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International Conference on

Recent Trends in Environmental Sustainability

ESCON22/ETERM/34
Physiological responses of Pistia stratiotes and Alternanthera philoxeroides against
arsenic stress in growth medium

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Muatter Zafar , Hafiz Faiq Siddique
1 Department of Environmental Sciences, COMSATS University Islamabad, Vehari-campus,
Pakistan
Correspondence: Faiqsiddique@cuivehari.edu.pk

Abstract
Arsenic (As) contamination is now a serious issue of global concern and have severe negative
impacts on biosphere. The metalloid is not an essential to the biosphere and its contamination
via water, soil and food can trigger several disturbances in metabolic processes in the bio-
systems. In Pakistan recently research has been done on As contamination specifically in
groundwater which highlighted the seriousness and amount of As present in adjoining areas of
the Indus river and its surroundings. The current study was carried out to determine the
physiological responses of two different aquatic plant species namely water cabbage (Pistia
stratiotes) and alligator weed (Alternanthera philoxeroides) were exposed to various levels of
As. Arsenic concentrations maintained in the growth medium were; 0, 50, 100, 200, and 400
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µg L for 28 days and plants were monitored for the growth, physiological changes and As
accumulation. Plants were harvested after 28 days to examine the changes in growth,
physiology (antioxidative enzymes, chlorophyll contents, and lipid-peroxidation) and ions
(phosphorus, As, potassium and calcium) concentrations in plants grown under As stress.
Results indicate that water cabbage growth remained un-affected while growth of the alligator
weed was significantly reduced. In addition, both plants species did not show any toxicity
symptoms in terms of H2O2 production as well as lipid peroxidation. Similarly, the plants did
not show any change in antioxidative response and enzymatic activities in treated and non-
treated plants were alike. Both plant species maintained ionic homeostasis and cation uptake
i.e Na, K, Ca and Li were un-affected in the presence of As in the growth medium. The results
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of As in plant shows that changing concentration from 0 to 50 µg L had resulted in a
significant increase in As accumulation by both plant species. Plant exposure beyond 50 µg L -
1 did not changed the As accumulation in both plant species. From these results we can
conclude that both plant species have the ability to maintain low As in shoot tissue with
minimal bio-chemical changes. Form the results we can speculate that the tested plant species
have the ability to change the growing conditions through ex-planta mechanisms and sustain
their growth.

Keywords: Antioxidant; Arsenic; Cabbage; Stress

Department of Environmental Sciences, COMSATS University Islamabad, Vehari Campus

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