Soil enzyme activity plays an important role in the conversion of soil organic carbon into inorganic carbon, which is significant for the global carbon cycle. In this study, we investigated the soil enzyme activities ...Soil enzyme activity plays an important role in the conversion of soil organic carbon into inorganic carbon, which is significant for the global carbon cycle. In this study, we investigated the soil enzyme activities of two ligninolytic enzymes （peroxidase and polyphenol oxidase） and five non-ligninolytic enzymes （a-l,4-glucosidase （AG）; 13-1,4-gluco- sidase （BG）; N-acetyl-[3-glucosaminidase （NAG）; ~3-D-cellobiosidase （CBH）; and ^-xylosidase （BXYL）） in four plant communities of the Sangong River basin in Fukang, North Xinjiang, China. The four typical plant communities were dominated by Haloxylon ammodendron, Reaumuria soongonica, Salsola passerina, and Tamarix rarmosissima, respec- tively, with saline soils of varied alkalinity. The results showed that the soil peroxidase activity decreased seasonally. The activities of the five non-ligninolytic enzymes decreased with increasing soil depths, while those of the two ligninolytic enzymes did not show such a trend. In the four plant communities, BG had the highest activity among the five non-ligninolytic enzymes, and the activities of the two ligninolytic enzymes were higher than those of the four non-ligninolytic ones （AG, NAG, CBH, and BXYL）. The community of H. ammodendron displayed the highest activity with respect to the two ligninolytic enzymes in most cases, but no significant differences were found among the four plant communities. The geometric mean of soil enzyme activities of the four plant communities was validated through an inde- pendently performed principal component analysis （PCA）, which indicated that different plant communities had different soil enzyme activities. The correlation analysis showed that soil polyphenol oxidase activity was significantly positively correlated with the activities of the five non-ligninolytic enzymes. The soil pH value was positively correlated with the ac- tivities of all soil enzymes except peroxidase. Soil microbial carbon content also showed a significant positive correlation （P〈0.01） with the activities of all soil enzymes except polyphenol oxidase. The results suggested that the H. ammoden- dron community has the highest ability to utilize soil organic carbon, and glucoside could be the most extensively utilized non-ligninolytic carbon source in the saline soil of arid areas in Xinjiang.展开更多
Reaumuria soongorica and Salsola passerina have significant differences in ecophysiological characteristics, which change with the environmental variations. Although they live together for a long period of time, their...Reaumuria soongorica and Salsola passerina have significant differences in ecophysiological characteristics, which change with the environmental variations. Although they live together for a long period of time, their adaptive mechanisms to environmental stresses are very different. As two extreme xerophytes, Reaumuria soongorica and Salsola passerina differ significantly from other psammophytes in ecophysiological characteristics; they can survive in lower water potential, and can even grow in piedmont areas. Low water potential may be related to the existence of osmosis-regulating substance, such as praline, which can strengthen the capacity of water absorption. Compared to other psammophytes, Reaumuria soongorica and Salsola passerina have a higher degree of photo-inhibition under the same condition, and the photo-inhibition can lead to destruction of the photosynthetic pigment, nevertheless, this photo-inhibition can be repaired under suitable conditions in the morning and evening.展开更多
基金Support Project of Gansu Province(0804NKCA075)Science & Technology Project of Lanzhou,Gansu Province(08-1-169)Science & Technology Base Project of Gansu Educational Bureau(08zd-14)
基金National Basic Research Program of China (2009CB825103)National Natural Science Foundation of China (31200422)China’s Postdoctoral Science Foundation (2012M520455, 2013T60193)
文摘Soil enzyme activity plays an important role in the conversion of soil organic carbon into inorganic carbon, which is significant for the global carbon cycle. In this study, we investigated the soil enzyme activities of two ligninolytic enzymes （peroxidase and polyphenol oxidase） and five non-ligninolytic enzymes （a-l,4-glucosidase （AG）; 13-1,4-gluco- sidase （BG）; N-acetyl-[3-glucosaminidase （NAG）; ~3-D-cellobiosidase （CBH）; and ^-xylosidase （BXYL）） in four plant communities of the Sangong River basin in Fukang, North Xinjiang, China. The four typical plant communities were dominated by Haloxylon ammodendron, Reaumuria soongonica, Salsola passerina, and Tamarix rarmosissima, respec- tively, with saline soils of varied alkalinity. The results showed that the soil peroxidase activity decreased seasonally. The activities of the five non-ligninolytic enzymes decreased with increasing soil depths, while those of the two ligninolytic enzymes did not show such a trend. In the four plant communities, BG had the highest activity among the five non-ligninolytic enzymes, and the activities of the two ligninolytic enzymes were higher than those of the four non-ligninolytic ones （AG, NAG, CBH, and BXYL）. The community of H. ammodendron displayed the highest activity with respect to the two ligninolytic enzymes in most cases, but no significant differences were found among the four plant communities. The geometric mean of soil enzyme activities of the four plant communities was validated through an inde- pendently performed principal component analysis （PCA）, which indicated that different plant communities had different soil enzyme activities. The correlation analysis showed that soil polyphenol oxidase activity was significantly positively correlated with the activities of the five non-ligninolytic enzymes. The soil pH value was positively correlated with the ac- tivities of all soil enzymes except peroxidase. Soil microbial carbon content also showed a significant positive correlation （P〈0.01） with the activities of all soil enzymes except polyphenol oxidase. The results suggested that the H. ammoden- dron community has the highest ability to utilize soil organic carbon, and glucoside could be the most extensively utilized non-ligninolytic carbon source in the saline soil of arid areas in Xinjiang.
基金supported by the National Natural Science Foundation of China (No. 30870383 and No. 30740051)the National Key Technology R&D Program of China(No. 2007BAD54B05 and No. 2008BAC39B04)
文摘Reaumuria soongorica and Salsola passerina have significant differences in ecophysiological characteristics, which change with the environmental variations. Although they live together for a long period of time, their adaptive mechanisms to environmental stresses are very different. As two extreme xerophytes, Reaumuria soongorica and Salsola passerina differ significantly from other psammophytes in ecophysiological characteristics; they can survive in lower water potential, and can even grow in piedmont areas. Low water potential may be related to the existence of osmosis-regulating substance, such as praline, which can strengthen the capacity of water absorption. Compared to other psammophytes, Reaumuria soongorica and Salsola passerina have a higher degree of photo-inhibition under the same condition, and the photo-inhibition can lead to destruction of the photosynthetic pigment, nevertheless, this photo-inhibition can be repaired under suitable conditions in the morning and evening.
