Root morphology and leaf gas exchange in Peltophorum dubium (Spreng.) Taub. (Caesalpinioideae) exposed to copper-induced toxicity

Abstract Excess copper (Cu) in the soil causes physiological and morphological changes in plants. The objective of this research was to evaluate root morphology and photosynthetic responses in Peltophorum dubium plants exposed to excess Cu. Growth, leaf gas exchange, root morphology and bioaccumulated Cu in the different plant tissues were evaluated. Excess Cu reduced plant height and diameter, and altered root system morphology in P. dubium . Length, surface area, mean diameter and root volume also decreased with excess Cu treatment. The effect of excess Cu on roots was observed by the inhibited development of very fine roots. In general, accumulation of Cu occurred mainly in the root system, and this heavy metal in excess inhibited the growth of P. dubium . As a consequence of Cu toxicity, there was a reduction in root and shoot dry weight, as well as significant affects on photosynthesis (A and A max ) and transpiration (E) that were dependent on Cu concentration.