CAS Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, Yunnan 666303, China.
T-STAR Core Team, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, Yunnan 666303, China.
Tree Physiol. 2024 Feb 6;44(1). doi: 10.1093/treephys/tpad149.
Leaf nutrient resorption and drought resistance are crucial for the growth and survival of plants. However, our understanding of the relationships between leaf nutrient resorption and plant drought resistance is still limited. In this study, we investigated the nitrogen and phosphorus resorption efficiencies (NRE and PRE), leaf structural traits, leaf osmotic potential at full hydration (Ψosm), xylem water potential at 50% loss of xylem-specific hydraulic conductivity (P50) and seasonal minimum water potential (Ψmin) for 18 shrub and tree species in a semiarid savanna ecosystem, in Southwest China. Our results showed that NRE and PRE exhibited trade-off against drought resistance traits (Ψosm and P50) across woody species. Moreover, this relationship was modulated by leaf structural investment. Species with low structural investment (e.g., leaf mass per area, leaf dry mass content and leaf construction cost [LCC]) tend to have high NRE and PRE, while those with high LCCs show high drought resistance, showing more negative Ψosm and P50.These results indicate that species with a lower leaf structural investment may have a greater need to recycle their nutrients, thus exhibiting higher nutrient resorption efficiencies, and vice versa. In conclusion, nutrient resorption efficiency may be a crucial adaptation strategy for coexisting plants in semiarid ecosystems, highlighting the importance of understanding the complex relationships between nutrient cycling and plant survival strategies.
叶片养分回收和抗旱性对植物的生长和存活至关重要。然而，我们对叶片养分回收与植物抗旱性之间关系的理解仍然有限。在这项研究中，我们调查了半干旱草原生态系统中 18 种灌木和乔木物种的氮磷养分回收效率（NRE 和 PRE）、叶片结构特征、叶片充分水合时的渗透势（Ψosm）、木质部特定水力传导率损失 50%时的木质部水势（P50）和季节性最小水势（Ψmin）。我们的结果表明，NRE 和 PRE 与抗旱性特征（Ψosm 和 P50）在木本物种之间存在权衡关系。此外，这种关系受到叶片结构投资的调节。叶片结构投资低的物种（例如，叶面积质量比、叶干质量含量和叶构建成本[LCC]）往往具有较高的 NRE 和 PRE，而 LCC 较高的物种则表现出较高的抗旱性，表现出更负的 Ψosm 和 P50。这些结果表明，叶片结构投资较低的物种可能更需要回收养分，因此表现出更高的养分回收效率，反之亦然。总之，养分回收效率可能是半干旱生态系统中共存植物的关键适应策略，突出了理解养分循环与植物生存策略之间复杂关系的重要性。
