Terminalia arjuna bark extract alleviates nickel toxicity by suppressing its uptake and modulating antioxidative defence in rice seedlings.
Terminalia arjuna (Ta) bark contains various natural antioxidants and has been used to protect animal cells against oxidative stress. In the present study, we have examined alleviating effects of Ta bark aqueous extract against Ni toxicity in rice (Oryza sativa L.). When rice seedlings were raised for 8 days in hydroponics in Yoshida nutrient medium containing 200 μM NiSO4, a decline in height, reduced biomass, increased Ni uptake, loss of root plasma membrane integrity, increase in the level of O2˙-, H2O2and ˙OH, increased lipid peroxidation, decline in photosynthetic pigments, increase in the level of antioxidative enzymes superoxide dismutase, catalase and glutathione peroxidase and alterations in their isoenzyme profile patterns were observed. Transmission electron microscopy (TEM) showed damage to chloroplasts marked by disorganised enlarged starch granules and disrupted thylakoids under Ni toxicity. Exogenously adding Ta bark extract (3.2 mg ml-1) to the growth medium considerably alleviated Ni toxicity in the seedlings by reducing Ni uptake, suppressing generation of reactive oxygen species, reducing lipid peroxidation, restoring level of photosynthesis pigments and ultrastructure of chloroplasts, and restoring levels of antioxidative enzymes. Results suggest that Ta bark extract considerably alleviates Ni toxicity in rice seedlings by preventing Ni uptake and reducing oxidative stress in the seedlings.
Department of Biochemistry, Faculty of Science, Banaras Hindu University, Varanasi, 221005, Uttar Pradesh, India.
Ritika
R
Rajpoot
Department of Biochemistry, Faculty of Science, Banaras Hindu University, Varanasi, 221005, Uttar Pradesh, India.
Anjana
A
Rani
Department of Biochemistry, Faculty of Science, Banaras Hindu University, Varanasi, 221005, Uttar Pradesh, India.
Rajneesh Kumar
RK
Srivastava
Department of Biochemistry, Faculty of Science, Banaras Hindu University, Varanasi, 221005, Uttar Pradesh, India.
Poonam
P
Pandey
Department of Biochemistry, Faculty of Science, Banaras Hindu University, Varanasi, 221005, Uttar Pradesh, India. rsdbhu@rediffmail.com.
R S
RS
Dubey
D000975:Antioxidants / Q000378:metabolism*; D002338:Carotenoids / Q000378:metabolism; D002374:Catalase / Q000378:metabolism; D002462:Cell Membrane / Q000378:metabolism; D002734:Chlorophyll / Q000378:metabolism; D002736:Chloroplasts / Q000187:drug effects / Q000378:metabolism / Q000648:ultrastructure; D006861:Hydrogen Peroxide / Q000378:metabolism; D015227:Lipid Peroxidation / Q000187:drug effects; D009532:Nickel / Q000633:toxicity*; D012275:Oryza / Q000187:drug effects / Q000378:metabolism*; D009195:Peroxidase / Q000378:metabolism; D024301:Plant Bark / Q000737:chemistry*; D010936:Plant Extracts / Q000494:pharmacology*; D018515:Plant Leaves / Q000378:metabolism; D018517:Plant Roots / Q000187:drug effects / Q000378:metabolism; D018520:Plant Shoots / Q000187:drug effects / Q000378:metabolism; D036226:Seedlings / Q000187:drug effects / Q000378:metabolism*; D013482:Superoxide Dismutase / Q000378:metabolism; D013481:Superoxides / Q000378:metabolism; D029766:Terminalia / Q000737:chemistry*; D014867:Water / Q000378:metabolism
D000975:Antioxidants; D010936:Plant Extracts; D014867:Water; D013481:Superoxides; D002734:Chlorophyll; D002338:Carotenoids; D009532:Nickel; D006861:Hydrogen Peroxide; C121048:guaiacol peroxidase; D002374:Catalase; D009195:Peroxidase; D013482:Superoxide Dismutase
Antioxidant activity; Chloroplast ultrastructure; Nickel toxicity; Rice seedlings; Terminalia arjuna