Increasing sulfur supply enhances tolerance to arsenic and its accumulation in Hydrilla verticillata (Lf.) Royle.
The present study was aimed to analyze the effects of variable S supply on arsenic (As) accumulation potential of Hydrilla verticillata (Lf.) Royle. Plants were exposed to either arsenate (AsV; 50 microM) or arsenite (AsIII; 5 microM) for 4 h and 1 day while S supply was varied as deficient (2 microM, -S), normal (1 mM, +S) and excess (2 mM, +HS). The level of As accumulation (microg g(-1) dw) after 1 day was about 2-fold higher upon exposure to either AsV (30) or AsIII (50) in +HS plants than that being in +S (12 and 24) and -S (14 and 26) plants. The +HS plants showed a significant stimulation of the thiol metabolism upon As exposure. Besides, they did not experience significant toxicity, measured in terms of malondialdehyde accumulation; an indicator of oxidative stress. By contrast, -S plants suffered from oxidative stress probably due to negative impact to thiol metabolism. Variable S supply also modulated the activity of enzymes of glycine and serine biosynthesis indicating an interconnection between S and N metabolism. In conclusion, an improved supply of S to plants was found to augment their ability for As accumulation through stimulated thiol metabolism.
Srivastava
Sudhakar
S
Nuclear Agriculture and Biotechnology Division, Bhabha Atomic Research Centre, Trombay, Mumbai-400085, India.
D'Souza
S F
SF
D000222:Adaptation, Physiological / Q000187:drug effects*; D001149:Arsenates / Q000633:toxicity; D001151:Arsenic / Q000378:metabolism* / Q000633:toxicity*; D018053:Arsenites / Q000633:toxicity; D003547:Cysteine Synthase / Q000378:metabolism; D005721:Glutamate-Cysteine Ligase / Q000378:metabolism; D031321:Hydrocharitaceae / Q000187:drug effects* / Q000201:enzymology / Q000378:metabolism*; D008315:Malondialdehyde / Q000378:metabolism; D050862:Oxidoreductases Acting on Sulfur Group Donors / Q000378:metabolism; D051050:Serine O-Acetyltransferase / Q000378:metabolism; D013431:Sulfates / Q000378:metabolism; D013438:Sulfhydryl Compounds / Q000378:metabolism; D013455:Sulfur / Q000494:pharmacology*
D001149:Arsenates; D018053:Arsenites; D013431:Sulfates; D013438:Sulfhydryl Compounds; D008315:Malondialdehyde; D013455:Sulfur; D050862:Oxidoreductases Acting on Sulfur Group Donors; C019618:adenylylsulfate reductase; D051050:Serine O-Acetyltransferase; D003547:Cysteine Synthase; D005721:Glutamate-Cysteine Ligase; C015001:arsenite; D001151:Arsenic; C025657:arsenic acid