Purpose

Mowing may exert profound influences on nutrient acquisition strategies of herbaceous species due to the nutrient removal along with the mown plants. Nutrient uptake by roots and nutrient resorption from senescent leaves, are two main nutrient acquisition strategies of perennial herbaceous species. However, few studies have considered both nutrient acquisition strategies in exploring the effects of long-term mowing on the nutrient acquisition of perennial herbs.

Methods

We measured root traits of absorptive roots and leaf nitrogen resorption efficiency (NRE) of seven herbaceous species with different plant height on a long-term mowing experimental platform (2003-2020) in a temperate steppe.

Results

We found that root traits of tall and short species had little response to long-term mowing. While, mowing exerted opposite effects on leaf NRE of the two plant groups, i.e., mowing significantly decreased the NRE of tall species, but increased that of short species (except for Potentilla acaulis). Furthermore, root absorption capacity (indicated by root traits) was positively correlated with leaf NRE for tall species in control plots, but mowing eliminated this relationship. In contrast, for short species, root traits and leaf NRE had no correlation in control plots, while, mowing led to synergic relationship between root absorption capacity and leaf resorption rates.

Conclusions

Our results suggested that perennial herbs changed the relationships between alternative resource acquisition strategies in response to long-term mowing in temperate steppe. These findings provide new perspectives for understanding the adaptation of herbaceous species to mowing in the temperate steppe.

中文翻译：

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两种养分获取策略的响应：根性状和叶片养分吸收及其与温带草原长期割草的关系

目的

刈割可能会对草本植物的养分获取策略产生深远的影响，因为养分会随着修剪的植物一起被去除。根系对养分的吸收和衰老叶片的养分吸收是多年生草本植物的两种主要养分获取策略。然而，在探索长期割草对多年生草本植物养分获取的影响时，很少有研究考虑这两种养分获取策略。

方法

我们在温带草原的长期割草实验平台（2003-2020）上测量了七种不同株高草本植物的根系吸收性状和叶片氮吸收效率（NRE）。

结果

我们发现高矮种的根系特征对长期割草几乎没有反应。而割草对两组植物的叶片NRE产生相反的影响，即割草显着降低了高种植物的NRE，但增加了矮种植物的NRE（除了Potentilla acaulis）。此外，根吸收能力（由根性状表示）与对照地块中高种植物的叶片 NRE 呈正相关，但割草消除了这种关系。相比之下，对于矮种，根性状和叶片 NRE 在对照地块中没有相关性，而割草导致根吸收能力和叶片吸收率之间存在协同关系。

结论

我们的研究结果表明，多年生草本植物改变了替代资源获取策略之间的关系，以应对温带草原的长期割草。这些发现为了解草本植物对温带草原割草的适应提供了新的视角。