Su Lei, Liu Mengzhou, You Chengming, Guo Qun, Hu Zhongmin, Yang Zhongling, Li Guoyong
International Joint Research Laboratory for Global Change Ecology School of Life Sciences Henan University Kaifeng China.
College of Geography and Environmental Science Henan University Kaifeng China.
Ecol Evol. 2021 Oct 11;11(21):15020-15029. doi: 10.1002/ece3.8185. eCollection 2021 Nov.
Previous studies have demonstrated changes in plant growth and reproduction in response to nutrient availability, but responses of plant growth and reproduction to multiple levels of nutrient enrichment remain unclear. In this study, a factorial field experiment was performed with manipulation of nitrogen (N) and phosphorus (P) availability to examine seed production of the dominant species, , in response to N and P addition in a temperate steppe. There were three levels of N and P addition in this experiment, including no N addition (0 g N m year), low N addition (10 g N m year), and high N addition (40 g N m year) for N addition treatment, and no P addition (0 g P m year), low P addition (5 g P m year), and high P addition (10 g P m year) for P addition treatment. Low N addition enhanced seed production by 814%, 1371%, and 1321% under ambient, low, and high P addition levels, respectively. High N addition increased seed production by 2136%, 3560%, and 3550% under ambient, low, and high P addition levels, respectively. However, P addition did not affect seed production in the absence of N addition, but enhanced it under N addition. N addition enhanced seed production mainly by increasing the tiller number and inflorescence abundance per plant, whereas P addition stimulated it by decreasing the plant density yet stimulating height of plants and their seed number per inflorescence. Our results indicate seed production is not limited by P availability but rather by N availability in the temperate steppe, whereas seed production will be increased by P addition when N availability is improved. These findings enable a better understanding of plant reproduction dynamics in the temperate steppe under intensified nutrient enrichment and can inform their improved management in the future.
以往的研究已经证明，植物的生长和繁殖会因养分有效性而发生变化，但植物生长和繁殖对多个养分富集水平的响应仍不明确。在本研究中，进行了一项析因田间试验，通过控制氮（N）和磷（P）的有效性，来研究温带草原优势物种的种子产量对添加N和P的响应。本试验设置了三个N和P添加水平，N添加处理包括不添加N（0 g N m² 年）、低N添加（10 g N m² 年）和高N添加（40 g N m² 年），P添加处理包括不添加P（0 g P m² 年）、低P添加（5 g P m² 年）和高P添加（10 g P m² 年）。低N添加分别使环境、低和高P添加水平下的种子产量提高了814%、1371%和1321%。高N添加分别使环境、低和高P添加水平下的种子产量提高了2136%、3560%和3550%。然而，在不添加N的情况下，添加P不影响种子产量，但在添加N的情况下会提高种子产量。添加N主要通过增加单株分蘖数和花序丰度来提高种子产量，而添加P则通过降低植株密度、促进植株高度及其每花序种子数来刺激种子产量。我们的结果表明，温带草原的种子产量不受P有效性的限制，而是受N有效性的限制，而当N有效性提高时，添加P会增加种子产量。这些发现有助于更好地理解温带草原在强化养分富集下的植物繁殖动态，并可为未来其更好的管理提供参考。
