A study was conducted to determine the physiological characteristics changes of Aesculus chinensis seeds during natural dehydration in 2003. The results showed that A. chinensis seeds were recalcitrant with being high...A study was conducted to determine the physiological characteristics changes of Aesculus chinensis seeds during natural dehydration in 2003. The results showed that A. chinensis seeds were recalcitrant with being highly desiccation-sensitive. The seed moisture content of fresh fruits was higher than 60%. When the seeds were naturally dried for 30 days, their moisture content declined to 30.2% and their viability was completely lost. The seed germination percentage had a small increase at the beginning of desiccation and then decreased rapidly. The relative electrical conductivity of the A. chinensis seeds increased along with a decrease in seed moisture content. However, there was an abnormal increase in relative electrical conductivity when the seed moisture content was between 53.7% and 50.9%. Superoxide dismutase （SOD） activity decreased rapidly in the period of desiccation except for an abnormality when the seed moisture content was between 53.7% and 50.9%. Malondialdehyde （MDA） content increased slowly at the early stage of desiccation and then rose rapidly after the moisture content was below 50.9%. The soluble sugar content in seeds slowly increased with the increasing period of desiccation. The seed germination percentage was at the high level when seed moisture content was in range of 47%- 60%, which suggests that this was the optimum moisture content for maintaining A. chinensis seed viability.展开更多
The antioxidant enzyme activity and malondialdehyde(MDA) content of Cephalothrix hongkongiensis were studied to assess variations in the biochemical/physiological parameters of nemerteans under heavy metal stress.Worm...The antioxidant enzyme activity and malondialdehyde(MDA) content of Cephalothrix hongkongiensis were studied to assess variations in the biochemical/physiological parameters of nemerteans under heavy metal stress.Worms were exposed to copper,zinc and cadmium solutions at different concentrations,and the activity of three antioxidant enzymes,catalase(CAT),superoxide dismutase(SOD),and glutathione peroxidase(GPX),and MDA content were measured.The results show that the activity of each enzyme changed immediately after exposure to heavy metals.CAT was invariably inhibited throughout the experimental period,while the SOD activity was significantly elevated by exposure to Cu^(2+) for 48h,but then decreased.SOD was inhibited by Zn^(2+) during the first 12h of exposure,but activated when exposed for longer periods.Under Cd^(2+) stress,SOD activity decreased within 72h.GPX activity varied greatly,being significantly increased by both Cu^(2+) and Zn^(2+),but significantly inhibited by Cd^(2+) in the first 12-24h after exposure.MDA content increased on Cu^(2+) exposure,but normally decreased on Zn^(2+) exposure.MDA content followed an increase-decrease-increase pattern under Cd^(2+) stress.In conclusion,the antioxidant system of this nemertean is sensitive to heavy metals,and its CAT activity may be a potential biomarker for monitoring heavy metal levels in the environment.展开更多
文摘A study was conducted to determine the physiological characteristics changes of Aesculus chinensis seeds during natural dehydration in 2003. The results showed that A. chinensis seeds were recalcitrant with being highly desiccation-sensitive. The seed moisture content of fresh fruits was higher than 60%. When the seeds were naturally dried for 30 days, their moisture content declined to 30.2% and their viability was completely lost. The seed germination percentage had a small increase at the beginning of desiccation and then decreased rapidly. The relative electrical conductivity of the A. chinensis seeds increased along with a decrease in seed moisture content. However, there was an abnormal increase in relative electrical conductivity when the seed moisture content was between 53.7% and 50.9%. Superoxide dismutase （SOD） activity decreased rapidly in the period of desiccation except for an abnormality when the seed moisture content was between 53.7% and 50.9%. Malondialdehyde （MDA） content increased slowly at the early stage of desiccation and then rose rapidly after the moisture content was below 50.9%. The soluble sugar content in seeds slowly increased with the increasing period of desiccation. The seed germination percentage was at the high level when seed moisture content was in range of 47%- 60%, which suggests that this was the optimum moisture content for maintaining A. chinensis seed viability.
基金Supported by the National Natural Science Foundation of China(No.30270235)
文摘The antioxidant enzyme activity and malondialdehyde(MDA) content of Cephalothrix hongkongiensis were studied to assess variations in the biochemical/physiological parameters of nemerteans under heavy metal stress.Worms were exposed to copper,zinc and cadmium solutions at different concentrations,and the activity of three antioxidant enzymes,catalase(CAT),superoxide dismutase(SOD),and glutathione peroxidase(GPX),and MDA content were measured.The results show that the activity of each enzyme changed immediately after exposure to heavy metals.CAT was invariably inhibited throughout the experimental period,while the SOD activity was significantly elevated by exposure to Cu^(2+) for 48h,but then decreased.SOD was inhibited by Zn^(2+) during the first 12h of exposure,but activated when exposed for longer periods.Under Cd^(2+) stress,SOD activity decreased within 72h.GPX activity varied greatly,being significantly increased by both Cu^(2+) and Zn^(2+),but significantly inhibited by Cd^(2+) in the first 12-24h after exposure.MDA content increased on Cu^(2+) exposure,but normally decreased on Zn^(2+) exposure.MDA content followed an increase-decrease-increase pattern under Cd^(2+) stress.In conclusion,the antioxidant system of this nemertean is sensitive to heavy metals,and its CAT activity may be a potential biomarker for monitoring heavy metal levels in the environment.
