Differences in stomatal density (SD) and stomatal index (SI) are associated with the conditions of the environment in which they are distributed. Mimosa species are important elements in different plant communities, yet knowledge of the ecological implications of its stomatal characteristics is scarce. For this reason, SD and SI were determined in seven Mimosa species from different environments in this study. Five individuals per species were selected, and a sample of leaflets was obtained from each. Fifteen mature leaflets per individual were then extracted and observed by optical microscopy. SD, SI, epidermal cell density (ECD), and guard cell length (GCL) values were obtained. Differences between species were analyzed through a balanced analysis of variance test, and the correspondence between the stomatal characteristics and 21 climate variables was determined by canonical correspondence analysis. The species differed in all evaluated characteristics. It should be noted that only M. affinis showed differences between the leaflet surfaces. Both DE and ECD were negatively associated with altitude and solar radiation and positively with temperature and precipitation. SI was explained by temperature and seasonality of precipitation, and GCL by temperature oscillation and seasonality of precipitation. The results suggest that the stomatal characteristics of the leaflets confer resistance in the species to alterations in environmental conditions.

气孔密度（SD）和气孔指数（SI）的差异与其分布的环境条件有关。含羞草物种是不同植物群落的重要组成部分，但对其气孔特征的生态影响的了解却很少。因此，本研究测定了来自不同环境的七种含羞草物种的 SD 和 SI。每个物种选择了五个个体，并从每个个体中获取了传单样本。然后提取每个个体十五张成熟的小叶并通过光学显微镜观察。获得 SD、SI、表皮细胞密度 (ECD) 和保卫细胞长度 (GCL) 值。通过平衡方差分析检验分析物种间差异，并通过典型对应分析确定气孔特征与21个气候变量的对应关系。该物种在所有评估的特征上都不同。应该指出的是，只有M. affinis显示出小叶表面之间的差异。DE 和 ECD 均与海拔高度和太阳辐射呈负相关，与温度和降水呈正相关。SI用温度和降水季节性解释，GCL用温度波动和降水季节性解释。结果表明，小叶的气孔特征赋予该物种对环境条件变化的抵抗力。