Abstract: Rare earth pollution has become a key environmental issue in ionic rare earth mining areas, southern China. We investigated the over-compensatory growth effect and the clipping tolerance of Dicranopteris pedata under different clipping intensities in a southern ionic rare earth mining area of Changting. There were five clipping intensities, 100%, 75%, 50%, 25%, and no clipping. The biomass, physiological indicators of adversity and rare earth element content of D. pedata were measured. The results showed there was over-compensatory growth of D. pedata in all clipped plots. The enzymatic protection system and osmoregulatory substances were changed in both new-born and residual D. pedata after clipping. Proline content was closely related to D. pedata biomass. Superoxide dismutase played a dominant role in the physiological indicators of D. pedata adversity. Soluble sugar content in D. pedata was lowest under 100% clipping. Rare earth elements participated in the stress physiological activity of D. pedata. In summary, clipping induced over-compensatory growth and caused stress to D. pedata. 100% clipping reached the stress threshold of D. pedata and was unfavorable for nutrient accumulation. Residuals after clipping responded to clipping. Rare earth elements can induce an increase in clipping tolerance of D. pedata.

Key words: rare earth, Dicranopteris pedata, clipping, compensatory growth, stress resistance