Effect of arsenic stress on root morphological parameters and absorption of nutrient elements in ryegrass

Ryegrass was regarded as a plant species with potential for phytoremediation owing to its stronger heavy metal tolerance and accumulate capacities. For exploring the root morphological parameters and absorption of nutrient elements characteristic of ryegrass under arsenic stress, a pot experiment was performed. We studied the effect of 100 mg·kg-1 arsenic (As) stress on root morphological parameters and nutrient elements absorption of perennial ryegrass (Lolium perenne) and annual ryegrass (Lolium multiflorum), Moreover, we aimed to analyze the relationships of arsenic absorption with root morphological parameters and the content of nutrient elements. The results indicated that total length and total surface area of perennial ryegrass were reduced significantly by 47.6% and 46.8%, respectively, as compared with those of annual ryegrass. The absorbing capacity of As of perennial ryegrass root was 1.2 times greater than that of annual ryegrass. As stress promoted the absorption of N/P/K/Mn in two ryegrass species. Perennial ryegrass root had a greater effect on N/P/K absorption, whereas annual ryegrass root had a greater effect on Mn absorption. The root morphological parameters and nutrient absorption of perennial ryegrass was more sensitive to arsenic stress.