4种外生菌根真菌对氮源的响应研究

Responses on four ectomycorrhizal fungi under nitrogen sources treatment

采用平板培养法对4种外生菌根真菌(ectomycorrhizal fungi,ECMF)最适氮源类型以及耐氮浓度开展了研究,旨在探讨氮沉降背景下ECMF对环境的适应性及其在自然生境中的多样性变化趋势。结果表明:4种ECMF仅彩色豆马勃(Pisolithus tinctorius,Pt)偏好NO3^-,其它菌根真菌均偏好NH4^+。在氮源类型筛选中,与CK处理相比,NO3-对浅黄根须腹菌(Rhizopogon luteolus,Rl)和粘盖牛肝菌(Sulillus bovinus,Sb)的菌丝生长无影响,对浅灰小牛肝菌(Boletinus grisellus,Bg)的菌丝生长的影响表现为抑制作用。在混合氮源中,Pt菌丝生长偏好低氮环境,其最适氮浓度阈值区在0.212~0.318 g·L^-1。在NH4+环境中,Rl菌丝生长偏好低氮环境,且随着氮浓度的升高菌丝生长受到抑制,菌丝生长最适氮浓度为0.027~0.080 g·L^-1;Sb菌丝生长最适氮浓度为0.106~0.318 g·L^-1;Bg菌丝生长偏好高氮环境,其最适氮源浓度在0.212~0.424 g·L^-1。

In order to analyze the adaptability of ectomycorrhizal fungi(ECMF)and the trend of the its variation diversity in natural habitats under nitrogen deposition,the optimum nitrogen source types and nitrogen tolerance concentration of four ECMF,including Pisolithus tinctorius(Pt),Rhizopogon luteolus(Rl),Sulillus bovinus(Sb)and Boletus grisellus(Bg),were studied by plate culture method.The NO3^--N was preferred by Pt,but NH4^+-N were selected by the other three ECMF.Compared with CK treatment,NO3^--N had no effect on the mycelium growth of Rl and Sb in the screening of nitrogen source,but which inhibited the mycelium growth of Bg.Low nitrogen environment was preferred for the mycelium growth of Pt in the mixed nitrogen sources,and the threshold of nitrogen tolerance was 0.212~0.318 g·L^-1.Low nitrogen environment was preferred for the mycelium growth of Rl in the NH4^+-N environment,and the optimum nitrogen concentration was 0.0265~0.0795 g·L^-1.The mycelium growth of Rl was inhibited with the increase of nitrogen concentration.The optimum nitrogen concentration was 0.106~0.318 g·L^-1 for Sb mycelium growth.However,the high nitrogen environment was selected for Bg mycelium growth,and the optimum nitrogen source concentration was 0.212~0.424 g·L^-1.