Effects of Cadmium and Lead on Plant Growth and Content of Heavy Metals in Arugula Cultivated in Nutritive Solution

Abstract

A greenhouse assay using an arugula (Eruca sativa L.) hydroponics system was carried out to evaluate the following effects of increasing amounts of cadmium and lead in nutritive solution: (a) production; (b) translocation of cadmium (Cd) and lead (Pb) throughout the plants; (c) possible interactions of Cd and Pb with other mineral elements, transition metals, essential to plants; (d) tolerance limits to Cd and Pb with regard to production; and (e) chelating interaction of Cd and Pb with root substances. The absorption of Cd and Pb increased with increasing dosages in solution. Roots accumulated larger amounts of metals than shoots. Plants develop better with less than 0.025 mg L⁻¹ of Cd, with a damaging Cd concentration of 1 mg L⁻¹. The tolerable Pb concentration was up to 10 mg L⁻¹. Cadmium and Pb translocate poorly in plants and their deleterious effect is due to the deposit of very stable chelates in roots.

Keywords:

• Arugula
• cadmium
• hydroponics
• lead
• uptake

Acknowledgment

CNPq (National Council of Research) (to C. M. P. A. and M. P. F.) and CAPES (Coordination for Improvement of Higher Level Personnel) (to A. R. R. B.) are gratefully acknowledged for the fellowships and the studentships (to A. S. A. and M. G. C.).