Toxicity of Agricultural Herbicide  2, 4–Dichlorophenoxyacetic  acid on growth, Photosynthesis and  Respiration of Rice Field Cyanobacterium

Bhagya Lakshmi Jyothi. K.

Volume : II, Issue : VIII, August - 2013

Toxicity of Agricultural Herbicide 2, 4–Dichlorophenoxyacetic acid on growth, Photosynthesis and Respiration of Rice Field Cyanobacterium

Bhagya Lakshmi Jyothi. K.

Abstract :

One of the most commonly used paddy field herbicide in India is 2, 4-Dichlorophenoxy acetic acid. A study was conducted to investigate the toxic effect of 2, 4-D on the growth, cellular metabolites, rate of photosynthesis, (O2 evolution) and rate of respiration (O2 consumption) in a Synechococcus aeruginosus collected from rice field soils of Krishna district, Andhra Pradesh, India and grown in Hughe�s medium (1958) as modified by Allen (1968). An experiment was designed to find out the toxic effect of 2, 4-D on the growth of Cyanobacterium when exposed to different concentrations and time intervals incubated at 500, 800 and 1000 mg per ml concentration of herbicide for 0, 24 and 48 hrs time intervals. The increasing dose of 2,4-D and treated / incubation time (immediately on the addition of chemical 0,24and48 hours)gradually declined the rate of photosynthesis and respiration. The herbicide reduced the cellular metabolites gradually with the increase of 2,4-D concentration and exposure time.