Combined Action of Melatonin and Water Deficiency on Growth and MDA Content of Hypocotyls and Roots of Lupine and Respiration of Mitochondria Isolated from These Organs

Abstract Melatonin is known to improve the tolerance of plants adverse abiotic factors (AAF), including dehydration. Nevertheless, details action this phytohormone are not sufficiently comprehended. In current study, effects melatonin on growth, water status, and content malonic dialdehyde were evaluated in etiolated seedlings narrow-leaved lupine ( Lupinus angustifolius L.) subjected The respiration mitochondria isolated from different organs these was also analyzed. Here, 4-day-old have been deprived for 1 day. This entailed increased deficit up 22% roots 6% hypocotyls. Such desiccation retarded growth their hypocotyls but that by 13% comparison with undesiccated control. Both root hypocotyl tissues accumulated MDA under conditions. dehydration negatively affected organs. rate oxidation substrates, especially malate, diminished at metabolic State 3 mainly due an inhibition cytochrome pathway (CP). For example, upon activity CP decreased 1.8 times four five those roots. Pretreatment 0.1 µM prevented dehydration-induced rise level but, contrast, stimulated parameter 27% Under drought conditions combined exogenous melatonin, close control, while lower than normally supplied water, treatment did significantly influence prepared or However, shortage, completely blocked a substrate mitochondria, chiefly because sustaining activity. As result, malate 87% succinate 26% state Application hormone only partially reversed oxidative phosphorilation mitochondria. case, respiratory succinate, still inhibited. Possible causes differences between cells seedling responses deficit, namely, extent stress functions discussed.