Association of edaphoclimatic characteristics and variability of condensed tannin content in species from Caatinga

ABSTRACT Condensed tannin (CT) concentrations in plants are influenced by species, plant part, season, growth phase, environmental conditions, disease and defoliation. The objectives of this study were to determine the effects of edaphoclimatic factors on the concentration of CT stored in leaves and bark from Mimosa tenuiflora (Wild.) Poiret and Anadenanthera macrocarpa (Benth.) Brenan., collected at three distinct locations in northeastern Brazil. At each study site, sampling was carried out by randomly selecting five trees, each tree represented one replication and samples of leaves and bark of each plant species was collected. Soil samples were collected near the base of each plant for moisture, physical and chemical analysis. Meteorological data from each month and site were obtained of the INMET automatic station. We conducted a principal components analysis using a multivariate technique to observe the influence of soil and weather on condensed tannin concentration. Overall, Anadenanthera macrocarpa has the least total CT concentration in both plant fraction and site. Our results suggest that soil chemical characteristics, soil moisture and weather explain 76.27% and 75.92% of the variation in CT produced by Mimosa tenuiflora and Anadenanthera macrocarpa, respectively. Condensed tannin concentration in these two species is negatively associated with soil moisture and rainfall, and positively associated with temperature and soil chemical elements.

摘要 植物体内缩合单宁（condensed tannin, CT）的含量受物种、植物部位、季节、生长阶段、环境条件、病害及脱叶程度的影响。本研究旨在探究土壤气候因子对巴西东北部3个不同采样点采集的含羞草（*Mimosa tenuiflora* (Wild.) Poiret）与阔荚合欢（*Anadenanthera macrocarpa* (Benth.) Brenan.）叶片及树皮中储存的缩合单宁含量的影响。在每个研究站点，通过随机选取5株树木开展采样，每株树木作为1次生物学重复，采集各植物物种的叶片与树皮样品。在每株植物基部附近采集土壤样品，用于含水量、物理性质及化学性质分析。从各站点的巴西国家气象研究所（INMET）自动气象站获取月度气象数据。本研究采用多元分析技术中的主成分分析法，以解析土壤与气象因子对缩合单宁含量的影响。整体而言，阔荚合欢在两种植物组分（叶片与树皮）及所有采样位点中的总缩合单宁含量均最低。研究结果表明，土壤化学性质、土壤含水量及气象因子分别解释了含羞草与阔荚合欢缩合单宁含量76.27%和75.92%的变异。上述两种植物的缩合单宁含量与土壤含水量及降雨量呈负相关，与温度及土壤化学元素含量呈正相关。