title: Lead (Pb)-inhibited radicle emergence in Brassica campestris involves alterations in starch-metabolizing enzymes.
abstract: Lead (Pb) is a toxic heavy metal released into the natural environment and known to cause oxidative damage and alter antioxidant mechanism in plants. However, not much is known about the interference of Pb with the biochemical processes and carbohydrate metabolism during seed germination. We, therefore, investigated the effect of Pb (50-500 μM) upon biochemical alterations in germinating seeds (at 24-h stage) of Brassica campestris L. Pb treatment significantly enhanced protein and carbohydrate contents that increased by ~43% and 200%, respectively, at 500-μM Pb over control. In contrast, the activities of starch/carbohydrate-metabolizing enzymes--α-amylases, β-amylases, acid invertases, and acid phosphatases--decreased by ~54%, 60%, 74%, and 52%, respectively, over control. Activities of peroxidases and polyphenol oxidases, involved in stress acclimation, however, increased by ~1.2- to 3.9-folds and 0.4- to 1.4-folds upon 50-500-μM Pb treatment. Pb enhanced oxidizing ability by 10 to 16.7 times over control suggesting interference with emerging root's oxidizing capacity. The study concludes that Pb exposure inhibits radicle emergence from B. campestris by interfering with the biochemical processes linked to protein and starch metabolism.
authors: Department of Environment Studies, Panjab University, Chandigarh, 160014, India. hpsingh_01@yahoo.com
authors: Harminder Pal
authors: HP
authors: Singh
authors: Gurpreet
authors: G
authors: Kaur
authors: Daizy R
authors: DR
authors: Batish
authors: Ravinder K
authors: RK
authors: Kohli
mesh_terms: D000135:Acid Phosphatase / Q000378:metabolism; D000681:Amylases / Q000378:metabolism; D001937:Brassica / Q000187:drug effects / Q000201:enzymology* / Q000378:metabolism*; D050260:Carbohydrate Metabolism / Q000187:drug effects; D004156:Catechol Oxidase / Q000378:metabolism; D018525:Germination / Q000187:drug effects; D007854:Lead / Q000494:pharmacology*; D010084:Oxidation-Reduction; D010447:Peptide Hydrolases / Q000378:metabolism; D010544:Peroxidases / Q000378:metabolism; D010940:Plant Proteins / Q000096:biosynthesis; D018517:Plant Roots / Q000737:chemistry / Q000378:metabolism; D012639:Seeds / Q000187:drug effects; D013213:Starch / Q000378:metabolism*; D043324:beta-Fructofuranosidase / Q000378:metabolism
chemical_list: D010940:Plant Proteins; D007854:Lead; D013213:Starch; D004156:Catechol Oxidase; D010544:Peroxidases; D000135:Acid Phosphatase; D000681:Amylases; D043324:beta-Fructofuranosidase; D010447:Peptide Hydrolases