Effects of Application of Nitric Oxide on Respiration and Reactive Oxygen Metabolism in Leaves of Tobacoo under Aluminum Stress

LIU Qiang; LIU Zhengwei; HU Cui; JI Kangning

doi:10.15933/j.cnki.1004-3268.2017.01.008

Abstract：Two different aluminum (Al)-tolerant tobacoo cultivars Yunyan 100 (Al-tolerant) and Yunyan 105 (Al-sensitive) were used to study the effects of sodium nitroprusside(SNP,an exogenous NO donor) on plant growth,leaf reactive oxygen content and respiration,activities of antioxidant enzymes in mitochondria under Al stress using solution culture method,so as to find out exogenous NO-increased Al resistant mechanisms in tobacoo.The results showed that Al dramatically decreased leaf total respiration rate,cytochrome respiration rate,alternative respiration rate,cytochrome oxidase (COX) activity and pyruvate content,leading to the increase of leaf O2-· producing rate and H2O2 accumulation,and decrease of plant biomass,the variable amplitude in Yunyan 105 was bigger than that in Yunyan 100.Under Al stress,application of exogenous NO alleviated Al-induced inhibition of plant biomass,increased leaf total respiration rate,cytochrome respiration rate,alternative respiration rate,COX activity and pyruvate content,decreased leaf O2-· producing rate and H2O2 content,the alleviating effect was more significantly in Yunyan 105 than that in Yunyan 100.Furthermore,application of exogenous NO also increased activities of superoxide dismutase(SOD) and ascobate peroxidase(APX) in mitochondria,the increase amplitude was more significantly in Yunyan 105 than that in Yunyan 100 under Al stress.Therefore,the application of exogenous NO could alleviate Al phytotoxicity in tobacoo mainly by enhancing leaf respiration and activities of SOD and APX in mitochondria,which eliminated ROS in mitochondria,and the alleviating effect was greater in the Al-sensitive genotype than that in the Al-tolerant genotype.