Assessment of impact of nickel stress on the accumulation, pigments and protein content of water hyacinth (Pontederia crassipes L.)

Abstract

Pontederia crassipes L. plants were collected and exposed to different concentrations (Control, 0.01, 0.1, 1.0 and 10.0 ppm) of Ni by using NiSO4 in medium in the laboratory. The effect of Ni2+ concentrations on visible symptoms such as toxicity, pigments (Chlorophyll- a, b and total) contents were estimated. Plants exposed to high nickel (1.0 and 10.0 ppm) showed visible toxicity symptoms such as wilting, chlorosis in young leaves, browning of roots noticed after 6 days of treatment. Nickel was accumulated more in stem (651.1µg/g dry weight) than leaves (115.23 µg/g dry weight) at 6 days of treatment. Nickel exposure decreased Chlorophyll-a, b and total chlorophyll contents. Body water content decreased at high nickel (1.0 and 10.0 ppm). Increased nickel concentrations increases antioxidants such as proline content. On the other hand carotenoids and protein contents at 1.0 ppm of nickel were decreased. The low level of nickel stimulates photosynthetic pigments and antioxidative parameters.