Trace metal interactions in corn inbreds differing in efficiency of Mg uptake

Abstract

The Mg‐efficient corn (Zea mays L.) inbred B57 and the Mg‐inefficient inbred Oh40B were grown in solution culture with moderate levels of some trace metals to test their relative interactions since previous studies had indicated that excess trace metals may be part of the Mg‐inefficient syndrome. At the levels used only Co depressed yields and that for the Mg‐inefficient inbred only. Distribution of minerals in the plants was mostly as reported in the literature. At both a high and low level of Mg, Mg concentration was lower in the shoots of the Mg‐inefficient inbred than in the efficient one. In roots the reverse held especially at the low Mg level. The P concentration was higher in both roots and shoots of the inefficient inbred. The Zn was always higher in the inefficient inbred and this was more pronounced for roots than for shoots. Such effects with Mn were even more pronounced. Where extra Cu was supplied less was associated with roots of the inefficient inbred than with the efficient. When Ni was supplied it was distributed somewhat similarly. More K was in both shoots and roots of the inefficient inbred than in the efficient one. The reverse held for Ca in roots only. But at the high Mg level Oh40B shoots had more Ca than did B57 shoots. The low level of Mg resulted in more Ca in both roots and shoots of both inbreds but the increase in roots was far greater for the efficient inbred than for the inefficient inbred. Mg deficiency symptoms appeared only on the Oh40B inbred and iron chlorosis appeared on the Mg‐inefficient inbred with Zn, Cu, and Ni additions but on the Mg efficient inbred only with Cu addition.

Key words:

• Mg efficiency
• mineral stress
• zinc
• cobalt
• nickel
• manganese
• iron chlorosis