Journal of Environmental Biology

Effect of nickel-stresses on uptake, pigments and antioxidative

responses of water lettuce, Pistia stratiotes L.

Author Details

Kavita Singh

Botany Department, Lucknow University, Lucknow - 226 007, India

S.N. Pandey

(Corresponding author)

Botany Department, Lucknow University, Lucknow - 226 007, India

e-mail: snpandey511@gmail.com

Publication Data

Paper received:

07 October 2009

Revised received:

05 May 2010

Re-revised received:

25 August 2010

Accepted:

24 September 2010

Abstract

Water lettuce plants were exposed to various concentrations (0, 0.01, 0.1, 1.0 and 10.0 ppm) of nickel as nickel sulphate in nutrient medium. The effect of graded nickel (Ni⁺²) concentrations on visible symptoms of toxicity, pigments (chlorophyll a, b and total) and antioxidative attributes were evaluated. Plants exposed to high nickel (1.0 and 10.0 ppm) showed visible toxicity symptoms, such as wilting, chlorosis in young leaves, browning of root tips and broken off roots, observed at 6 days after treatment. Nickel was accumulated more in root (863.3 ?g g^-1 dry weight) than leaves (116.2 ?g g^-1 dry weight) at 6 days of treatment. Nickel exposure decreased chlorophyll a, b and total chlorophyll contents. Relative water content decreased at high nickel (1.0 and 10.0 ppm). Antioxidants, such as proline content and peroxidase activity increased with increase in nickel concentrations, whereas, other carotenoids and protein contents at 1.0 ppm and activity of catalase at 10 ppm of nickel were decreased. The low level of nickel stimulates photosynthetic pigments and antioxidative attributes. The study may be helpful in phytoremedial strategies and biological indication of nickel toxicity in aquatic plants.

Key words

Nickel-stresses, Antioxidative responses, Pistia stratiotes L., Phytoremediation

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