Wang Minggang, Wang Zhongbin, Guo Mingjie, Qu Laiye, Biere Arjen
Ministry of Education Key Laboratory of Silviculture and Conservation, Beijing Forestry University, Beijing, China.
Ecological Observation and Research Station of Heilongjiang Sanjiang Plain Wetlands, National Forestry and Grassland Administration, Beijing Forestry University, Beijing, China.
Front Plant Sci. 2023 Jan 26;14:1101932. doi: 10.3389/fpls.2023.1101932. eCollection 2023.
Fitness of plants is affected by their symbiotic interactions with arbuscular mycorrhizal fungi (AMF), and such effects are highly dependent on the environmental context.
In the current study, we inoculated the nursery shrub species with AMF species under contrasting levels of soil water and nutrients (diammonium phosphate fertilization), to assess their effects on plant growth, physiology and natural infestation by herbivores.
Overall, plant biomass was synergistically enhanced by increasing soil water and soil nutrient levels. However, plant height was surprisingly repressed by AMF inoculation, but only under low water conditions. Similarly, plant biomass was also reduced by AMF but only under low water and nutrient conditions. Furthermore, AMF significantly reduced leaf phosphorus levels, that were strongly enhanced under high nutrient conditions, but had only minor effects on leaf chlorophyll and proline levels. Under low water and nutrient conditions, specific root length was enhanced, but average root diameter was decreased by AMF inoculation. The negative effects of AMF on plant growth at low water and nutrient levels may indicate that under these conditions AMF inoculation does not strongly contribute to nutrient and water acquisition. On the contrary, the AMF might have suppressed the direct pathway of water and nutrient absorption by the plant roots themselves despite low levels of mycorrhizal colonization. AMF inoculation reduced the abundance of the foliar herbivore on plants that had been grown on the low nutrient soil, but not on high nutrient soil. Fertilization enhanced the abundance of this herbivore but only in plants that had received the high water treatment. The lower abundance of the herbivore on AMF plants could be related to their decreased leaf P content. In conclusion, our results indicate that AMF negatively affect the growth of but makes them less attractive to a dominant herbivore.
Our study highlights that plant responses to AMF depend not only on the environmental context, but that the direction of the responses can differ for different components of plant performance (growth vs. defense).
植物的适应性受到其与丛枝菌根真菌（AMF）共生相互作用的影响，且这种影响高度依赖于环境背景。
在本研究中，我们在土壤水分和养分（磷酸二铵施肥）水平不同的情况下，用AMF物种接种苗圃灌木物种，以评估其对植物生长、生理以及食草动物自然侵染的影响。
总体而言，土壤水分和土壤养分水平的增加协同提高了植物生物量。然而，AMF接种出人意料地抑制了株高，但仅在低水分条件下如此。同样，AMF也降低了植物生物量，但仅在低水分和低养分条件下。此外，AMF显著降低了叶片磷含量，在高养分条件下叶片磷含量大幅增加，但对叶片叶绿素和脯氨酸水平影响较小。在低水分和低养分条件下，AMF接种增加了比根长，但降低了平均根直径。AMF在低水分和低养分水平下对植物生长的负面影响可能表明，在这些条件下，AMF接种对养分和水分获取的贡献不大。相反，尽管菌根定殖水平较低，但AMF可能抑制了植物根系自身吸收水分和养分的直接途径。AMF接种降低了在低养分土壤上生长的植物上叶面食草动物的数量，但在高养分土壤上生长的植物上则没有。施肥增加了这种食草动物的数量，但仅在接受高水分处理的植物中如此。AMF植物上食草动物数量较少可能与其叶片磷含量降低有关。总之，我们的结果表明，AMF对[研究植物名称]的生长有负面影响，但使其对优势食草动物的吸引力降低。
我们的研究强调，植物对AMF的反应不仅取决于环境背景，而且反应方向可能因植物性能的不同组成部分（生长与防御）而异。
