Abstract:The relationship between Fe++-induced bronzing and stress ethylene production (SEP)was investigated both in detached rice (Oryza sativa L.)leaves and in whole plants.Fe++ was applied to the detached leaf through a transpiration stream and to whole plants through roots in culture solution.The SEP from detached leaves differed with leaf position,growth stage, and genotype.Correlation between SEP and bronzing was significant for the leaves of 16 tested genotypes(r=0.659**),but the iron concentration increment(ICI)of the detached leaf correlated neither to the bronzing nor to the SEP, suggesting that leaf tissue tolerance, not ICI, controls the bronzing deveiopment and the SEP.When the Whole plant was treated by increasing Fe++ concentration in culture solution,the SEP was negligibly small. By partially or entirely de-rooting the plant, however,stress ethylene was evoked bythe Fe++ treatment,indicating that roots limited the Fe++-induced SEP.
