Correlations of Arsenic and Nutrient Elements in Different Tissues of Perennial Ryegrass Under Arsenic Stress

The objectives of this study were to investigate the growth and nutrient absorption in different tissues of perennial ryegrass under several levels of As stress, and to determine the relationships between absorption As and nutrient elements. As treatments at 0, 5, 10, 25, and 50 mu M were applied to perennial ryegrass in hydroponic systems, and As and nutrient absorption in the mature leaves, expanded leaves, emerging leaves, and roots were determined. The effects of P, Ca, and Mg on the growth and As absorption of perennial ryegrass under As stress were also investigated. The biomass of the different tissues of perennial ryegrass decreased when the As concentration was greater than 5 mu M. The As content was higher in roots relative to leaves regardless of As concentrations in nutrient solution, and leaf As content was greatest in the mature leaves and least in the emerging leaves. The As treatment reduced N, P, Ca, and Mg absorption in different tissues. A positive correlation of As content was found with the Mn content in the roots and all three kinds of leaves. The N, P, and K contents in the leaves were greatest in the emerging leaves and least in the mature leaves. The P, Ca, and Mg application decreased the As absorption of As-challenged perennial ryegrass. Our results indicated that As stress treatment reduced N, P, Ca, and Mg absorption and the As absorption was associated with leaf age and also levels of nutrients. Proper application of mineral nutrients may reduce As absorption of perennial ryegrass.