Anion proportion in the nutrient solution impacts the growth and nutrient status of anthurium (Anthurium andraeanum Linden ex. André.)

Abstract

Anthurium is native to habitats characterized by low nutrient supply; however, when cultivated, it demands a complete fertilization program. The objective of the present study was to determine the effect of varying proportions of anions [nitrate (NO3-), phosphate (H2PO4-), and sulphate (SO42-)] in the nutrient solution on the growth and nutrient status of container-grown anthurium. The effect of the anion proportion was modeled using mixture analysis. Plant growth increased when fertigated with solutions containing an anion proportion of 0.78:0.12:0.10, 0.20:0.12:0.68, and 0.80:0.02:0.18. The contour plots showed that optimum response may be achieved in two areas, an area with high NO3 L proportion (0.50-0.80) and an area with high SO4-, provided H2PO4- was high (0.09-0.12 for H2PO4- and 0.55-0.70 for SO42-). The counter plots indicate that high SO42- proportions combined with low NO3- andH2PO4- were detrimental and that optimum growth depends not only on nitrogen (N) concentration, as it may be attained at either high or low NO3-. Nitrogen and sulfur (S) concentrationwas higher in plants fertigated with highNO3- (0.55-0.80) and SO42- (0.40-0.70) solutions. Shoot P was higher when plants were fertigated with solutions of low (as long as NO3- was at proportion of 0.50 and SO42- at 0.35) or high H2PO4- proportions (as long as SO42- proportion was at 0.35). At low concentration of S in the shoot, increasing S resulted in increasing shoot N; however, further S increments in the shoot were associated with a decrease in N. Plants fertigated with the highest proportion of H2PO4- resulted in the lowest S concentrations despite some solutions contained high SO42-, suggesting thatH2PO4- counteracted the uptake of SO42-.Nitrogen and Swere predominantly diverted to the roots in control plants; however, when plants were fed with both high SO42- and high H2PO4- solutions, even more S was allocated to the roots, which explains the increased shoot growth due to the lower S concentrations. In conclusion, the increased growth of anthurium was attained at either high or low NO3- proportion and it is able to cope with high SO42- by avoiding the transport of S to the shoot, decreasing SO42- intake, maintaining a favorable internal N/S and S/P proportion, and increasing P tissue concentration.