Phosphorus and Zinc Uptake and Their Interaction Effect on Dry Matter and Chlorophyll Content of Sweet Corn (Zea mays var. Saccharata)

Zinc and Phosphorus have antagonistic effect on the absorption and translocation of each other in plants. P-induced Zn deficiency is more common than Zn-induced P deficiency because growers commonly apply large amounts of P fertilizer as compared to Zn fertilizer. This research was conducted to examine the effect of different levels of Zn and P on the yield, Zn and P uptake and chlorophyll contents of corn plants. Sweet corn was grown in nutrient culture containing all combinations of Zn as ZnSO4.7H2O at levels of 0.0, 5.0, 10.0 and 20.0 mg L-1 and of P as KH2PO4 at levels of 0.0, 20.0, 40.0 and 80.0 mg L-1. Zn0P20 treatment produced the highest yield and the yields were decreased with P application in combination with Zn. The lowest dry weight of young corn plants was recorded under Zn0P80 treatment at both harvesting times due to both Zn deficiency and P toxicity. Chlorophyll content decreased with high Zn and P applications and this can be attributed to the interactions of Zn and P with iron in the growth medium. Zn0P80 treatment had the lowest Zn and the highest P uptake by shoot at 14 days after transplanting. The study has shown that Zn deficiency can enhance P uptake and translocation to such an extent that P may accumulate to toxic level in leaves. Zn20P80 treatment produced the highest Zn and P uptake by roots. Zn and P uptake by roots