Melatonin and resveratrol reverse the toxic effect of high boron (B) and modulate biochemical parameters in pepper plants (Capsicum annuum L.)

The objectives of this research were to test a possible involvement of melatonin (MEL) and resveratrol (RES) in restoring growth and to control boron (B) toxicity in peppers. The plants were subjected to four different nutrient solution treatments as following: 1) half-strength Hoagland's nutrient solution (Control), 2) half-strength Hoagland's nutrient solution-F100 mu M B (100 mu MB), 3) half-strength Hoag land's nutrient solution+100 mu M boron+100 mu Mresveratrol (100 mu MRES), and 4) half-strength Hoag land's nutrient solution+100 mu M B+1 Mmelatonin (1 mu M MEL). Pepper plants subjected to B excess (100 mu M) for 68 days (d) exhibited visible B toxicity symptoms, reduced rate of photosynthesis (Pn) and reduced dry weight (DW), while their leaf and fruit had the greatest increase of B concentration. The reduction of photosynthesis was restored, the reduction of DW was prevented, while the B leaf and fruit accumulation was moderated with the application of both 100 mu Mresveratrol (RES) and 1 mu Mmelatonin (MEL). Moreover, plants exposed to MEL and/or RES displayed no visible B toxicity symptoms. The present study revealed a novel role of MEL and/or RES in the adaptation of pepper plants to B excess based on plant growth, physiological and biochemical criteria. (C) 2017 Elsevier Masson SAS. All rights reserved.