikingly low SPAD values were measured in leaves that appeared around the onset of stem elongation, resulting in nitrate accumulation.
During the transition to reproductive development, source-sink relationships faced significant pressure, impairing leaf nitrogen metabolism and chlorophyll production under a 6 h-6 h light-dark cycle.
We therefore recommend to align changes in light-dark cycles with specific growth stages to support plant physiology and optimize yield.

X International Symposium on Light in Horticulture

H. Clauw, H. Van de Put, A. Sghaier, T. Kerkaert, K. Steppe

SPAD, spring wheat, Triticum aestivum L., nitrogen metabolism, source-sink relationships, growth chamber

https://doi.org/10.17660/ActaHortic.2025.1423.8