Growth and physiological responses of Lolium multiflorum to aluminum stress

We used a pot experiment to determine physiological and growth indicators of Lolium multiflorum Lam. under Al³⁺ stress (0, 100, 200, 300, 400, 500 mg/kg). Results showed that aluminum stress inhibited the growth and biomass accumulation of ryegrass, with higher Al³⁺ content resulting in stronger inhibition. When Al³⁺ content in the soil was 500 mg/kg, plant height and shoot dry weight were significantly inhibited; however, when Al³⁺ content was 100 mg/kg, root length and root dry weight were significantly inhibited. Furthermore, chlorophyll-a, chlorophyll-b, and total chlorophyll in the leaves decreased with the increase in Al³⁺ concentration. When Al³⁺ content was 500 mg/kg, chlorophyll-a and chlorophyll-b decreased by 56.81% and 46.57%, respectively. However, soluble sugar content, free proline content, MDA content, and SOD activity in the above-ground shoot and below-ground root systems increased with the increase in Al³⁺ concentration; however, these four indicators were higher in the shoot than root system.