Objective:The activity of enzymes participating in the systems of antioxidant protection was assayed in the peel and pulp of sunflower.The essential roles of proteases in food stimulate research to find other sources ...Objective:The activity of enzymes participating in the systems of antioxidant protection was assayed in the peel and pulp of sunflower.The essential roles of proteases in food stimulate research to find other sources of the enzyme especially from non-conventional sources.In the present work,we study several biochemical parameters in the pulp and peel of sunflower.Methods:Pulp and peel of sunflower was extracted,antioxidant enzymes and nonenzymatic antioxidant were measured.Alkaline protease was measured and purified from pulp in sunflower.Results:High carbohydrate concentration,beta-carotene,catalase and ascorbate peroxidase activities,free radical scavenging capacity and free flavonoid content were observed in the peel of sunflower.Whereas,MDA and ceruloplasmin activities were high in the pulp of sunflower.Conclusions:The present study concluded that peel in sunflower are strong radical scavengers and can be considered as good sources of natural antioxidants for medicinal and commercial uses.Further analysis showed that protease activity was a significantly high in the pulp compared to the peel.展开更多
It is a well-known fact that a mature seed can survive losing most of its water, yet how seeds acquire desiccation- tolerance is not well understood. Through sampling maize embryos of different developmental stages an...It is a well-known fact that a mature seed can survive losing most of its water, yet how seeds acquire desiccation- tolerance is not well understood. Through sampling maize embryos of different developmental stages and comparatively studying the integrity, oxygen consumption rate and activities of antioxidant enzymes in the mitochondria, the main origin site of reactive oxygen species （ROS） production in seed cells, we found that before an embryo achieves desiccation-tolerance, its mitochondria shows a more active metabolism, and might produce more ROS and therefore need a more effective ROS scavenging system. However, embryo dehydration in this developmental stage declined the activities of most main antioxidant enzymes and accumulated thiobarbituric acid-reactive products in mitochondria, and then destroyed the structure and functional integrity of mitochondria. In physiologically-matured embryos （dehydration- tolerant）, mitochondria showed lower metabolism levels, and no decline in ROS scavenging enzyme activities and less accumulation of thiobarbituric acid-reactive products after embryo dehydration. These data indicate that seed desiccation- tolerance acquisition might be associated with down-adjustment of the metabolism level in the late development stage, resulting in less ROS production, and ROS scavenging enzymes becoming desiccation-tolerant and then ensuring the structure and functional integrity of mitochondria.展开更多
A number of studies have shown the existence of cross-tolerance in plants, but the physiological mechanism is poorly understood. In this study, we used the germination of barley seeds as a system to investigate the cr...A number of studies have shown the existence of cross-tolerance in plants, but the physiological mechanism is poorly understood. In this study, we used the germination of barley seeds as a system to investigate the cross-tolerance of low-temperature pretreatment to high-temperature stress and the possible involvement of reactive oxygen species （ROS） scavenging enzymes in the cross-tolerance. After pretreatment at 0 ℃ for different periods of time, barley seeds were germinated at 35 ℃, and the content of malondialdehyde （MDA） and the activities of ROS scavenging enzymes were measured by a spectrophotometer analysis. The results showed that barley seed germinated very poorly at 35 ℃, and this inhibitive effect could be overcome by pretreatment at 0 ℃. The MDA content varied, depending on the temperature at which seeds germinated, while barley seeds pretreated at 0 ℃ did not change the MDA content. Compared with seeds germinated directly at 35 ℃, the seeds pretreated first at 0 ℃ and then germinated at 35 ℃ had markedly increased activities of superoxide dismutase （SOD）, ascorbate peroxidase （APX）, catalase （CAT）, and glutathione reductase （GR）. The SOD and APX activities of seeds germinated at 35 ℃ after 0 ℃-pretreatment were even substantially higher than those at 25 ℃, and GR activity was similar to that at 25 ℃, at which the highest germination performance of barley seeds was achieved. These results indicate that low-temperature pretreatment can markedly increase the tolerance of barley seed to high temperature during germination, this being related to the increase in ROS scavenging enzyme activity. This may provide a new method for increasing seed germination under stress environments, and may be an excellent model system for the study of cross-tolerance.展开更多
文摘Objective:The activity of enzymes participating in the systems of antioxidant protection was assayed in the peel and pulp of sunflower.The essential roles of proteases in food stimulate research to find other sources of the enzyme especially from non-conventional sources.In the present work,we study several biochemical parameters in the pulp and peel of sunflower.Methods:Pulp and peel of sunflower was extracted,antioxidant enzymes and nonenzymatic antioxidant were measured.Alkaline protease was measured and purified from pulp in sunflower.Results:High carbohydrate concentration,beta-carotene,catalase and ascorbate peroxidase activities,free radical scavenging capacity and free flavonoid content were observed in the peel of sunflower.Whereas,MDA and ceruloplasmin activities were high in the pulp of sunflower.Conclusions:The present study concluded that peel in sunflower are strong radical scavengers and can be considered as good sources of natural antioxidants for medicinal and commercial uses.Further analysis showed that protease activity was a significantly high in the pulp compared to the peel.
