The levels of melatonin and its metabolites in conditioned corn (Zea mays L.) and cucumber (Cucumis sativus L.) seeds during storage

Abstract

The efficiency of pre-sowing conditioning/ priming methods used to apply melatonin into seeds was verified: osmopriming in the case of dicot Cucumis sativus and hydropriming of monocot Zea mays seeds. Both priming techniques were selected experimentally as optimal for the studied plant species. Four different seed variants were compared: control non-treated ones, and seeds conditioned with water or with 50 or 500 lM melatonin water solutions. The HPLC-MS quantitative and qualitative analyses were used to determine the content of melatonin and of its potential metabolites in the seeds during 1 year following the conditioning. The control seeds and those conditioned with water contained small amount of endogenous melatonin in both species. However, the level of this indoleamine increased markedly in cucumber and corn seeds primed with exogenous melatonin and it was always correlated with the concentration of melatonin applied. It was noted that melatonin was metabolized during seed storage by its gradual oxidation, thus it protects dry seeds against oxidative stress, prevents potential injuries and significantly increases seeds quality. Interestingly, in the control and water-primed seeds, seasonal fluctuations of endogenous melatonin concentration were noted and significant increase in this indoleamine in the winter month was observed. This suggests that in seeds endogenous melatonin could play a crucial role in seasonal rhythms independently of environmental conditions.

Melatonin restricts Pb-induced PCD by enhancing BI-1 expression in tobacco suspension cells

“…2). The same phenomenon was observed in a case of cucumber and corn seeds that were osmo- or hydroprimed with exogenous melatonin (Kołodziejczyk et al 2015)—they absorbed great quantities of indoleamine proportionally to its concentration applied during priming. Interestingly in presented results, Pb-stressed cells (MEL + Pb) absorbed melatonin under harmful conditions more intensively in comparison to unstressed (MEL) ones.…”

“…This fact together with melatonin small size makes it particularly able to migrate easily between cell compartments in order to protect them against excessive ROS. Moreover, recent evidence indicates that the melatonin metabolites (Kolodziejczyk et al 2015), e.g. cyclic-3-hydroxymelatonin, 2-hydroxylmelatonin and especially N1-acetyl-N2-formyl-5-methoxykynuramine (AFMK) also posses antioxidant abilities.…”

Melatonin redirects carbohydrates metabolism during sugar starvation in plant cells

“…Melatonin acts as a direct antioxidant; moreover, it may also regulate activities of several antioxidant enzymes including superoxide dismutase, catalase, ascorbate peroxidase, glutathione peroxidase and glutathione reductase . Additionally, recent evidence indicates that the melatonin metabolites, for example cyclic‐3‐hydroxymelatonin, 2‐hydroxylmelatonin and especially N1‐acetyl‐N2‐formyl‐5‐methoxykynuramine (AFMK) also possess antioxidant abilities . Among many functions which melatonin plays in plants, its role as an antioxidant and growth promoter is mostly supported by experimental evidence .…”

Melatonin Application to Pisum sativum L. Seeds Positively Influences the Function of the Photosynthetic Apparatus in Growing Seedlings during Paraquat-Induced Oxidative Stress

“…In relation to this, exogenous melatonin application into the seeds using different priming methods has proven highly effective (Posmyk et al, 2008, 2009a,b; Janas et al, 2009; Szafrańska et al, 2012, 2013, 2014; Kołodziejczyk et al, 2015). …”