Changes in the nature of phenolic deposits after re-warming as a result of melatonin pre-sowing treatment of Vigna radiata seeds

Involvement of melatonin applied to Vigna radiata L. seeds in plant response to chilling stress

“…Our results provide indirect evidence that rapid seed water uptake during hydro-priming induced oxidative stress, which has been previously demonstrated by increasing TBARS content [22]. These observations are consistent with those of Bailly et al [40] and may suggest that seed water uptake during hydro-priming triggers large H 2 O 2 production, causing disorders in the functioning of the membrane.…”

“…This effect was maintained in both chilled and re-warmed H-roots, suggesting the occurrence of irreversible changes in membrane integrity, a phenomenon frequently observed in chilling-sensitive tissues [41]. In H-MEL roots, % of electrolyte leakage decreased after re-warming (Table 1), which seems to confirm our previous suggestion about a protective role of MEL when the stress factor is removed [22]. In another study, shrinkage and disruption of plasma membrane caused by chilling were almost completely inhibited by MEL treatment in the suspension of carrot cells, suggesting that MEL is also involved in the integrity of membranes [9].…”

“…Then the seedlings were divided into 2 groups: one of them was exposed to 5°C for 2 days (5 C), the other was kept under optimal conditions (25°C) (25 C). Chilled seedlings were placed back to 25°C for 2 days (5C+Reg) for evaluation of biochemical changes in roots caused by chilling [22].…”

“…Fresh roots (0.5 g) were extracted by 5 mL of 96% Et-OH and the total phenolic contents were determined using a modified Folin-Ciocalteu colorimetric method [22]. Total phenolics were calculated from the gallic acid standard curve and expressed as milligram gallic acid equivalents per gram of fresh weight (mg GAE g −1 FW).…”

Yellow deposits formation in roots is a part of tobacco plant phenotype under sulfur deficiency

“…Such alteration, taken together with the eye-visible color difference, between the ethanol extracts analyzed in the experiments, point to the UV absorbing compounds (UVAC) as a reason of yellow color. The most abundant group of such molecules, reported as responsible for most of the changes of extract spectra in UV range are phenolic compounds (25,26). Noteworthy, phenolics (mostly the subgroup called flavonoids) are, besides chlorophylls, the main group of compounds that affect color of plant organs.…”