Effects of Drought Stress on Physiological and Biochemical Characteristics and Saponins Content of Panax notoginseng
[Objective]The physiological and biochemical characteristics and saponins content change of Panax notoginseng under drought stress were explored,which provided the scientific basis for formulating drought resistant cultivation techniques for P.notoginseng.[Method]The physiological and biochemical indexes of roots,stems and leaves of P.notoginseng seedlings(60 days old)and saponin contents were studied by simulating drought stress with different concentrations(2.5%,5.0% and 7.5% )of PEG 6000 solution.[Result]The content of Pro,POD,APX and MDA content in leaves and roots of P.notoginseng showed significant changes under different concentrations of PEG 6000 drought stress.With the increase of PEG 6000 concentration and the prolongation of treatment time,the content of Pro,POD,APX and MDA in leaves and roots gradually increased.When PEG 6000 was treated with 7.5% for 7 days,the Pro content in leaves and roots was 0.62 mg/g and 0.53 mg/g,respectively,which was 0.33 mg/g and 0.41 mg/g higher than that in CK(spaying distilled water).The POD content was 461.08 U/g and 210.76 U/g,which was 64.37 U/g and 137.55 U/g higher than CK,respectively.The APX content was 120.37 U/g and 54.46 U/g,respectively,which was 68.54 U/g and 49.85 U/g higher than that of CK.The MDA content was 27.09 μmol/g and 22.66 μmol/g,which was 23.93 μmol/g and 19.68 μmol/g higher than CK,respectively.The content of Pro,APX and MDA in stems showed no significant difference under different concentrations of PEG 6000 drought stress,and POD content in stems was undetected.The SOD content in roots and leaves showed a first increasing and then decreasing trend with the increase of PEG 6000 concentration,at the same treatment time(1 day,3 days,5 days and 7 days),SOD content in leaves treated with 5.0% PEG 6000 was the highest(272.06 U/g,413.29 U/g,458.86 U/g and 477.25 U/g),which was higher than that at other concentrations.The SOD content in root treated with 5.0% PEG 6000 was the highest(244.89 U/g,352.46 U/g,389.15 U/g and 405.61 U/g),which was higher than that at other concentration.The SOD content in stems was undetected.The CAT content in roots gradually increased with the increase of PEG 6000 concentration and time,CAT content in root was 103.43 U/g under 7.5% PEG 6000 treated for 7 days,which was higher than that at other concentrations.The CAT content in leaves showed a first increasing and then decreasing trend with the extension of time under the same concentration.The CAT content in leaves reached the maximum when treated for 3 days at the same concentration.CAT content of 2.5%,5.0% and 7.5% PEG 6000 was 348.05 U/g,425.98 U/g and 531.52 U/g,respectively.But the CAT content in stems had not significant difference.The saponin content in roots of P.notoginseng showed a first increasing and then decreasing trend with the increase of PEG 6000 concentration.After 7 days of treatment,the saponin content treated with 5.0% PEG 6000 was the highest,and the saponin content decreased when the concentration continued to increase.The chlorophyll content in leaves of P.notoginseng was significantly affected by different concentrations of PEG 6000.With the increase of PEG 6000 concentration,the accumulation of chlorophyll a,chlorophyll b and total chlorophyll in leaves gradually increased,after 7 days of treatment,the contents of chlorophyll a,chlorophyll b and total chlorophyll at 7.5% PEG 6000 were 4.16 mg/g,2.43 mg/g and 6.59 mg/g,respectively,which were higher than those at other concentrations.[Conclusion]The drought stress has a significant impact on the physiological and biochemical characteristics and saponin accumulation of P.notoginseng.Simultaneously,P.notoginseng can respond to drought stress by regulating its antioxidant enzyme system and increasing chlorophyll content,and then improve its own drought resistance ability.
Panax notoginsengPEG 6000drought stressphysiological and biochemical characteristicssapon-insenzyme activitychlorophyll
万方数据
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