Durall D M, Jones Melanie D, Tinker P B
Plant Mycorrhizal Unit, Natural Environment Research Council, Department of Plant Sciences, Parks Road, Oxford 0X1 3PF, UK.
Terrestrial and Freshwater Science Directorate, Natural Environment Research Council, Polaris House, North Star Avenue, Swindon SN2 1EU, UK.
New Phytol. 1994 Sep;128(1):109-114. doi: 10.1111/j.1469-8137.1994.tb03993.x.
The flow of carbon from plant to fungus in ectomycorrhizal associations has not been well quantified. The objective of this study was to use C to quantify the increase in fixed carbon translocated below ground in ectomycorrhizal relative to non-mycorrhizal willow (Salix viminalis L, Bowles hybrid). Rooted cuttings were inoculated with Thelephora terrestris (Ehrh). Fr. or left non-mycorrhizal. Non-mycorrhizal plants were grown at the same (4 mg kg bicarbonate-extractable P) (NM-P) or at a higher (21 mg kg ) soil P concentration (NM +P), one at which the non-mycorrhizal plants were similar in size to the mycorrhizal (M-P) plants. At 41, 51, 76 and 89 days after planting, the shoots were exposed to a pulse of CO . Plants were harvested after a 202 h chase period. The Cactivity was quantified in live fractions: shoot tissue, shoot respiration, 'root' tissue (= roots plus fungi), 'root' respiration (= CO released below ground) and soil. Of the total C detected in these five fractions, M-P plants allocated from 3.9% (harvest 1) to 11.5% (harvest 4) more to the below-ground fractions ('root' tissue, soil and 'root' respiration), than did the NM-P plants. Differences between NM+P and M-P plants were only half of those above (3.1 % and 4.4% at harvests 2 and 3, respectively, compared to 6.4 % and 7.4%, respectively for the difference between NM-P and M-P). Correction for differences in root/shoot ratio between M-P and NM-P plants eliminated the observed differences in carbon distribution only at the first three harvests. There was no evidence for increased 'root' respiration fates or rhizodeposition being responsible for the increased carbon diverted below ground by M-P plants.
在菌根共生关系中，碳从植物流向真菌的过程尚未得到很好的量化。本研究的目的是利用¹³C来量化相对于非菌根柳树（垂柳L，鲍尔斯杂交种），外生菌根中地下固定碳转运的增加量。将带根插条接种土生卧孔菌（Ehrh.）。Fr.或保持无菌根状态。非菌根植物在相同（4毫克/千克碳酸氢盐可提取磷）（NM-P）或更高（21毫克/千克）土壤磷浓度（NM +P）下生长，在该磷浓度下非菌根植物的大小与菌根（M-P）植物相似。种植后第41、51、76和89天，将地上部分暴露于¹³CO₂脉冲中。在202小时的追踪期后收获植物。在活体部分中对¹³C活性进行量化：地上组织、地上呼吸、“根”组织（=根加真菌）、“根”呼吸（=地下释放的CO₂）和土壤。在这五个部分中检测到的总¹³C中，M-P植物分配到地下部分（“根”组织、土壤和“根”呼吸）的比例比NM-P植物多3.9%（收获1）至11.5%（收获4）。NM+P和M-P植物之间的差异仅为上述差异的一半（收获2和3时分别为3.1%和4.4%，而NM-P和M-P之间的差异分别为6.4%和7.4%）。校正M-P和NM-P植物根/冠比的差异仅在前三次收获时消除了观察到的碳分布差异。没有证据表明“根”呼吸命运增加或根际沉积是M-P植物地下碳转移增加的原因。
