Effects of lanthanum on growth and accumulation in roots of rice seedlings

Hormetic effects on the growth were found in the roots of rice (Oryza sativa L. cv. Shengdao 16) exposed to increasing concentrations of La3+ (0.05, 0.1, 0.5, 1.0, and 1.5 mmol/L). The results indicated that La3+ promoted the growth of rice roots at 0.05 mmol/L, but inhibited the growth at 1.0 and 1.5 mmol/L La3+ after 13 days of exposure. Transmission electron microscope showed that La3+ was mainly deposited in the cell walls of the roots. In addition, the accumulation of K, Mg, Ca, Na, Fe, Mn, Zn, Cu, and Mo in the roots was also affected with the exposure of different La3+ treatments. It showed that La3+ affected the nutritional status of roots and further regulated the growth of rice.