Abstract: 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.

Key words: Zanthoxylum planispinum var. dintanensis, stoichiometry, nutrient resorption, altitude,  karst rock desertification