Regulation of growth and biomolecule of Aphanothece sp. by phenoxy herbicide 2, 4-d

A. K. Pandey¹, P. N. Dongre¹, Y. K. Singh¹ and S. N. Tiwari²

¹Biological Research Lab. Department of Botany and Biotechnology Kutir P.G. College Chakkey, Jaunpur - 222 146 (India) ²P.G. Department of Botany, K.N.P.G. College Gyanpur, S.R.N.(Bhodohi) (India)

ABSTRACT: Toxicity of the herbicide 2, 4-Dichlorophenoxy acetic acid to unicellular cyanobacterium Aphanothece Sp. has been studied. Stimulation in cyanobacterial growth was observed at 100 ug ml-1 while higher concentrations had inhibitory effect with 1600 μg ml-1 being completely lethal. The sublethal concentration (1200 μg ml-1) allowed few cell (frequency approx 10-7) of cyanobacterium population into filamentous aseptate structure and regained the normal course of the unicellular pattern of differentiation in absence of the herbicide. 2, 4-D resulted in decline of chlorophyll a and no effect on DNA content even at the growth stimulatory concentration (100 μg ml-1). However, cell protein, RNA and phycobillin contents were increased up to 400 μg ml-1 , while higher concentrations have inhibitory effects. Cellular abnormalities by higher concentration and possible mode of action of 2, 4-D at the level of cell division are discussed.

KEYWORDS: Growth Biomolecules; Aphanothece sp. Phenoxy herbicide, 2, 4-D

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