Journal of Environmental Biology

Physiological changes in certain test plants under automobile exhaust pollution

 

Madhumanjari Mandal

Department of Botany, Scottish Church College, 1& 3 Urquhart Square, Kolkata- 700 006, India

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(Received: 22 April, 2004 ; Accepted: 25 October, 2004)

 

Abstract: Plants are the only living organisms which have to suffer a lot from automobile exhaust pollution because they remain static at their habitat. But such roadside plants like Nerium indicum Mill., Boerhaavia diffusa L., Amaranthus spinosus L., Cephalandra indica Naud., and Tabernaemontana divaricata L. can easily avoid the effects of air pollution by altering their physiological pathways pertaining to photosynthesis and respiration. Stomatal closure in Boerhaavia, Amaranthus, Cephlandra and stomatal clogging in Nerium and Tabernaemontana help these plants in preventing the entry of poisonous gases. The increased activity of the enzyme Phosphoenol Pyruvate Carboxylase (PEPCase) belonging to C₄ pathway helps Nerium and Boerhaavia (both C₃ plants) in carbon fixation under stress condition. Photorespiration is favoured in Amaranthus, Cephalandra and Tabernaemontana to compensate for the over production of ATP in them. Owing an inefficient gaseous exchange in Boerhaavia and Tabernaemontana, the activity of Glucose 6 - Phosphate Dehydrogenase (G6-PD) also increases for the preferential shift to Pentose Phosphate Pathway to produce excess NADPH+H⁺ which are likely to re-oxidize by metabolic reactions not linked to electron transport chain.

 

Key words: Automobile exhaust, Plants, Anaerobic respiration, Fructose 1,6-bis phosphate aldolase, Posphoenol pyruvate carboxylase, Glucose 6 phosphate dehydrogenase.

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