Iron Deficiency Stimulated Some Enzymes Activity, Lipid Peroxidation and Free Radicals Production in Borage officinalis Induced in vitro

Iron deficiency is one of the most important factors affecting growth and yield. Utilizing tissue culture technique to study the response of plant to Fe-stress was suggested as a rapid and simple method. Fe-deficiency was explored by cultivating shoots of Borage plantlets on MS media with 27.8, 13.0, 0.0 mg/L FeSO4. Results showed that, severe Fe-deficiency induced yellowing and typical iron deficiency symptoms. Chlorophyll was also inhibited. The response of antioxidant enzymes, such as catalase (CAT) and ascorbate peroxidase (APX) to iron stress was also examined. CAT and APX activities declined by 49.3% and 56.6% in young Fe-deficient leaves respectively. Whereas the content of glutathione increased by 28.9% compared to control treatment. Enhancement in lipid peroxidation was also more evident under severe Fe-deficiency. Iron stress also induced several changes in CAT and peroxidase (POD) isozyme profiles and enhanced their activities, especially those of POD. Using electron spin resonance (ESR) showed that, severe Fe-deficiency markedly increased level of free radicals formation.