Physiological changes in certain test plants under automobile exhaust pollution.

Area of Science:

• Environmental Science
• Plant Physiology
• Biochemistry

Background:

• Plants are sessile organisms vulnerable to environmental stressors like automobile exhaust pollution.
• Roadside vegetation faces significant exposure to pollutants, necessitating adaptive strategies.

Purpose of the Study:

• To investigate the physiological and biochemical adaptations of specific roadside plants to automobile exhaust pollution.
• To understand how plants modify photosynthesis and respiration to mitigate pollutant effects.

Main Methods:

• Comparative analysis of physiological responses in selected plant species (Nerium indicum, Boerhaavia diffusa, Amaranthus spinosus, Cephalandra indica, Tabernaemontana divaricata).
• Enzyme activity assays for Phosphoenol Pyruvate Carboxylase (PEPCase) and Glucose 6--Phosphate Dehydrogenase (G6-PD).
• Assessment of stomatal responses (closure and clogging) and photorespiration rates.

Main Results:

• Stomatal closure observed in Boerhaavia, Amaranthus, and Cephalandra; stomatal clogging in Nerium and Tabemaemontana.
• Increased PEPCase activity in Nerium and Boerhaavia facilitated carbon fixation under stress.
• Enhanced photorespiration in Amaranthus, Cephalandra, and Tabernaemontana compensated for ATP overproduction.
• Elevated G6-PD activity in Boerhaavia and Tabemaemontana indicated a shift to the Pentose Phosphate Pathway for NADPH+H+ production.

Conclusions:

• Roadside plants exhibit diverse physiological and biochemical adaptations to cope with automobile exhaust pollution.
• Altered stomatal function, modified carbon fixation pathways (C4 enzyme activity in C3 plants), and regulated photorespiration are key survival strategies.
• The Pentose Phosphate Pathway plays a role in managing metabolic stress in certain plant species exposed to pollution.