Heinemeyer A, Fitter A H
Department of Biology, University of York, PO Box 373, York YO10 5YW, UK.
J Exp Bot. 2004 Feb;55(396):525-34. doi: 10.1093/jxb/erh049.
The growth response of the hyphae of mycorrhizal fungi has been determined, both when plant and fungus together and when only the fungus was exposed to a temperature change. Two host plant species, Plantago lanceolata and Holcus lanatus, were grown separately in pots inoculated with the mycorrhizal fungus Glomus mosseae at 20/18 degrees C (day/night); half of the pots were then transferred to 12/10 degrees C. Plant and fungal growth were determined at six sequential destructive harvests. A second experiment investigated the direct effect of temperature on the length of the extra-radical mycelium (ERM) of three mycorrhizal fungal species. Growth boxes were divided in two equal compartments by a 20 micro m mesh, allowing only the ERM and not roots to grow into a fungal compartment, which was either heated (+8 degrees C) or kept at ambient temperature. ERM length (LERM) was determined on five sampling dates. Growth of H. lanatus was little affected by temperature, whereas growth of P. lanceolata increased with temperature, and both specific leaf area (SLA) and specific root length (SRL) increased independently of plant size. Percentage of colonized root (LRC) and LERM were positively correlated with temperature when in symbiosis with P. lanceolata, but differences in LRC were a function of plant biomass. Colonization was very low in H. lanatus roots and there was no significant temperature effect. In the fungal compartment LERM increased over time and was greatest for Glomus mosseae. Heating the fungal compartment significantly increased LERM in two of the three species but did not affect LRC. However, it significantly increased SRL of roots in the plant compartment, suggesting that the fungus plays a regulatory role in the growth dynamics of the symbiosis. These temperature responses have implications for modelling carbon dynamics under global climate change.
已确定了菌根真菌菌丝在植物和真菌共同作用时以及仅真菌暴露于温度变化时的生长反应。两种寄主植物物种，即披针叶车前和绒毛草，在接种了摩西球囊霉菌根真菌的花盆中于20/18摄氏度（白天/夜晚）分别培养；然后将一半的花盆转移到12/10摄氏度。在连续六次破坏性收获时测定植物和真菌的生长情况。第二个实验研究了温度对三种菌根真菌物种根外菌丝（ERM）长度的直接影响。生长箱通过一个20微米的网被分成两个相等的隔室，只允许ERM而不是根生长到一个真菌隔室中，该真菌隔室要么加热（升高8摄氏度）要么保持在环境温度。在五个采样日期测定ERM长度（LERM）。绒毛草的生长受温度影响很小，而披针叶车前的生长随温度增加，并且比叶面积（SLA）和比根长（SRL）均独立于植物大小而增加。与披针叶车前共生时，定殖根百分比（LRC）和LERM与温度呈正相关，但LRC的差异是植物生物量的函数。绒毛草根系中的定殖率非常低，且没有显著的温度效应。在真菌隔室中，ERM随时间增加，并且对摩西球囊霉来说是最大的。加热真菌隔室在三种物种中的两种中显著增加了ERM，但不影响LRC。然而，它显著增加了植物隔室中根的SRL，表明真菌在共生体的生长动态中起调节作用。这些温度反应对全球气候变化下的碳动态建模具有重要意义。
