In the present experiment, wheat seedlings (Trticucum aestivum L.) were grown on a purple soil withvarious fertilizer treatments in order to investigate the responses of nitrogen and related eusyme activitiesin the rh...In the present experiment, wheat seedlings (Trticucum aestivum L.) were grown on a purple soil withvarious fertilizer treatments in order to investigate the responses of nitrogen and related eusyme activitiesin the rhizosphere. The results revealed the increments of both organic matter and total N in the soil withthe proximity to the growing roots, especially in the treatment of supplying pig manure in combination withchemical fertilizer, suggesting that they could come from root and microorganism exudation which could beintensified by inorganic-organic fertilization, being of benefit to improving the physical and biological envi-ronment in the rhizosphere of wheat. Much more inorganic N was observed in the fertilized soils surroundingwheat roots than in the CK treatment, indicating the improvement of crop N supply in the rhisosphere ofwheat by fertilization.The activities of invertase, urease and protease in the root zone were greatly enhanced as compared tothose in the other parts of soils except that the urease activities were similar in the rhizo8phere and nonrhi-zosphere of the CK and pig manure treatments, indicating that invertase and protease could be produced bygrowing roots and rhizosphere microorganisms, in contrast to urease which could be stimulated by urea. Also,significant increment of these three enzyme activities in the rhizosphere of wheat by fertilizatioll, especially byapplication of chemical fertilizer combined with pig manurel suggested that fertilization not only acceleratedthe renewal of organic matter but also enhanced bioavailability of organic N in that soil zone. This couldbe the reason why the total amount of inorganic N available for plants was increased more obviously in therhizosphere of wheat of the fertilization treatments than in that of the CK treatment.展开更多
In the traditional Intemet Protocol （IP） architecture, there is an overload of IP sermntic problems. Existing solutions focused mainly on the infrastructure for the fixed network, and there is a lack of support for ...In the traditional Intemet Protocol （IP） architecture, there is an overload of IP sermntic problems. Existing solutions focused mainly on the infrastructure for the fixed network, and there is a lack of support for Mobile Ad Hoc Networks （MANETs）. To improve scalability, a routing protocol for MANETs is presented based on a locator named Tree-structure Locator Distance Vector （TLDV）. The hard core of this routing method is the identifier/locator split by the Distributed Hash Table （DHT） method, which provides a scalable routing service. The node locator indicates its relative location in the network and should be updated whenever topology changes, kocator space ks organized as a tree-structure, and the basic routing operation of the TLDV protocol is presented. TLDV protocol is compared to some classical routing protocols for MANETs on the NS2 platform Results show that TLDV has better scalability. Key words：展开更多
文摘In the present experiment, wheat seedlings (Trticucum aestivum L.) were grown on a purple soil withvarious fertilizer treatments in order to investigate the responses of nitrogen and related eusyme activitiesin the rhizosphere. The results revealed the increments of both organic matter and total N in the soil withthe proximity to the growing roots, especially in the treatment of supplying pig manure in combination withchemical fertilizer, suggesting that they could come from root and microorganism exudation which could beintensified by inorganic-organic fertilization, being of benefit to improving the physical and biological envi-ronment in the rhizosphere of wheat. Much more inorganic N was observed in the fertilized soils surroundingwheat roots than in the CK treatment, indicating the improvement of crop N supply in the rhisosphere ofwheat by fertilization.The activities of invertase, urease and protease in the root zone were greatly enhanced as compared tothose in the other parts of soils except that the urease activities were similar in the rhizo8phere and nonrhi-zosphere of the CK and pig manure treatments, indicating that invertase and protease could be produced bygrowing roots and rhizosphere microorganisms, in contrast to urease which could be stimulated by urea. Also,significant increment of these three enzyme activities in the rhizosphere of wheat by fertilizatioll, especially byapplication of chemical fertilizer combined with pig manurel suggested that fertilization not only acceleratedthe renewal of organic matter but also enhanced bioavailability of organic N in that soil zone. This couldbe the reason why the total amount of inorganic N available for plants was increased more obviously in therhizosphere of wheat of the fertilization treatments than in that of the CK treatment.
基金Acknowledgements This work was supported by the Hi-Tech Research and Development Program of China under Grant No.2007AA01Z407 the Co-Funding Project of Beijing Municipal education Commission under Grant No.JD100060630+3 种基金 National Foundation Research Project the National Natural Science Foundation Project under Grant No. 61170295 the Project of Aeronautical Science Foundation of China under Caant No.2011ZC51024 and the Fundamental Research Funds for the Central Universities.
文摘In the traditional Intemet Protocol （IP） architecture, there is an overload of IP sermntic problems. Existing solutions focused mainly on the infrastructure for the fixed network, and there is a lack of support for Mobile Ad Hoc Networks （MANETs）. To improve scalability, a routing protocol for MANETs is presented based on a locator named Tree-structure Locator Distance Vector （TLDV）. The hard core of this routing method is the identifier/locator split by the Distributed Hash Table （DHT） method, which provides a scalable routing service. The node locator indicates its relative location in the network and should be updated whenever topology changes, kocator space ks organized as a tree-structure, and the basic routing operation of the TLDV protocol is presented. TLDV protocol is compared to some classical routing protocols for MANETs on the NS2 platform Results show that TLDV has better scalability. Key words：
