The vegetation and soil are mutual environmental factors, soil characteristics, such as chemical properties and microorganism that affect the vegetation occurrence, development and succession speed. In this study, we ...The vegetation and soil are mutual environmental factors, soil characteristics, such as chemical properties and microorganism that affect the vegetation occurrence, development and succession speed. In this study, we evaluated the structure of microbial communities of rhizosphere of Cowskin Azalea(Rhododendron aureum Georgi) populations and compared with non-rhizosphere soils at four sample sites of the Changbai Mountains, China, and analyzed the correlation between chemical properties of soil and microbial communities. The results showed that microbial structure and soil chemical properties are significant superior to non-rhizosphere at all four sample sites. The rhizosphere microorganisms are mainly composed of bacteria, actinomycetes, followed by fungi least. The principal component analysis(PCA) biplot displayed that there are differences between rhizosphere and non-rhizosphere soils for microflora; Through correlation analysis, we found that the bacteria is clearly influenced by p H on the Changbai Mountains, besides p H, other soil features such as NO3–-N. These data highlight that R. aureum as the dominant vegetation living in the alpine tundra is a key factor in the formation of soil microorganism and improving soil fertility, and is of great significance for the maintenance of alpine tundra ecosystem.展开更多
In Europe, eggs of the Common Cuckoo (Cuculus canorus) have been found in more than 125 different host species. However, very few species are frequently parasitized. The Cuckoo is divided into several distinct races t...In Europe, eggs of the Common Cuckoo (Cuculus canorus) have been found in more than 125 different host species. However, very few species are frequently parasitized. The Cuckoo is divided into several distinct races termed gentes. Females of each gens specialize in parasitizing a particular host species. More than 20 such gentes are recognized in Europe. Each female Cuckoo lays eggs of constant appearance. Most gentes can be separated based on their distinct egg types, which in many cases mimic those of their hosts. Different gentes may occur in sympatry or may be separated geographically. Some gentes may occur in restricted parts of the host’s distribution area. These patterns raise some fundamental questions like: Why are some passerine species preferred as hosts while others are not? Why does a host population consist of individuals either accepting or rejecting Cuckoo eggs? Why is there marked variation in egg rejection behavior between various host populations? How distinct and host-specialized are Cuckoo gentes? These questions are discussed in relation to existing knowledge and future perspectives.展开更多
基金Wildlife Conservation and Management of National Forestry Bureau of China
文摘The vegetation and soil are mutual environmental factors, soil characteristics, such as chemical properties and microorganism that affect the vegetation occurrence, development and succession speed. In this study, we evaluated the structure of microbial communities of rhizosphere of Cowskin Azalea(Rhododendron aureum Georgi) populations and compared with non-rhizosphere soils at four sample sites of the Changbai Mountains, China, and analyzed the correlation between chemical properties of soil and microbial communities. The results showed that microbial structure and soil chemical properties are significant superior to non-rhizosphere at all four sample sites. The rhizosphere microorganisms are mainly composed of bacteria, actinomycetes, followed by fungi least. The principal component analysis(PCA) biplot displayed that there are differences between rhizosphere and non-rhizosphere soils for microflora; Through correlation analysis, we found that the bacteria is clearly influenced by p H on the Changbai Mountains, besides p H, other soil features such as NO3–-N. These data highlight that R. aureum as the dominant vegetation living in the alpine tundra is a key factor in the formation of soil microorganism and improving soil fertility, and is of great significance for the maintenance of alpine tundra ecosystem.
文摘In Europe, eggs of the Common Cuckoo (Cuculus canorus) have been found in more than 125 different host species. However, very few species are frequently parasitized. The Cuckoo is divided into several distinct races termed gentes. Females of each gens specialize in parasitizing a particular host species. More than 20 such gentes are recognized in Europe. Each female Cuckoo lays eggs of constant appearance. Most gentes can be separated based on their distinct egg types, which in many cases mimic those of their hosts. Different gentes may occur in sympatry or may be separated geographically. Some gentes may occur in restricted parts of the host’s distribution area. These patterns raise some fundamental questions like: Why are some passerine species preferred as hosts while others are not? Why does a host population consist of individuals either accepting or rejecting Cuckoo eggs? Why is there marked variation in egg rejection behavior between various host populations? How distinct and host-specialized are Cuckoo gentes? These questions are discussed in relation to existing knowledge and future perspectives.
