Aims

Plants with a history of overgrazing show trait-mediated legacy effects. These legacy effects strongly influence the growth dynamics and stress tolerance of plants, thus affecting ecosystem functioning. Long-term overgrazing has dramatic effects on plant growth and carbon assimilation via asexual propagation. However, the link between nitrogen (N) absorbability and assimilation with grazing-induced plant legacy effects remains largely unknown.

Methods

We investigated the strength of legacy effects induced by long-term overgrazing on N uptake and metabolism in the clonal plant Leymus chinensis, and its associated changes at the physiological and molecular levels. These tests were conducted in both field and greenhouse experiments.

Results

The clonal offspring of overgrazed L. chinensis were significantly smaller than the control offspring, with lower individual N uptake and utilisation efficiency, indicating that the N dynamics were affected by plant legacy effects. The response ratios of root length and biomass to N patches in the clonal offspring of overgrazed L. chinensis were significantly higher than those of the control, indicating that root nutrient foraging plasticity increased in response to grazing-induced N heterogeneity. Moreover, the observed plant legacy effects decreased N acquirement but significantly increased N assimilation by increasing N resorption efficiency, with biotic stress memory activated at the enzymatic and transcriptional levels.

Conclusions

We propose that multigenerational exposure of perennial plants to herbivore foraging can produce a legacy effect on N uptake, which offers insights into the potential resilience of grasslands to overgrazing.

中文翻译：

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历史放牧增强了羊草克隆后代的根觅食可塑性而不是氮吸收能力

宗旨

具有过度放牧历史的植物表现出性状介导的遗产效应。这些遗留效应强烈影响植物的生长动态和胁迫耐受性，从而影响生态系统功能。长期过度放牧通过无性繁殖对植物生长和碳同化产生显着影响。然而，氮 (N) 吸收能力和同化与放牧引起的植物遗产效应之间的联系在很大程度上仍然未知。

方法

我们研究了长期过度放牧对克隆植物羊草N 吸收和代谢的影响强度，及其在生理和分子水平上的相关变化。这些测试在田间和温室实验中进行。

结果

过度放牧的中华白菜的克隆后代显着小于对照后代，个体对氮的吸收和利用效率较低，表明氮动态受植物遗产效应的影响。根长和生物质的反应比率，以N个贴片在过度放牧的克隆后代羊草均较控制的显著更高，这表明根养分觅食可塑性响应增加放牧诱导Ñ异质性。此外，观察到的植物遗留效应减少了 N 的获取，但通过提高 N 吸收效率显着增加了 N 同化，在酶促和转录水平激活了生物胁迫记忆。

结论

我们建议多年生植物多代暴露于食草动物觅食可以对 N 吸收产生遗留效应，这提供了对草原对过度放牧的潜在恢复力的见解。