Night blooming jessamine (Cestrum nocturnum L.) plants were grown in pots to study P-Zn interactionwhich influence on their accumulations and other micronutrients in leaf tissue. Phosphorus fertilization was applied to soil at rates of 0 to 580 ppm with concomitant addition of Zn at rates of 0 to 48 ppm.
Concentrations of Zn, Fe and Mn in leaf tissue indicated that P and Zn fertilization had altered the accumulation of these micronutrients in the plant. Although P and Zn application decreased the concentration of each other, increasing either P or Zn applied increased leaf Mn. Concentrations of P, Zn and Mn were varied opposite to that of Fe. Zinc-deficient plants accumulated a large excess of Fe. Interference from excess Fe is suggested as contributing to physiological malfunction within Zn-deficient night-blooming jessamine plants. High concentration of P in leaf tissue resulting in high P/Zn concentration ratios appear to offer a better explanation for the metabolic upset. Healthy plants tended to have P/Zn concentration ratios < 100, where in deficient plants the ratio was generally > 100.
Some of the resulting observations help to explain why starter fertilizers containing P may on occasions cause depressions in plant growth, especially when soil P is high, would seem to portend Zn deficiency problems as the behavior of both P and Zn in affecting translocation of each other.