Concentration of NaCl as It Affects Emergence, Early Growth, and Nutrient Composition of Amaranthus

摘要

Amaranthus (Amaranthus tricolor L.) is cultivated in semi-arid parts of northern Nigeria where problems of drought and soil salinity are present. Information is lacking on how the plant responds to concentrations of salinity. The effect of NaCl salinity on emergence, early growth and plant nutrient concentrations of amaranthus was evaluated outdoors in a pot experiment, under a protective structure. Four salinity levels: 0.0, 5.08, 8.83, and 13.54 dS·m-1 were imposed with three replications. Time to emergence was delayed by up to 5 and 7 days at medium (ECe = 8.83 dS·m-1) and high (ECe = 13.54 dS·m-1) salinity levels, respectively, relative to the control. An increase in salinity levels resulted in reduction of plant height, leaf area, fresh and dry shoot weights and root weights. Salt concentration had both stimulatory and inhibitory effects on shoot and root nutrient concentrations. Increases in salinity to ECe = ≥5.08 dS·m-1 resulted in an increase in the shoot content of P, K, Ca, Na, and Cl and decreased those of N and Mg. The trend in changes in root nutrient content due to NaCl stress was similar to that of the shoot. Reductions in growth of plants receiving salt relative to the controls could be attributed to possible disruption of metabolic processes from unbalanced absorption, and possibly utilization of essential plant nutrients. Results need to be validated under field conditions.