Abstract: The present study is aimed at comparing the differences in growth responses and chlorophyll fluorescence characteristics between exotic invasive species Plantago virginica and native species P.asiatica under various concentrations of Al³⁺ stress (100, 500, 800 and 2 000 mg·L^-1) along with different durations (0, 10, 20 and 30 d). The results showed that root/shoot ratio increased slightly under low concentration of aluminum (100 mg·L^-1) and began to decrease significantly at over moderate concentration (500 mg·L^-1); leaf chlorophyll a and chlorophyll b showed less change under low concentration of aluminum, but decreased obviously with the increases in Al³⁺ concentration and treatment duration. Measurements of chlorophyll fluorescence parameters revealed that F_v/F_m, Φ_PSⅡ and F_v/F_o increased slightly under low concentration of aluminum, and decreased obviously with the increases in Al³⁺ concentration and duration. The decreases in root/shoot ratio, chlorophyll a and chloraphyll b, F_v/F_m,Φ_PSⅡ and F_v/F_o of P.virginica was less than those of P.asiatica, indicating that the exotic invasive P.virginica had greater potential to alleviate aluminum stress through the mechanism of physiological defense, compared with the native P.virginica.

Key words: aluminum stress, Plantago virginica, P.asiatica, growth, chlorophll content, chlorophll fluorescence