Physio-Biochemical Responses of Three Aquilegia Species Seedlings to Salt Stress

Abstract

Road deicing salts are widely used during winter in northern China, which makes it essential to choose proper salt-tolerant plant species in urban landscapes. Columbine (Aquilegia) is a herb with high ornamental and commercial values. This study evaluated three Aquilegia species (A. oxysepala, A. parviflora, and A. viridiflora) for salt tolerance by monitoring their germination state under different electrical conductivity (EC) of 0.1 dS·m−1 (distilled water), 1.0 dS·m−1, 2.0 dS·m−1, 3.0 dS·m−1, 4.0 dS·m−1, 5.0 dS·m−1, 6.0 dS·m−1, physio-biochemical responses to different EC of 0.3 dS·m−1 (tap water), 5.0 dS·m−1, and 10.0 dS·m−1. The germination and growth parameters, visual scores, dry weight, leaf stomatal conductance, photosynthetic rate, and chlorophyll contents of three species decreased under salt stress, which was opposite to the changes of electrolyte leakage, malondialdehyde, proline, and soluble sugar contents. Superoxide dismutase and peroxidase activity trend differently among species. These results showed that the germination threshold of three species was 6.0 dS·m−1. A. oxysepala was the most salt-tolerant species, with a tolerance threshold of soil conductivity in 2.83 dS·m−1, followed by A. viridiflora and A. parviflora. Therefore, A. oxysepala is suitable for planting as a ground cover in urban areas where deicing salt is applied.