Pezzani Fabiana, Montaña Carlos, Guevara Roger
Departamento de Biología Evolutiva, Instituto de Ecología A. C, Km 2.5 Carretera Antigua a Coatepec Apartado Postal 63, Xalapa, Veracruz, México.
Mycorrhiza. 2006 Jun;16(4):285-295. doi: 10.1007/s00572-006-0044-y. Epub 2006 Apr 14.
The hypothesis that plant species are more responsive to mycorrhiza in late than in early successional stages was assessed in grasses from a successional process occurring in two-phase mosaics from the Mexican Chihuahuan Desert. We estimated the density of spores of arbuscular mycorrhizal (AM) fungi and the AM colonization of pioneer and late-successional grasses in the field. In growth chamber experiments, we tested the effect of the native AM fungal community on grasses growing in soils from different successional stages. Spore density was higher in late than in early successional stages. Late-successional species were more responsive to AM (positive AM responsiveness) whereas pioneer species were nondependent on mycorrhiza or if associated to AM fungi, the interaction showed a negative AM responsiveness for the seedling stage. Our findings showed that late successional species fitted the proposed models of mycorrhizal performance, but the two pioneer species differed in their AM condition and responsiveness. This further supports the idea that AM interactions are more complex along the successional processes than the predictions of the more widely cited hypotheses.
在墨西哥奇瓦瓦沙漠两阶段镶嵌体中发生的演替过程中的禾本科植物中，评估了植物物种在演替后期比早期对菌根更敏感的假设。我们在田间估计了丛枝菌根（AM）真菌的孢子密度以及先锋禾本科植物和演替后期禾本科植物的AM定殖情况。在生长室实验中，我们测试了本地AM真菌群落对生长在不同演替阶段土壤中的禾本科植物的影响。演替后期的孢子密度高于早期。演替后期的物种对AM更敏感（正AM响应），而先锋物种不依赖菌根，或者如果与AM真菌相关联，在幼苗期这种相互作用表现出负AM响应。我们的研究结果表明，演替后期的物种符合所提出的菌根性能模型，但两种先锋物种在其AM状况和响应方面存在差异。这进一步支持了这样一种观点，即沿着演替过程，AM相互作用比更广泛引用的假设的预测更为复杂。
