关键词: 植物功能性状, 早衰, 顶坛花椒, 干热河谷石漠化区

Abstract: To understand the effects of recession on leaf functional traits of Zanthoxylum planispinum var. dintanensis and its recession response strategy, we investigated the leaf functional traits and soil physicochemical properties of normal and prematurely declining Z. planispinum var. dintanensis plantations. The results showed that specific leaf area, leaf phosphorus concentration, stable carbon isotope abundance, and leaf dry matter content were increased under premature senescence. The concentrations of organic carbon, nitrogen, potassium, and stable nitrogen isotopein leaves were decreased by premature senescence. There were significant differences in specific leaf area and stable carbon isotope abundance between normal and prematurely declining plantations. The correlations among leaf factors of prematurely declining plantation were weaker than that in normal plantation. The results of relative importance analysis and redundancy analysis revealed that soil moisture had the strongest effect on leaf functional traits such as specific leaf area and stable carbon isotope abundance in Z. planispinum var. dintanensis, followed by nitrogen, potassium, and calcium concentrations. Limited elements of normal and prematurely declining Z. planispinum var. dintanensis varied with phenological stage. The premature declining caused the reduction of nitrogen and phosphorus use efficiency of Z. planispinum var. dintanensis. Z.planispinum var. dintanensis would further reduce specific leaf area to improve its water use efficiency but maintain leaf dry matter content. These findings may provide a scientific basis for the maintenance of ecosystem stability and the improvement of yield and quality of Z. planispinum var. dintanensis.

Key words: plant functional trait, premature senescence, Zanthoxylum planispinum var. dintanensis, dry-hot valley rocky desertification area.