Mikkelsen Bolette L, Rosendahl Søren, Jakobsen Iver
Biosystems Department, Risø National Laboratory for Sustainable Energy, Technical University of Denmark, P.O. Box 49, DK-4000 Roskilde, Denmark.
New Phytol. 2008;180(4):890-8. doi: 10.1111/j.1469-8137.2008.02623.x. Epub 2008 Sep 17.
Fusions between individual mycelia of arbuscular mycorrhizal (AM) fungi have been observed in two-dimensional systems but never in soil systems. Here, phosphorus ((32)P) labelling was used to demonstrate nutrient transfer between individual mycelia and to investigate the possible role of anastomosis. Trifolium subterraneum colonized by Glomus mosseae were grown in root-retaining mesh bags, which were placed 20 cm apart. The mycelium of one plant, the donor, had access to (32)P-labelled soil placed adjacent to the mesh bag. Transfer of (32)P from the donor mycelium to the receiver plant was measured at three harvests. In a second-harvest control treatment the receiver was colonized by Glomus caledonium in order to determine whether transfer occurred by other means than hyphal fusions. Significant amounts of P were transferred to the receiver plant at the last harvests when the two mycelia of G. mosseae overlapped. The transfer probably occurred via anastomoses between the mycelia as no transfer of (32)P was detected between the mycelia of different fungi at the second harvest. The indicated ability of AM fungal mycelia to anastomose in soil has implications for the formation of large plant-interlinking functional networks, long-distance nutrient transport and retention of nutrients in readily plant-available pools.
丛枝菌根（AM）真菌的单个菌丝体之间的融合在二维系统中已被观察到，但在土壤系统中从未被观察到。在此，利用磷（³²P）标记来证明单个菌丝体之间的养分转移，并研究吻合作用的可能作用。用摩西球囊霉定殖的 subterraneum 三叶草种植在保留根系的网袋中，网袋相距20厘米放置。其中一株植物（供体）的菌丝体可以接触到放置在网袋旁边的³²P标记土壤。在三次收获时测量了³²P从供体菌丝体向受体植物的转移。在第二次收获的对照处理中，受体由喀里多尼亚球囊霉定殖，以确定转移是否通过菌丝融合以外的其他方式发生。当摩西球囊霉的两个菌丝体重叠时，在最后一次收获时有大量的磷转移到了受体植物中。由于在第二次收获时未检测到不同真菌的菌丝体之间有³²P转移，所以这种转移可能是通过菌丝体之间的吻合发生的。AM真菌菌丝体在土壤中吻合的能力表明，这对形成大型的植物相互连接的功能网络、长距离养分运输以及养分在易于植物利用的库中的保留具有重要意义。
