不同海拔花椒叶片-凋落物养分化学计量与重吸收的关系

Relationship between leaf-litter nutrient stoichiometry and resorption of Zanthoxylum planispinum var.din-tanensis at different altitudes

阐明贵州喀斯特高原峡谷区不同海拔顶坛花椒叶片和凋落物化学计量特征与养分重吸收率,有助于掌握养分保存与利用机制。选取531、640、780、871和1097 m共5个海拔的顶坛花椒为对象,采集叶片和凋落物数据,分析其养分含量、化学计量和养分重吸收率随海拔增加的分异规律,阐明叶片养分重吸收与化学计量之间的内在关联。结果表明:叶片和凋落物有机碳(OC)、全磷(TP)和全铁(TFe)均以海拔780 m为最高,叶片全锰(TMn)、全镁(TMg)和凋落物TMg含量表现出随海拔升高而增加的趋势,叶片和凋落物全氮(TN)、全钾(TK)、全钙(TCa)未随海拔发生显著分异。叶片和凋落物C∶P、Fe∶Mn、C∶Ca随海拔升高表现出先增加后降低的变化趋势,而叶片和凋落物Ca∶Mg则呈现随海拔升高而降低。叶片养分重吸收率随海拔的分异规律不完全一致,叶片P和K重吸收率以海拔780 m为最高,N、Fe和Mn重吸收率以海拔871 m为最高,海拔1097 m的Ca和Mg重吸收率显著高于其他海拔,而海拔1097 m的P、N和Fe重吸收率则均为负值。冗余分析结果表明,叶片养分重吸收率与化学计量之间具有很强的相关性。

Clarifying the stoichiometric characteristics of leaves and litters and nutrient resorption efficiency is helpful to understanding the mechanisms of nutrient conservation and utilization of Zanthoxylum planispinum var.dintanensis at different altitudes in the Guizhou karst plateau canyon area.Leaves and litters of Zanthoxylum planispinum var.dintanensis at different altitudes(531,640,780,871,and 1097 m)were collected.The differences of nutrient concentration,stoichiometry and nutrient resorption efficiency with increasing altitude were analyzed,and the relationship between nutrient resorption and stoichiometry was elucidated.The results showed that the concentrations of organic carbon(OC),total phosphorus(TP),and total iron(TFe)in leaves and litters were highest at the altitude of 780 m.The total manganese(TMn)and total magnesium(TMg)concentrations in leaves,and TMg concentration in litters showed an increasing trend with altitude.Total nitrogen(TN),total potassium(TK)and total calcium(TCa)concentrations in both leaves and litters did not vary with altitude.With increasing altitude,leaf and litter C∶P,Fe∶Mn,and C∶Ca showed a trend of increasing first and then decreasing,while Ca∶Mg showed a decline trend.Nutrient resorption efficiency in leaves was not completely consistent with altitude variation.The P and K resorption efficiencies at the altitude of 780 m were the highest,while the N,Fe,and Mn resorption efficiencies were highest at 871 m.The Ca and Mg resorption efficiencies at 1097 m were significantly higher than those at other altitudes.The resorption efficiencies of P,N,and Fe at 1097 m were all negative.The results of redundancy analysis showed strong correlations between leaf nutrient resorption efficiency and stoichiometry.