Excess light leads to photoinhibition, invisible damage to the photosynthetic apparatus. Photoinhibition is a common process and the damage is readily repaired by the plant. At too much light, however, the damage cannot be fully repaired and visual leaf damage occurs.
Photoinhibition can be measured as a lowering of the maximum photosynthesis efficiency (Fv/Fm). In the project 'Grip on Light' Anthurium 'Pink Champion' Bromelia Vriesea 'Miranda' were exposed to high light to study the relation between photoinhibition and leaf damage.
In a climate chamber the plants were exposed for 5 days to diffuse light (1100 μmol PAR.m-2.s-1, Philips daylight lamp) with leaf temperatures not exceeding 35°C. At light doses up to 24.5 mol.m-2.day-1 photoinhibition was observed right after exposure, but no visual leaf damage was observed. The photoinhibition was repaired within a few days. These results show that potanthurium and bromelia tolerate very high light levels if the leaf temperature is kept normal. Possibly diffuse daylight can be utilized even better than the 25% shortening of cultivation cycle reported in 2012.
'Grip on Light' is financed by the programs Biosolar Cells and Kas als Energiebron of the Ministry of Economic Affairs and the Product Board and by Ludvig Svensson and Guardian.