Open Access

ARTICLE

Physiological responses of Allium cepa var. agrogarum L. plants to Cadmium stress

Wang QL, DH Liu, JY Yue

Tianjin Key Laboratory of Animal and Plant Resistance, Tianjin Normal University, Tianjin, 300387, P.R. China.

Address correspondence to: Jieyu Yue, Tel: 86-22-2376 6823, Fax: 86-22-2376 6359, e-mail:

Phyton-International Journal of Experimental Botany 2016, 85(all), 270-282. https://doi.org/10.32604/phyton.2016.85.270

Abstract

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⁺ flux 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 effects 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.

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