Anatomical and biochemical characteristics of Achnatherum splendens (Trin.) Nevski seedlings stressed on Pb2+.

Lead is a heavy metal that usually accumulates in the environment as a hazardous pollutant. Achnatherum splendens (Trin.) Nevski seedlings facilitate the purification and disposal of urban and industrial sewage; however, the detailed mechanism of this phytoremediation is still unknown. In the present study, we investigated the effect of lead (Pb(2+)) stress on the anatomical and biochemical characteristics in A. splendens seedlings using microscopy and proteomic analysis. Our results showed that starch grains accumulate in the cell as the concentration of Pb(2+) increases. Several organelles such as the nucleus, mitochondria, and chloroplasts were found to be damaged as a result of Pb(2+) stress. However, the cell wall and the vacuole compartmentalization could reduce the heavy metal poison. The number of total proteins decreased as Pb(2+) concentration increased. Furthermore, the low molecular weight protein played an important role in resistance to heavy metal Pb(2+) stress. Peroxidase (POD) and amylase activities were still high at concentrations of 200 and 160 mg L(-1) Pb(2+), respectively. The ATPase activity was in the top peak at a concentration of 80-160 mg L(-1) Pb(2+). Thus, these three enzymes were involved in resistance against Pb(2+) stress. The content of proline increased with the increased concentration of Pb(2+). Malondialdehyde (MDA) and soluble sugar peaked at concentrations of 160 and 80 mg L(-1) Pb(2+), respectively. Our results indicated that the last three organic compounds were involved in resistance against Pb(2+) stress.