Effects of Iron Excess on Nicotiana plumbaginifolia Plants (Implications to Oxidative Stress)

摘要: Fe excess is believed to generate oxidative stress. To contribute the understanding of metabolism, was induced in Nicotiana plumbaginifolia grown hydroponic culture upon root cutting. Toxicity symptoms leading brown spots covering leaf surface became visible after 6 h. Photosynthesis greatly affected within 12 h; photosynthetic rate decreased by 40%. Inhibition photosynthesis accompanied photoinhibition, increased reduction photosystem II, and higher thylakoid energization. seemed stimulate photorespiration because catalase activity doubled. cope with cellular damage, respiration cytosolic glucose-6-phosphate dehydrogenase more than Simultaneously, content free hexoses reduced. Indicative generation stress doubling ascorbate peroxidase Contents antioxidants glutathione were reduced 30%, resulting equivalent increases dehydroascorbate oxidized glutathione. Taken together, moderate changes have a dramatic effect on plant metabolism. This indicates that concentrations must be finely regulated avoid damage most probably Fe.