Int. J. Bioinformatics and Biological Sci.: v.2 n.1&2, p. 13-22. March and June 2014

Lead Stress-induced changes of antioxidant Enzymes

and Biochemical compounds in Selected Weeds and

their contribution for Phytoremediation

g. Hanumanth Kumar and K.v. Saritha*

Department of Biotechnology, Sri Venkateswara University, Tirupati, A.P -517502, INDIA

*Corresponding author: K.V. Saritha, kvsarithasvu@gmail.com

abstract

Investigation was carried out to identify tolerant plant species growing

in lead contaminated soil. Lead effected Chlorophyll a, chlorophyll b

and ascorbicacidoxidase. Induced malondialdehyde and starch contents

with up-regulated activities of antioxidative enzymes like catalase and

phenylalanineammonialyase were observed. Enzymatic activities have been

enhanced in all plants taken indicating that free radical generation was accelerated

due to Pb exposure . Concentrations of lead accumulated were Calotropis procera

(90 mg/kg) and Bromus tectorum (77 mg/kg) are higher followed by Ipomea

purpurea (72 mg/kg), Parthenium histocarpus (33 mg/kg), Anisomilius molabarica

(29 mg/kg) and Eichornia fasculata (10 mg/kg). Inspite of accumulation all plants

survived successfully. With our findings we can suggest these plants can be used

for effective phytoremediation of lead.

Keywords :

Free

radicals,

Lead,

Up-regulated,

Malondialdehyde,

Phytoremediation.

Heavy metal pollution of soils has been increasingly becoming a global problem

which poses several risks to human health, decreased soil microbial activity,

fertility and yield losses (McGrath, 1995). Inspite of all expensive extraction

technologies like chelating and land filling, Phytoremediation is an emerging

cheap cleanup technology, which uses green plants to remove, contain or render

harmless environmental contaminants.

In heavymetals Lead (Pb) is one of the most abundant heavy metal pollutants in

terrestrial and aquatic environments. Lead induces free radicals in various plant

speciesbyinductionoflipidperoxidationandgenerationofreactiveoxygenspecies

which inhibits metabolic processes such as nitrogen assimilation, photosynthesis,

respiration, water uptake and transcription (Boussama et al. , 1999). Lead causes

two types of unfavorable processes in biological systems: (I) it inactivates several