Carbon transfer between plants and its control in networks of arbuscular mycorrhizas
Carbon transfer between plants and its control in networks of arbuscular mycorrhizas
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DOI：
10.1046/j.1365-2435.1998.00206.x
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发表时间：
1998-06-01
影响因子：
5.2
通讯作者：
Scrimgeour, C
中科院分区：
文献类型：
--
作者：
Fitter, AH;Graves, JD;Scrimgeour, C
两项使用稳定同位素C-13的研究表明，大量的碳可以在由丛枝菌根真菌连接的植物之间移动。2、测定了狗牙根（Cynodon dactylon）（C-4，δ（13）C约为-14ppm）和长叶车前（Plantago lanceolata）（C-3，δ（13）C约为-28ppm）两种植物之间的碳转移。为了检验植物之间转移的碳一直保持在真菌结构中的假设，植物生长两次收获;在第一次收获时，它们被修剪到地面水平，以便芽的再生长需要从根部运输碳。我们还测试了真菌的生长方向的影响，以确定C是否被运输出或进入一个新的殖民地的根，以及在CO2浓度升高的植物，以增加碳化合物在根中的可用性。无论根系是否被20 μ m的网（排除根而不是菌丝）或0.45 μ m的网（也用作菌丝的屏障）隔开，都会发生转移。我们相信，实验中获得的高根密度允许菌丝穿过两个密集根火星之间的更细的网格。修剪植物没有导致C从根到枝的任何移动，因此限制了所有转移的C保留在真菌结构中的预测。5，真菌的生长方向不影响转移的方向，植物生长的CO2浓度也不影响转移的方向。转移的C量与根中囊泡的频率呈正相关，但与菌丝的频率呈负相关，如果C移动到发育中的定殖单位，从而有效地给予植物一种“自由”共生，与内部菌丝的相关性应该是正的。与囊泡的正相关表明C正在进入真菌的储存结构。我们提出了一个mycorcentric视图的现象，植物间的C转移，在根内的真菌菌落被视为一个扩展的菌丝体之间的真菌移动资源取决于其自身的增长动态的一部分。我们不认为这种转移对植物碳预算或适合度有影响，但它可能是理解真菌碳预算的一个主要因素。
1, Two studies using the stable-isotope C-13 have shown that large amounts of carbon can move between plants linked by arbuscular mycorrhizal fungi. Quantities comparable to the carbon cost of the symbiosis for an individual plant may be transferred.2, We measured C transfer between linked plants of the grass Cynodon dactylon (C-4, delta(13)C approximate to - 14 parts per thousand) and the herb Plantago lanceolata (C-3, delta(13)C similar to - 28 parts per thousand). To test the hypothesis that the carbon transferred between plants remained in fungal structures at all times, plants were grown for two harvests; at the first harvest they were clipped to ground level, so that shoot re-growth required the transport of carbon from the roots. We also tested the influence of the direction of growth of the fungus, to determine whether C was transported out of or into a newly colonized root, and of growing plants in elevated CO2, to increase the availability of carbon compounds in the roots.3, Large amounts of C were transferred between linked plants, more so into Plantago than into Cynodon roots. Transfer occurred whether root systems were separated by a 20 mu m mesh, that excluded roots but not hyphae, or a 0.45 mu m mesh, intended to act as a barrier to hyphae as well. We believe that the high root densities achieved in the experiment allowed hyphae to cross the finer mesh between the two dense root mars.4. Clipping the plants did not result in any movement of C from roots to shoots, thus confining the prediction that all C transferred remains in fungal structures.5, The direction of growth of the fungus did not affect the direction of transfer, nor did the CO2 concentration in which the plants were grown.6, The amount of C transferred was a positive correlate of the frequency of vesicles in the roots but a negative correlate of the frequency of hyphae, if C were moving into developing colonization Units, thus effectively giving the plant a 'free' symbiosis, the correlation with internal hyphae should be positive. The positive correlation with vesicles suggests that C is moving into fungal storage structures.7. We propose a mycocentric view of the phenomenon of interplant C transfer, in which the fungal colonies within roots are seen as parts of an extended mycelium between which the fungus moves resources depending on the dynamics of its own growth. We do not believe that the transfer has an impact on plant C budgets or fitness, but that it may be a major element in the understanding of fungal C budgets.