基金Supported by the Knowledge Innovation Program of the Chinese Academy of Sciences (KSCX2-YW-Z-058)the National Natural Science Foundation of China (3047018330870223)
文摘It is a well-known fact that a mature seed can survive losing most of its water, yet how seeds acquire desiccation- tolerance is not well understood. Through sampling maize embryos of different developmental stages and comparatively studying the integrity, oxygen consumption rate and activities of antioxidant enzymes in the mitochondria, the main origin site of reactive oxygen species （ROS） production in seed cells, we found that before an embryo achieves desiccation-tolerance, its mitochondria shows a more active metabolism, and might produce more ROS and therefore need a more effective ROS scavenging system. However, embryo dehydration in this developmental stage declined the activities of most main antioxidant enzymes and accumulated thiobarbituric acid-reactive products in mitochondria, and then destroyed the structure and functional integrity of mitochondria. In physiologically-matured embryos （dehydration- tolerant）, mitochondria showed lower metabolism levels, and no decline in ROS scavenging enzyme activities and less accumulation of thiobarbituric acid-reactive products after embryo dehydration. These data indicate that seed desiccation- tolerance acquisition might be associated with down-adjustment of the metabolism level in the late development stage, resulting in less ROS production, and ROS scavenging enzymes becoming desiccation-tolerant and then ensuring the structure and functional integrity of mitochondria.
基金Project (No. 30870223) supported by the National Natural Science Foundation of China
文摘A number of studies have shown the existence of cross-tolerance in plants, but the physiological mechanism is poorly understood. In this study, we used the germination of barley seeds as a system to investigate the cross-tolerance of low-temperature pretreatment to high-temperature stress and the possible involvement of reactive oxygen species （ROS） scavenging enzymes in the cross-tolerance. After pretreatment at 0 ℃ for different periods of time, barley seeds were germinated at 35 ℃, and the content of malondialdehyde （MDA） and the activities of ROS scavenging enzymes were measured by a spectrophotometer analysis. The results showed that barley seed germinated very poorly at 35 ℃, and this inhibitive effect could be overcome by pretreatment at 0 ℃. The MDA content varied, depending on the temperature at which seeds germinated, while barley seeds pretreated at 0 ℃ did not change the MDA content. Compared with seeds germinated directly at 35 ℃, the seeds pretreated first at 0 ℃ and then germinated at 35 ℃ had markedly increased activities of superoxide dismutase （SOD）, ascorbate peroxidase （APX）, catalase （CAT）, and glutathione reductase （GR）. The SOD and APX activities of seeds germinated at 35 ℃ after 0 ℃-pretreatment were even substantially higher than those at 25 ℃, and GR activity was similar to that at 25 ℃, at which the highest germination performance of barley seeds was achieved. These results indicate that low-temperature pretreatment can markedly increase the tolerance of barley seed to high temperature during germination, this being related to the increase in ROS scavenging enzyme activity. This may provide a new method for increasing seed germination under stress environments, and may be an excellent model system for the study of cross-tolerance.
