Erland Susanne, Finlay Roger, Söderström Bengt
Department of Microbial Ecology, University of Lund, Ecology Building, Helgonavägen 5, S-223 62 Lund, Sweden.
New Phytol. 1991 Oct;119(2):235-242. doi: 10.1111/j.1469-8137.1991.tb01026.x.
The effects of changed substrate pH on translocation and partitioning of C-labeled plant assimilates were examined in laboratory microcosms containing mycorrhizal (unidentified fungal isolate 'Pink FMT 87:2') and non-mycorrhizal seedlings of Pinus sylvestris L. and Pinus contorta Dougl. ex Loud. The mycorrhizal plants had intact mycelial systems at different developmental stages, and microcosms contained non-sterile peat (pH 3.8) or peat adjusted to different pH values with CaO. In systems with mycorrhizal mycelium which had just started to colonize the peat no significant differences in C assimilation were found, either with respect to substrate pH or mycorrhizal status of the plant. Loss of activity from the mycorrhizal plants was more rapid, however, probably mainly as a result of increased respiration from the infected root systems. After 8 wk growth in peat at pH 3.8 and 5.2 shoot weights of all seedlings were the same, whereas non-mycorrhizal plants had root systems twice the size of the mycorrhizal ones. In plants with well developed extramatrical mycelia translocation of labeled carbon to the mycelium growing at pH 3.8 was faster than that to mycelium growing at pH 5.2. After 4 d incubation, however, the percentage of the originally supplied carbon present in the mycelium was 5% regardless of substrate pH. Activity found in the peat surrounding non-mycorrhizal plants rarely exceeded 0.3%.
在含有菌根（未鉴定的真菌分离株“粉红FMT 87:2”）以及欧洲赤松和扭叶松非菌根幼苗的实验室微观系统中，研究了底物pH值变化对碳标记植物同化物转运和分配的影响。菌根植物在不同发育阶段具有完整的菌丝系统，微观系统包含非无菌泥炭（pH 3.8）或用CaO调节至不同pH值的泥炭。在菌根菌丝刚开始在泥炭中定殖的系统中，无论底物pH值或植物的菌根状态如何，碳同化均未发现显著差异。然而，菌根植物活性的丧失更快，这可能主要是由于受感染根系呼吸作用增强所致。在pH 3.8和5.2的泥炭中生长8周后，所有幼苗的地上部分重量相同，而非菌根植物的根系大小是菌根植物的两倍。在具有发达的根外菌丝的植物中，标记碳向生长在pH 3.8的菌丝的转运速度比向生长在pH 5.2的菌丝的转运速度快。然而，培养4天后，无论底物pH值如何，菌丝中最初供应的碳的百分比均为5%。在非菌根植物周围的泥炭中发现的活性很少超过0.3%。
