Zinc Accumulation and Growth of Corn Seedlings as Affected by Endosperm Removal1

Abstract

AbstractPrevious work indicated that under low light intensity, seed Zn was the main source for young corn (Zea mays L.) seedlings and that uptake of Zn from an external source was minimal. Experiments were conducted under controlled conditions to determine the effects of endosperm removal on uptake and accumulation of Zn by corn seedlings under varying conditions of light intensity, P levels, and external Zn levels.Corn seedlings were grown three days at light intensities of 30,000 and 14,000 lux. The endosperm was removed from one group of seedlings and left intact on another group of seedlings. Three days later the seedlings were placed in Zn solutions of 0, 0.2, and 1.0 μM ZnSO and either 0 or 0.1 mM P. The uptake of Zn was investigated over a 144 hour uptake period. Endosperm removal did not affect Zn accumulation at the high light intensity. At the low light intensity, Zn accumulation was reduced by endosperm removal at 0.2 μM Zn, but accumulation was similar in both endosperm treatments at 1.0 μM Zn. Root growth was reduced more severely than top growth by endosperm removal at both light intensities as indicated by increasing shoot‐to‐root ratio. This effect was still apparent 216 hours after endosperm removal.Phosphorus treatments did not adversely affect Zn uptake or translocation. The maximum enhancement in Zn uptake was observed when P occurred as an external ion at low Zn concentration and minus endosperm treatment. At low light intensity Zn uptake rate was drastically reduced when P was not present as an external ion.