Chemical defense, mycorrhizal colonization and growth responses in Plantago lanceolata L.
Chemical defense, mycorrhizal colonization and growth responses in Plantago lanceolata L.
复制标题
DOI：
10.1007/s00442-009-1312-2
复制
发表时间：
2009-06-01
期刊：
影响因子：
2.7
通讯作者：
Klironomos, J. N.
中科院分区：
文献类型：
--
作者：
De Deyn, Gerlinde Barbra;Biere, A.;Klironomos, J. N.
化感物质保护植物免受草食动物和病原体的攻击地上和地下。这种植物防御是否通过减少植物互利共生体的利益而产生生态成本，在很大程度上是未知的。我们探讨了在长叶车前（Plantago lanceolata L.）中内在的植物化学防御和与丛枝菌根真菌（AMF）的地下互利共生之间的潜在权衡，使用来自选择环烯醚萜苷（IG）桃叶珊瑚苷和梓醇的低和高组成水平的品系的植物基因型。由于选择的基础上IG浓度在叶片中，我们首先研究IG浓度是否在根共变。根和叶IG浓度之间的基因型呈强正相关，表明叶和根防御的遗传相互依赖性。然后，我们发现根丛枝菌根定殖与根桃叶珊瑚甙浓度呈负相关。这种负相关性，观察到在植物生长与单一栽培的球囊霉intraradices和植物定植从整个领域的土壤接种。总体而言，AMF并没有影响植物的总生物量，初始的地上部生物量的增强被较低的根生物量和落叶后再生减少所抵消。虽然AMF对植物生物量的确切影响因基因型而异，但根中具有高IG水平和低AMF丛枝定殖的植物并不比具有低IG和高AMF丛枝定殖的植物产生更少的生物量。因此，虽然观察到高根化学防御和AMF丛枝定殖之间的明显权衡，这并没有负面影响植物对AMF的生长反应。有趣的是，AMF诱导了高根IG基因型杉木根桃叶珊瑚甙浓度的增加。我们的结论是，AMF不一定刺激植物生长，直接植物防御的次生代谢产物不一定减少潜在的好处AMF，AMF可以提高浓度的根化学防御，但这些反应是植物基因型依赖。
Allelochemicals defend plants against herbivore and pathogen attack aboveground and belowground. Whether such plant defenses incur ecological costs by reducing benefits from plant mutualistic symbionts is largely unknown. We explored a potential trade-off between inherent plant chemical defense and belowground mutualism with arbuscular mycorrhizal fungi (AMF) in Plantago lanceolata L., using plant genotypes from lines selected for low and high constitutive levels of the iridoid glycosides (IG) aucubin and catalpol. As selection was based on IG concentrations in leaves, we first examined whether IG concentrations covaried in roots. Root and leaf IG concentrations were strongly positively correlated among genotypes, indicating genetic interdependence of leaf and root defense. We then found that root AMF arbuscule colonization was negatively correlated with root aucubin concentration. This negative correlation was observed both in plants grown with monocultures of Glomus intraradices and in plants colonized from whole-field soil inoculum. Overall, AMF did not affect total biomass of plants; an enhancement of initial shoot biomass was offset by a lower root biomass and reduced regrowth after defoliation. Although the precise effects of AMF on plant biomass varied among genotypes, plants with high IG levels and low AMF arbuscule colonization in roots did not produce less biomass than plants with low IG and high AMF arbuscule colonization. Therefore, although an apparent trade-off was observed between high root chemical defense and AMF arbuscule colonization, this did not negatively affect the growth responses of the plants to AMF. Interestingly, AMF induced an increase in root aucubin concentration in the high root IG genotype of P. lanceolata. We conclude that AMF does not necessarily stimulate plant growth, that direct plant defense by secondary metabolites does not necessarily reduce potential benefits from AMF, and that AMF can enhance concentrations of root chemical defenses, but that these responses are plant genotype-dependent.