RESUMO
ObjectiveTo investigate the effect of exogenous H2O2 on secondary metabolism in Atractylodes chinensis and its mechanism. MethodFresh rhizomes of A. chinensis were treated with 5.0， 1.0， 0.2， 0.04 mmol·L-1 H2O2 solution and clean water， and the relationships between the contents of reactive oxygen species， activities of antioxidant enzymes， activities of key enzymes of secondary metabolites， and contents of secondary metabolites in A. chinensis were compared. ResultUnder treatment with exogenous H2O2， the content of reactive oxygen species and malondialdehyde （MDA） in the fresh rhizomes of A. chinensis were significantly elevated on the 4th day， and returned to normal level on the 6th-8th day. The activities of superoxide dismutase （SOD）， catalase （CAT） and peroxidase （POD） were all increased first and then decreased， and reached the peak on the 4th， 4th-6th and 2th-4th day， respectively. The activities of 3-hydroxy-3-methyl glutaryl coenzyme A reductase （HMGR） and acetyl CoA carboxylase （ACC）， key enzymes of the secondary metabolites， were remarkably enhanced， and under treatments with different concentrations of H2O2， the activities of key synthetic enzymes of the secondary metabolites in 0.2 mmol·L-1 H2O2 group were increased most， with the highest biosynthesis of secondary metabolites. The contents of atractylodin， β-eudesmol， atractylone， atractylenolide Ⅱ， and atractylenolide Ⅲ on the 6th day of 0.2 mmol·L-1 H2O2 treatment were 89.5%， 108.7%， 308.8%， 64.7% and 9.3%， respectively higher than those in the control. ConclusionThe antioxidant enzymes and secondary metabolites in A. chinensis synergistically maintain the balance of reactive oxygen species， and exogenous H2O2 can improve the medicinal quality of A. chinensis remarkably.
RESUMO
ObjectiveTo explore the biological mechanism of drought improving the quality of Rhizoma Atractylodis Chinensis and establish a new method for the production of high-quality medicinal materials. MethodThe fresh roots of Atractylodes chinensis were soaked in 0 （control）， 5%， 10%， and 20% PEG-6000 solutions. The changes in reactive oxygen species （ROS） level， antioxidant enzyme activity， activities of key enzymes in primary metabolism and secondary metabolism， and content of secondary metabolites were compared. ResultCompared with the control group， the treatment with 20% PEG for 2 days elevated the levels of superoxide anion radicals （O2-·）， hydrogen peroxide （H2O2）， and malondialdehyde （MDA） by 172.5%， 56.9%， and 14.7%， respectively. The treatment did not change the activity of superoxide dismutase （SOD）， reduced the peroxidase （POD） activity， and increased the catalase （CAT） activity by 10.8%. It increased the activities of 3-hydroxy-3-methylglutaryl-CoA reductase （HMGR）， phosphoenolpyruvate carboxylase （PEPC）， and acetyl-CoA carboxylase （ACC） by 49.9%， 12.1%， and 19.0%， respectively. Furthermore， the content of atractylodin， β-eudesmol， atractylone， and atractylenolide Ⅱ was increased by 51.0%， 36.9%， 47.1%， and 91.5%， respectively. The simulated drought stress can cause the burst of ROS in the fresh roots of A. chinensis， induce the physiological state of plants under drought， change the antioxidant system， and promote the massive synthesis of secondary metabolites in a short time. ConclusionPEG-6000-simulated drought stress can greatly improve the quality of A. chinensis in cultivation.