钾和磷有效性介导的热带森林生产力对季节性干旱的响应，这一成果由德国哥根廷大学Manu, Raphael小组经过不懈努力而取得。相关论文于2024年5月15日发表在《自然—地球科学》杂志上。
据介绍，热带森林的生产力受到养分限制，这可能影响其对季节性干旱的反应。然而，关于非洲热带森林营养限制的实验证据仍然很少。
研究小组在乌干达潮湿森林中进行了生态系统规模的全因子氮(N)-磷(P)-钾(K)添加试验，以研究养分控制对细凋落物产量和叶面化学的影响。8个因子处理在32个40×40m的地块中重复了4次。在为期3年的营养添加过程中，研究人员发现钾和磷对凋落叶产量的限制，显示出与生态系统对季节性干旱的响应有很强的联系。具体来说，在干旱季节，随着钾的添加，叶凋落物持续减少，而磷的添加只在第一年的长期干旱期间导致落叶量减少。施氮量对叶片凋落量影响不显著。
此外，钾的添加延迟了叶片凋落峰值的时间，强调了钾在水分胁迫条件下调节气孔孔径和信号传导的关键作用，并使得叶片寿命延长。叶面氮随氮、磷添加量的增加而增加，而钾是吸收最多的养分。研究结果强调，热带森林的生产力和恢复力，特别是在干旱条件下，可能取决于陆地钾和磷的有效性。
附：英文原文
Title: Response of tropical forest productivity to seasonal drought mediated by potassium and phosphorus availability
Author: Manu, Raphael, Iddris, Najeeb Al-Amin, Corre, Marife D., Aleeje, Alfred, Mwanjalolo, Majaliwa J. G., van Straaten, Oliver, Veldkamp, Edzo
Issue&Volume: 2024-05-15
Abstract: Tropical forest productivity is increasingly reported to be nutrient limited, which may affect its response to seasonal droughts. Yet experimental evidence on nutrient limitation from Afrotropical forests remains rare. We conducted an ecosystem-scale, full factorial nitrogen (N)–phosphorus (P)–potassium (K) addition experiment in a moist forest in Uganda to investigate nutrient controls on fine litter production and foliar chemistry. The eight factorial treatments were replicated four times in 32 plots of 40×40m each. During the three-year nutrient additions, we found K and P limitations on leaf litter production, exhibiting strong links to ecosystem responses to seasonal drought. Specifically, leaf litterfall consistently decreased in dry seasons with K additions, whereas P additions caused a reduction only during prolonged drought in the first year. Leaf litterfall was not significantly affected by N additions. Furthermore, K additions delayed the timing of leaf litterfall peak, underscoring the crucial role of K in regulating stomatal aperture and signalling during water-stress conditions and suggesting a prolonged leaf lifespan. Foliar N increased with N and P additions whereas K was the most resorbed nutrient. We conclude that the productivity and resilience of tropical forests, particularly under drier conditions, may depend on terrestrial K and P availability.
DOI: 10.1038/s41561-024-01448-8
Source: https://www.nature.com/articles/s41561-024-01448-8