MAIZE HYBRIDS DIFFER IN THEIR 24-H PATTERNS OF PHYTOSIDEROPHORE RELEASE

Abstract

Iron (Fe) chlorosis tolerant gramineous species respond to Fe-deficiency stress by releasing phytosiderophores. The objective of this study was to characterize the diurnal pattern of phytosiderophore release from Fe-chlorosis tolerant and susceptible maize (Zea mays L.) hybrids. Phytosiderophore was collected from individual, Fe-deficient maize plants in 10 mg L⁻¹ Micropur solution during 4-h collection periods. The diurnal pattern of phytosiderophore release differed among maize hybrids. Similar levels of phytosiderophore were released during light and dark conditions for three hybrids. Greater phytosiderophore release was measured from a fourth hybrid when the collection procedure began 2-h after the initiation of light compared to 2-h before the initiation of dark. When a single plant was used for six consecutive collection periods, phytosiderophore release declined during the final 8- to 12-h of collection. The decline in phytosiderophore release was attributed to dissolution of apoplastic Fe and deactivation of the Fe-stress response mechanism.

Keywords:

• corn
• maize
• iron-deficiency stress
• diurnal phytosiderophore release
• mugineic acid

ACKNOWLEDGMENTS

We appreciate the technical assistance that was provided by Ben Hubbard, Dianne Carter, Jake Thompson, Eliseu Mann, and Jared Williams in conducting this research.