Influence of the magnesium content in apple leaves photosynthetic capacity
Fruit trees photosynthesis is determined by abiotic factors affecting crop productivity. The aim of this study was to evaluate the influence of magnesium nutritional status and exposure to solar radiation in the photosynthetic capacity of leaves of Malus domestica 'Cripp's Pink'. A two-factor experiment was conducted: high (+Mg) and low (-Mg) foliar Mg content (0.26 and 0.19%, respectively) in leaves were exposed to high (HR) and low (LR) solar radiation (1600 and 600 μmol m-2 s-1, respectively). Chlorophyll concentration, maximum quantum yield of photosystem-II (Fv/Fm) and net photosynthesis rate was determined in leaves. HR and LR -Mg leaves had 11.5 and 1.8% less chlorophyll concentration respectively than HR and LR +Mg leaves; no effects were observed in chlorophyll concentration by exposure. Fv/Fm was affected by sun exposition but not by Mg content. In HR leaves Fv/Fm was 5-6% lower than in LR leaves. Photosynthesis was affected by magnesium content when leaves where exposed to high solar radiation. Maximum net photosynthesis in HR +Mg leaves was 20.0 μmol m-2 s-1, while in HR -Mg was 11.1 μmol m-2 s-1. Net photosynthesis in LR leaves was not affected by Mg content. These results show that apple leaves photosynthetic capacity could be affected by lower Mg content when exposed to high solar radiation.
Blackhall, V., Curetti, M., Orioli, G.A. and Colavita, G.M. (2018). Influence of the magnesium content in apple leaves photosynthetic capacity. Acta Hortic. 1217, 151-158
high light stress, chlorophyll a fluorescence transient, apple, magnesium