Leaf Photosynthetic and Photoprotective Acclimation in the Ultraviolet‐A1 and Blue Light Regions Follow a Continuous, Shallow Gradient

Le résumé fourni par la source

ABSTRACT Although blue light is known to produce leaves with high photosynthetic capacity, the role of the blue‐adjacent UV‐A1 (350–400 nm) in driving leaf photosynthetic acclimation is less studied. Tomato plants were grown under hybrid red and blue (RB; 95/5 μmol m−2 s−1), as well as four treatments in which RB was supplemented with 50 μmol m−2 s−1 peaking at 365, 385, 410 and 450 nm, respectively. Acclimation to 365–450 nm led to a shallow gradient increase in trait values (i.e., photosynthetic capacity, pigmentation and dry mass content) as the peak wavelength increased. Furthermore, both UV‐A1 and blue light grown leaves showed efficient photoprotection under high light intensity. When treated plants were transferred to fluctuating light for 5 days, leaves from all treatments showed increases in photosynthetic capacity, which were strongest in RB, followed by additional UV‐A1 treatments; RB grown leaves showed reductions in maximum quantum yield of photosystem II, while UV‐A1 grown leaves showed increases. We conclude that both UV‐A1 and blue light effectively trigger photosynthetic and photoprotective acclimation, the extent of acclimation becoming stronger the longer the peak wavelength is. Acclimatory responses to UV‐A1 and blue light are thus not distinct from one another, but follow a continuous gradient.

Ce résumé expose les affirmations des auteurs. BNTIC ne l’interprète pas comme une validation indépendante des résultats.