Resumo

WANG, QL; LIU, DH  e  YUE, JY. Physiological responses of Allium cepa var. agrogarum L. plants to Cadmium stress. Phyton (B. Aires) [online]. 2016, vol.85, n.2, pp.270-282. ISSN 1851-5657.

This study aimed to determine the effects of different Cd concentrations (0, 1, 10, 100, and 300 µM CdCl₂) on Allium plantlets. To achieve this goal, we examined the (1) dynamics of Cd²⁺ fux in the rhizosphere, (2) partitioning of Cd between roots and leaves, (3) formation of reactive oxygen species (ROS), (4) levels of H₂O₂ and chlorophyll, and (5) translocation of several macro- and micronutrients. A strong net Cd²⁺ influx was observed in the root apex after exposure to 100 µM Cd for 24 h. Exposure to either 1 or 10 µM Cd for 96 h presented no evident influence on root growth. However, treatments with 100 to 300 µM Cd for 72 h significantly inhibited root growth. ROS levels increased in roots and leaves with increasing Cd concentrations. The concentration of photosynthetic pigments, except for carotenoids on day 4, increased with increasing Cd concentrations and treatment duration. Cd accumulation decreased photosynthetic carbon assimilation but exerted no efects on diurnal patterns. Cd accumulated in roots and leaves, but a larger content was detected on roots than on leaves. Several macro- and micronutrients showed tissue- and concentration-specific responses to Cd.

Palavras-chave : Cadmium (Cd) toxicity; Net cadmium flux; ICP; Oxidative stress; Photosynthesis.