Micronutrients’ accumulation in rice after supplemental UV-B irradiation

Abstract

UV-B-mediated effects in Oryza sativa L. are studied considering micronutrients’ accumulation and the photosynthetic performance. UV-B-irradiated rice leaves showed increasing membrane permeability and an inhibition of Fe accumulation linked to an antagonistic interaction with Mn. An increasing passive Cu uptake is also pointed, whereas Zn contents are associated with a higher root acidification capacity. In UV-B-irradiated leaves, photosynthetic pigments and the rates of the light reactions decreased significantly between the 15th and 28th day after germination. In the leaves grown after UV-B exposure, the electron transport rates coupled to photosystems II and II plus I increased significantly between the 21st and 28th day, whereas the Mehler reactions increased continuously from the 21st day onward. It is concluded that during vegetative growth the nutrient status is mostly linked to the inhibition of roots’ acidification capacity, but after UV-B exposure micronutrients’ accumulation favors this genotype recovery, shielding the photosynthetic light reactions.

Keywords:

• membrane permeability
• micronutrients
• Oryza sativa L
• photosynthesis
• root acidification capacity
• UV-B irradiation

Abbreviations:

• Chl, chlorophyll
• Cyt, cytochrome
• Cu, ZnSoD, superoxide dismutase containing Cu, Zn
• Pc, plastocyanin
• PS, photosystem
• ROS, reactive oxygen species