Changing effluent chemistry affect survival, growth and physiological function of Acacia nilotica seedlings in northwestern region of India

Abstract

Recycling and conservation efforts for water are the need of the day because of the lack of new water sources and the ever-increasing demand for drinking water. Seedlings of Acacia nilotica L. were irrigated with: canal water (T 1 , control); municipal effluent (T 2 ); textile effluent (T 3 ); steel effluent (T 4 ); textile + municipal effluent in 1:1 ratio (T 5 ); steel + municipal effluent in 1:2 ratio (T 6 ); steel + textile in 1:2 ratio (T 8 ) and steel + municipal + textile in 1:2:2 ratio (T 7 ) with views to observe effluents effect on the seedlings and its adaptability and to recommend safe disposal of these effluents. Seedlings in T 6 , T 7 and T 8 showed 50% lesser height and collar diameter than those in control. Seedlings in T 2 attained greatest height, collar diameter, numbers of branches and produced 140 g dry biomass seedling -1 . Highest concentration of manganese (Mn), iron (Fe), copper (Cu) and zinc (Zn) and lowest concentration of nitrogen (N), phosphorus (P), potassium (K), calcium (Ca) and magnesium (Mg) in the seedlings of T 4 , T 6 , T 7 and T 8 resulted in nutritional imbalance, mineral toxicity and reduction in photosynthetic (Pn) and transpiration (E) rates and caused seedling mortality. Seedlings of T 3 had highest sodium concentration and low concentration of Ca, Mg and micronutrients resulting in nutritional imbalance, augmented chlorosis and reduced gas exchange and biomass by half as compared to control. Increased growth, Pn and E and biomass in seedlings of T 5 over T 3 and survival period in T 6 , T 7 and T 8 seedlings suggested a beneficial effect of effluents mixing. Unscientific disposal should be avoided and toxic concentration of metal ions may be reduced for long-term application and harmless disposal of effluents in afforestation and urban development.

Physiological Responses to Nutrient Accumulation in Trees Seedlings Irrigated with Municipal Effluent in Indian Desert

“…Linear/nonlinear increase in with nutrient concentrations suggests a close link of photosynthetic capacity with nutrient supply, but simultaneous increases in and s ( Figure 5) are indicative of rapid growth and biomass production [45]. A decline/saturation, after an initial increase in and with increase in concentrations of Ca, Na, and Fe, was as a result of the effects of accumulated minerals and limitations due to other nutrients and their ratios [45,46]. A reduction in net photosynthetic rate and stomatal conductance due to a toxic effect of Na + has also been reported in Citrus limonia Osbeck and Olea europaea L. [47].…”