Growth and metabolic activities of cowpea seedlings exposed to artificial pond wastewater‑treated soil

Abstract

Purpose The increase in demand for fish has necessitated the establishment of fish pond. The discharge of spent pond water pollutes the adjoining surroundings. The aim of this investigation was to determine the suitability of artificial pond wastewater (APWW) as source of manure for crop cultivation. Method Cowpea seeds were planted in polybags containing soil treated with varied amount of artificial pond wastewater. Thereafter, growth and various metabolic properties of cowpea seedlings were determined using standard procedures. Results Artificial pond wastewater treatment of soil increased significantly (P<0.05) the growth parameters, content of biomolecules and activities of alpha amylase, starch phosphorylase and peroxidase when compared to the control. Exposure of the seedlings to APWW did not alter most oxidative stress markers compared to the control. In addition, APWW in soil significantly (P<0.05) increases the levels of vitamin C but had no alterations in the activities of succinate dehydrogenase (SDH), lactate dehydrogenase (LDH) and sulphite oxidase (SO) of the cowpea seedlings compared to those of the controls. The activities of aldehyde oxidase (AO) and xanthine oxidase (XO) significantly (P<0.05) increased compared with the control. Conclusion The major effects of APWW on plants were stimulation of growth parameters, increase in concentration of macromolecules as well as increase in activities of starch-metabolizing enzymes, and peroxidase activity with no adverse effect on antioxidant, respiratory and drug-metabolizing enzymes, thus, suggesting that artificial pond wastewater has positive effect on cowpea seedlings and can act as organic fertilizer for cowpea cultivation.

Keywords

• Cowpea 
• Enzymes 
• Macromolecules 
• Pond 
• Wastewater