Effects Heavy metals and NaCl on Growth and Aldh Experession in Lycopersicum Esculentum Var Srijasna

Abstract

A greenhouse pot experiment was conducted to determine the effects of heavy metals (Cd, Pb) and NaCl on growth morphology, accumulation, and ALDH expression in Lycopersicumesculentum Var Srijana. The experiments were performed to examine the effects on the seed germination, root elongation, shoot elongation, Al dehyde dehydrogenase (ALDH) expression and accumulation of Pb, Cd and Na in the selected tomato variety grown on soil-verm icompost substrate supplemented with different concentration of Pb(NO3)2, CdCl2and NaCl. The selected heavy metals were treated in different concentrations ranging from 0.1, 0.3, 0.5, 1 mM and salt (NaCl) in 25, 50, 75, 100 mM separately in soil – vermicom post media (2:1) in plastic pots. The seed germination, root and shoot growth were affected by these treatments at higher concentrations. The increasing concentrations of heavy metals and salt treatments have in hibitory effects on germination, root length (RL), shoot length (SL)thoughthe plants seemto germinate and grow efficiently at all treatments.Treatments at lower concentration of Pb(NO3)2(at 0.3, 0.5mM) and of salt (at 50 mM) doses, were found to be stimulating the root and shoot elongation whereasat higher concentration of heavy metals(at 1 mM of Pb(NO3)2, CdCl2) andNaCl (at 75mM, 100mM) causes the delayed germination and retardationin root and shoot length.Aldehyde dehydro genases (ALDHs) play a major role inthe detoxification processes of aldehydes generated inplants in various metabolism and when exposed to abiotic stress. ALDH catalyzes the oxidation of the chemically toxic aldehydes intermediates into corresponding carboxylic acids, reducing pyridine nucleotide. The simplest method of ALDH assay is spectrophotometric method and is used in this study. The spectrophotometric reading showed to have highest activity (693.39 mIU/mg proteins) at 0.3 mM CdCl2 treatment after2ndweek of stress exposure. It was also found that the lower doses of stresses are more efficient at inducing greater ALDH responses than higher doses which shows lower ALDH activity. NATIVE-PAGE of the same prepared samples showed some bandswhich confirmed that the spectrophotometric measurements was of ALDH. The number, type and character of the isotypes of ALDH produced but couldn’t be characterized.Some additional bandsin treatment plant tissue homogenate samplescan be regarded as produced due to stress exposure. The metal accumulation experiments performedunder stress ofPb(NO3)2, CdCl2and NaCl suggests that their uptake takes place at all treatments. The metals were determined by using atomic absorption spectrophometry (AAS). Highest uptake of heavy metal occurs at 1mMPb(NO3)2 and Na at 100mMNaCltreatments and least accumulation occurs at 0.1 mMPb(NO3)2 and 25 mMNaCl.From this study, it can also be concluded that the amount of accumulation increases as the concentration of heavy metals and Na increases in the substrate. Aldehyde dehydrogenase, Lycopersicumesculentum var Srijana, Abiotic stress, Heavy metals, Uptake