Melatonin improves the photosynthesis in

Abstract

This study investigated: (1) the effects of various concentrations of melatonin (MT) and Ca2+; and (2) the impact of crosstalk between these signal molecules on photosynthesis and salt tolerance of Dracocephalum kotschyi Boiss. Results indicated that 5mM CaCl2, as well as 100μM MT were the best concentrations for increasing shoot dry weight, leaf area, SPAD index, maximum quantum efficiency of photosystem II (Fv/Fm), and decreasing malondialdehyde content under salinity stress. The impact of MT on growth and photosynthesis was closely linked to its effect on enhancing antioxidant enzyme activities in leaves. Application of p-chlorophenylalanine, as an inhibitor of MT biosynthesis, negated the impacts of MT on the aforementioned attributes. Salinity and MT boosted cytosolic Ca2+ concentration. Exogenous MT, as well as Ca2+, enhanced tolerance index, membrane stability, leaf area, the content of chlorophyll (Chl) a, Chl b, and carotenoids (Car), Fv/Fm, and stomatal conductance under salinity stress. These impacts of MT were eliminated by applying a calmodulin antagonist, a Ca2+ chelator and a Ca2+ channel blocker. These novel findings indicate that the MT-induced effects on photosynthetic parameters and salt-evoked oxidative stress were mediated through calcium/calmodulin (Ca2+/CaM) signalling.

Mechanism of calcium in melatonin enhancement of functional substance-phenolic acid in germinated hulless barley

“…MT induced the relative genes expression involved in Ca 2+ signaling in plants. 15 Meanwhile, combined MT and Ca 2+ treatment could promote photosynthesis and salt tolerance of Dracocephalum kotschyi, 16,17 improve postharvest quality of cassava, 12 and enhances resilience against arsenic toxicity of Vicia faba. 18 The only two studies showed that MT induced the synthetic of apigenin, luteolin, and rosmarinic acid in NaClstressed Dracocephalum kotschyi 19 and astaxanthin in Haematococcus pluvialis, 20 respectively, dependent on Ca 2+ /CaM signaling.…”