Changes in the roots of sunflower under iron stress

Abstract

Growth and physiological changes in sunflower (Helianthus annus L. cv. Northrup King 265) were observed when plants were grown at selected concentrations of iron in solution. Plant roots were tested for reduction capacity with tetrazolium (2,3,5‐triphenyl‐tetrazolium chloride). Iron stressed roots indicated very high capacities for reduction. The amount of reduction was quantified and expressed as amount of tetrazolium reduced per gram of root fresh weight. Root respiration levels were monitored using an oxygen electrode. Iron stressed roots consumed more oxygen than nonstressed roots.

Key words:

• Sunflower
• Iron stress response
• Root oxygen consumption
• Reducing activity
• Iron chlorosis