The physiological responses of Dicranopteris pedata under different clipping intensities in ionic rare earth mining area of southern China
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 inten-sities,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 dis-mutase played a dominant role in the physiological indicators of D.pedata adversity.Soluble sugar content in D.pe-data was lowest under 100%clipping.Rare earth elements participated in the stress physiological activity of D.pe-data.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.