Chromium (VI) accumulation reduces chlorophyll biosynthesis, nitrate reductase activity and protein content in Nymphaea alba L

• Published in: Chemosphere (Oxford) Vol. 41; no. 7; pp. 1075 - 1082
• Main Authors: Vajpayee, P, Tripathi, R.D, Rai, U.N, Ali, M.B, Singh, S.N
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01-10-2000; Elsevier
• Subjects: aminolevulinic acid; Animal, plant and microbial ecology; Applied ecology; Biological and medical sciences; biosynthesis; chemical constituents of plants; chlorophyll; Chlorophyll - biosynthesis; chromium; Chromium - toxicity; Dose-Response Relationship, Drug; Ecotoxicology, biological effects of pollution; Effects of pollution and side effects of pesticides on plants and fungi; enzyme activity; Fundamental and applied biological sciences. Psychology; ion transport; leaves; Nitrate Reductase; Nitrate Reductases - metabolism; Nymphaea alba; phytotoxicity; Plant Development; Plants - drug effects; Plants - enzymology; porphobilinogen synthase; protein content; Proteins - analysis; rhizomes; roots; Water Pollutants - toxicity; Toxicity; Lyases; Biosynthesis; Enzymatic activity; Dicotyledones; Angiospermae; Rhizome; Aquatic plant; Chlorophyll; Porphobilinogen synthase; Root; Enzyme; Plant leaf; Nymphaeaceae; Heavy metal; Pollutant; Phytotoxicity; Nitrate reductase; Spermatophyta; Water pollution; Oxidoreductases; Biological accumulation; Carbon-oxygen lyases; Chromium VI; Hydro-lyases
• ISSN: 0045-6535; 1879-1298
• DOI: 10.1016/S0045-6535(99)00426-9

Plants of
Nymphaea alba L. grown at various levels of chromium (VI) ranging from 1 to 200 μM accumulated chromium in concentration and duration-dependent manner. At all Cr levels, chromium accumulation by various plant tissues followed the order roots
>
leaves
>
rhizomes. Approximately 93% of total chromium present in the medium was accumulated by plants at lowest conentration (1 μM) used in the experiment. Chromium-induced toxicity appears at 1 μM chromium resulting in the build-up of δ-aminolevulinic acid (ALA) and reduced activities of δ-aminolevulinic acid dehydratase (ALAD) and nitrate reductase (NR), total chlorophyll (Chl) and protein contents. Chl
a was more sensitive than Chl
b to chromium toxicity. It could be inferred that chromium toxicity is not located at the level of ALA synthesis, but, probably at the ALAD activity which was more severely affected during chlorophyll biosynthesis. Finally, impaired chlorophyll biosynthesis resulted in reduced total chlorophyll content.