Research Center of Forest Ecology, Forestry College, Guizhou University, Guiyang, 550025, China.
State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China.
BMC Plant Biol. 2024 Nov 19;24(1):1093. doi: 10.1186/s12870-024-05794-y.
Plant nutrient resorption is crucial for the efficient conservation of nutrients. However, the mechanisms through which abiotic and biotic factors control nutrient resorption remain controversial. We investigated leaf nitrogen (N) and phosphorus (P) resorption efficiency (NRE and PRE) and resorption proficiency, as well as the underlying mechanisms for each plant functional type (PFT: non-legume herbs, non-legume shrubs, and legumes) by collecting green and senescent leaves of 59 species covering 106 sites from arid and semiarid regions of northwest China.
Legumes had much lower leaf NRE and much higher senesced leaf N than the other two PFTs; they had similar leaf PRE to non-legume shrubs. Non-legume herbs exhibited the highest leaf P resorption. Climate, particularly temperature, increased leaf N resorption in non-legume herbs; however, climate, particularly decreasing precipitation, decreased leaf P resorption in legumes. Leaf nutrient resorption in non-legume shrubs decreased with increasing soil fertility, but leaf NRE in legumes increased. Leaf traits contributed more to leaf N and P resorption than climate and soil. Senesced leaf N and P concentrations increased along the resource-conservative to resource-acquisitive strategy axis. There were strong negative relationships between leaf NRE and senesced leaf N concentration and between leaf PRE and senesced leaf P concentration, in which legumes had a lower slope than non-legumes.
These findings suggest that ecological strategies and N-fixing plant types modulate nutrient resorption. Plants with the resource-conservative strategy are highly proficient in nutrient resorption. We highlight the importance of leaf economics traits and spectrum in regulating leaf nutrient resorption in drylands in the context of global climate change, potentially modulating plant traits and community composition. The higher proficient and efficient N and P resorption of plant species suggests the crucial importance of nutrient resorption in the nutrient cycling of harsh drylands.
植物养分再吸收对于养分的有效保存至关重要。然而，控制养分再吸收的非生物和生物因素的机制仍存在争议。我们通过收集来自中国西北干旱和半干旱地区 106 个地点的 59 个物种的绿色和衰老叶片，研究了每个植物功能型（PFT：非豆科草本植物、非豆科灌木和豆科植物）的叶片氮（N）和磷（P）再吸收效率（NRE 和 PRE）和再吸收效率，以及潜在的机制。
豆科植物的叶片 NRE 明显较低，衰老叶片 N 明显较高；它们的叶片 PRE 与非豆科灌木相似。非豆科草本植物的叶片 P 再吸收最高。气候，特别是温度，增加了非豆科草本植物的叶片 N 再吸收；然而，气候，特别是降水减少，降低了豆科植物的叶片 P 再吸收。非豆科灌木的叶片养分再吸收随着土壤肥力的增加而减少，但豆科植物的叶片 NRE 增加。叶片性状对叶片 N 和 P 再吸收的贡献大于气候和土壤。衰老叶片 N 和 P 浓度沿着资源保守到资源获取策略轴增加。叶片 NRE 与衰老叶片 N 浓度之间以及叶片 PRE 与衰老叶片 P 浓度之间存在强烈的负相关关系，其中豆科植物的斜率低于非豆科植物。
这些发现表明，生态策略和固氮植物类型调节养分再吸收。具有资源保守策略的植物在养分再吸收方面非常高效。我们强调了叶片经济性状和光谱在调节干旱地区叶片养分再吸收方面的重要性，这可能调节植物性状和群落组成。植物物种更高的高效和有效的 N 和 P 再吸收表明养分再吸收在恶劣干旱地区养分循环中的至关重要性。
