Effects of iron toxicity on growth four rice varieties highlighted some biochemical aspects in resistant variety

In the present study, effects of iron excess treatments (0, 250, 500 mg L-1) were evaluated in four rice varieties including Shafagh, Khazar, Hashemi and Sadri in pot condition. Afterward, effects of iron excess (10 and 250 mg l-1) were further investigated in the most resistant variety (Shafagh) in sand culture with Yoshida nutrient solution. This experiment was arranged as factorial in RCBD with three replications in greenhouse condition. The results of soil experiments indicated that 250 and 500 mg l-1 treatments of iron reduced plant growth and relative water content in all varieties. The highest and the lowest growth reduction under iron toxicity were observed in Khazar and Shafagh varieties, respectively. Iron accumulation in roots was higher in iron excess treatments in compare to shoots. The potassium concentration decreased in all varieties, however, the lowest decrease rate under stress condition was exhibited by Shafagh variety. The results of sand culture experiments of Shafagh variety indicated that oxidative stress due to 250 mg L-1 iron treatment caused reduction of chlorophyll content and consequently proteins, soluble sugar decreased probably by photosynthesis decline. Increase of amino acids content in plants fed with high iron supply is may be result lower protein synthesis or higher protein degradation.