Effects of boron on the physiological activity of zinc in maize

Abstract

When maize plants were grown in pots in a glasshouse for 30 days on a black earth soil, plants developed symptoms of zinc deficiency and responded to zinc fertilization, yet the tops contained normal levels of zinc. It was assumed that much of the zinc accumulated in plant tops was physiologically inactive.

The condition was not caused by phosphorus/zinc, iron/zinc, copper/zinc, or manganese/zinc imbalances, but was associated with marginally deficient boron levels in experiments conducted in late autumn when light intensity was low. In one such experiment, boron fertilization (1 µg/g) prevented the inactivation of zinc and increased plant growth.

However, in experiments conducted in spring when light intensity approximated the normal field situation more closely, boron levels were normal and boron fertilization (5 µg/g) had no effect on plant growth and failed to prevent zinc inactivation. Thus, it is unlikely that zinc inactivation under normal field conditions is caused by marginally deficient boron levels.