ABSTRACT

Mycorrhizal fungi symbiotically associate with 80% of land plants, extend extraradical hyphae in the soil, and promote phosphorus (P) uptake in host plants. It is necessary to utilize the function of mycorrhizal symbiosis to cope with future depletion of P resources. Elucidation of the mycorrhizal colonization mechanism for utilizing mycorrhizal fungi, inoculation methods in agriculture and forestry, and new function of extraradical hyphae are described. Root exudates from P-deficient plants promoted extraradical hyphal growth and a hydrophobic fraction of the exudates promoted the formation of appressorium and subsequent colonization of the roots. Inoculation with a mycorrhizal fungus at the nursery stage reduced phosphate fertilizer application in Welsh onion cultivation and thus production cost. Inoculation with ectomycorrhizal and arbuscular mycorrhizal fungi increased the growth of tropical tree species under nursery and field conditions. Acid phosphatase was secreted from the extraradical hyphae of Rhizophagus clarus and its activity was increased under low P conditions. We found that utilization of AM fungi is useful as a strategy for sustainable P resource use.

摘要

菌根真菌与 80% 的陆地植物共生，在土壤中延伸根外菌丝，并促进寄主植物对磷 (P) 的吸收。有必要利用菌根共生的功能来应对未来磷资源的枯竭。阐述了利用菌根真菌的菌根定植机制、农林接种方法以及外源菌丝的新功能。来自缺磷植物的根分泌物促进了根外菌丝的生长，并且分泌物的疏水部分促进了附着胞的形成和随后的根定殖。在苗圃阶段接种菌根真菌降低了大葱栽培中的磷肥施用量，从而降低了生产成本。接种外生菌根和丛枝菌根真菌增加了热带树种在苗圃和田间条件下的生长。酸性磷酸酶由根外菌丝分泌Rhizophagus clarus及其活性在低磷条件下增加。我们发现利用 AM 真菌作为可持续磷资源利用的策略是有用的。