Growing straight versus growing decumbent: soil quality and allometry in Syagrus glaucescens Becc. (Arecaceae), an endemic and threatened palm of the Espinhaço Mountains, Brazil

Abstract

ABSTRACTSyagrus glaucescens is an endemic palm found in the rupestrian grasslands of the Espinhaço Mountains in southeastern Brazil. It is highly associated with quartzitic soils and exhibits strong intra-specific morphological variation in the different areas where it occurs. Allometric traits were used to verify whether there are any significant differences in the morphological traits between populations of this species located in two distinct areas. In the region of the Serra do Cipó individuals exhibit decumbent stems whereas on the Diamantina Plateau stems are straight and perpendicular to the ground. Soil quality was related to plant morphological traits to test the hypothesis that allometric variation is influenced by soil nutritional differences. Stem shape and size differed significantly among individuals inhabiting the two different regions: individuals in Serra do Cipó were shorter and had fewer leaves compared to individuals found in the Diamantina Plateau. Water retention capacity and nutrient absorption of the soils of the two sites were markedly different. In Serra do Cipó the soils were more acid, with higher aluminum saturation and lower sand content compared to the soils in Diamantina. These traits correlated with stem shape and indicate that soil acidity and aluminum saturation influence the architecture of S. glaucescens.

Keywords

• aluminum saturation
• Diamantina
• phenotypic variability
• rupestrian grasslands
• Serra do Cipó
• soil-plant relationships