Reversal of the inhibitory effect of light and high temperature on germination of Phacelia tanacetifolia seeds by melatonin

Abstract

Possible role of melatonin in the germination of negatively photoblastic and thermosensitive seeds of Phacelia tanacetifolia Benth was studied. Final germination percentage (FGP) was determined in the presence or absence of light at various temperatures, ranging from 0 to 40°C. The highest FGP was determined as 48.7% and 92% at temperature of 15°C in the presence and absence of light, respectively. Seeds were primed with 1% KNO(3) containing various concentrations (0.3, 1, 6, 12, 30, 60, or 90 μM) of melatonin for 2 days at 15°C in darkness. Primed seeds were germinated at an inhibitory temperature of 30°C, and results were compared to those occurring at the optimum temperature of 15°C under both light and no light conditions. Melatonin incorporated into priming medium significantly reversed the inhibitory effects of light and high temperature. Germination was elevated from 2.5% to 52% of FGP for seeds primed in the presence of 6 μM melatonin in darkness at 30°C, while 1 μM melatonin had the highest FGP (21.0%) in the presence of light at 30°C. The highest FGP (47.5%) was obtained from seeds primed in the presence of 0.3 μM melatonin under the light condition at 15°C, while untreated seeds had 1.5% of FGP. The fastest seed germination was determined from seeds primed in the presence of 0.3 μM melatonin (G(50) = 0.56 days) at 15°C in darkness. The possible roles of melatonin in promoting germination parameters of photo- and thermosensitive seed germination are discussed.

A new balancing act: The many roles of melatonin and serotonin in plant growth and development

“…Additionally, though much research has been done to investigate the presence and activity of MEL in plants, new analytical technologies have led to the identification of many possible isomers of MEL, which have not been studied in depth 45 compound in the protection of plants against stresses which were recently reviewed by several authors including refs 42,46,47 and include biotic stresses such as pathogen attack and diverse abiotic stresses including drought, freezing, osmotic, heat, heavy metal, UV and oxidative stresses; 5HT has some similar actions in some plant species 42,[47][48][49][50][51][52][53][54][55][56][57][58][59][60][61][62][63][64] .…”

Cloning of Arabidopsis serotonin N‐acetyltransferase and its role with caffeic acid O‐methyltransferase in the biosynthesis of melatonin in vitro despite their different subcellular localizations

“…Its levels vary between species, ranging from a few picograms to micrograms per gram of tissue [11]. Melatonin is implicated in pleotropic functions in plants as a potent antioxidant [12], growth promoter [13,14], flowering and senescence inhibitor [15,16], and protector against various abiotic and biotic stresses such as salt, heavy metals, temperatures, drought, and pathogens [17][18][19][20][21][22]. These physiological functions of melatonin are closely associated with a diverse array of gene regulation in response to melatonin [23][24][25][26].…”

Cloning and Phylogenetic Analysis of Brassica napus L. Caffeic Acid O-Methyltransferase 1 Gene Family and Its Expression Pattern under Drought Stress

“…Melatonin is implicated in pleiotropic functions during plants growth and development [17]. In addition, the importance of melatonin in plant protection against stresses including water [18], cold [19], high temperature [20], salt [21], oxidative stress [22], senescence [23], herbicides [22], and pathogens [24] has been reported. COMT is also thought to be responsible for the last step of melatonin biosynthesis by catalysing serotonin into melatonin with an intermediate 5-methoxytryptamine (5-MT) in plants [15].…”