Nitrogen addition and warming modulate the pathogen impact on plant biomass by shifting intraspecific functional traits and reducing species richness
Nitrogen addition and warming modulate the pathogen impact on plant biomass by shifting intraspecific functional traits and reducing species richness
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DOI：
10.1111/1365-2745.14043
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发表时间：
2022-11
影响因子：
5.5
通讯作者：
Xuebin Yan;Mayank Kohli;Yue Wen;Xiaoyi Wang;Yuan-Chen Zhang;Fei Yang;Xianhui Zhou;G. Du;
中科院分区：
文献类型：
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作者：
Xuebin Yan;Mayank Kohli;Yue Wen;Xiaoyi Wang;Yuan-Chen Zhang;Fei Yang;Xianhui Zhou;G. Du;
叶面真菌病原体可显著减少植物生物量。这种影响可以通过环境条件，如土壤氮的有效性和空气温度来调节。持续的全球变化正在改变这些变量，从而与病原体相互作用，影响植物生物量，但它们之间的相互作用的实验测试是稀缺的。我们在西藏高寒草甸进行了为期4年的田间试验，以研究氮添加，变暖和叶面病原体（通过杀菌剂应用）对植物生物量的交互作用。我们还测量了植物功能性状，物种丰富度和丰度，以测试这些相互作用的可能机制。结果表明，叶面真菌病原菌降低了植物群落生物量，从而削弱了氮对群落生物量的正效应。从机制上讲，氮的添加使植物群落向快速生长性状转变;这主要是由于种内性状值的变化，包括比叶面积和高度的增加。这些性状变化导致病原体对植物生物量的抑制更大，可能是因为与植物生长和防御资源分配相关的权衡。此外，物种丰富度的减少放大了病原体的影响下，氮添加由于增加的密度和易感性的最优势的物种（即嵩草capillifolia）。此外，变暖与病原体和氮添加没有相互作用来影响植物群落生物量，但它们的三向相互作用改变了K.毛叶。具体而言，变暖增强了氮添加对钾生物量的积极影响。在杀菌剂、低侵染区，毛叶藓的氮素效应减弱，而在未杀菌剂、高侵染区，毛叶藓的氮素效应减弱。合成.我们的研究结果表明，病原体如何与氮的添加和变暖的影响生物量的优势物种和整个植物群落。我们的研究强调了在评估生态系统对多个全球变化因素的响应时考虑叶面真菌病原体的重要性。
Foliar fungal pathogens can substantially reduce plant biomass. This effect can be modulated by environment conditions, such as soil nitrogen availability and air temperature. The ongoing global changes are altering these variables and thus interact with pathogens to influence plant biomass, but experimental test of their interactions is scarce. We conducted a 4‐year field experiment in a Tibetan alpine meadow to examine the interactive effects of nitrogen addition, warming and foliar pathogens (via fungicide application) on plant biomass. We also measured plant functional traits, species richness and abundance to test the possible mechanisms underlying these interactions. Our results showed that foliar fungal pathogens reduced plant community biomass under nitrogen addition, which in turn weakened the positive nitrogen effect on community biomass. Mechanistically, nitrogen addition shifted the plant communities towards fast‐growing traits; this happened predominantly because of changes in within‐species trait values, including an increase in specific leaf area and height. These trait changes resulted in greater suppression of plant biomass by pathogens, likely because of the trade‐offs associated with the allocation of resources to plant growth and defense. Moreover, the reduction in species richness amplified the pathogen effect under nitrogen addition due to the increased density and susceptibility of the most dominant species (i.e. Kobresia capillifolia). Furthermore, warming did not interact with pathogens and nitrogen addition to influence plant community biomass, but their three‐way interaction modified the biomass of K. capillifolia. Specifically, warming enhanced the positive effect of nitrogen addition on the biomass of K. capillifolia in the fungicide, low infection plots, while it weakened the nitrogen effect in the no fungicide, high infection plots. Synthesis. Our results demonstrate how pathogens interact with nitrogen addition and warming to influence the biomass of dominant species and the whole plant community. Our study highlights the importance of considering foliar fungal pathogens when assessing ecosystem responses to multiple global change factors.