南方离子型稀土矿区不同刈割强度下芒萁的生理响应

The physiological responses of Dicranopteris pedata under different clipping intensities in ionic rare earth mining area of southern China

稀土污染已成为南方离子型稀土矿区的关键环境问题。为揭示不同刈割强度处理下芒萁的超补偿生长效应以及芒萁的耐刈性,以南方离子型稀土矿区长汀为研究区,将芒萁(Dicranopteris pedata)按面积比例分100%、75%、50%、25%、不刈割共5个强度进行刈割,测定芒萁的生物量、逆境生理指标和稀土元素含量。结果显示,芒萁均发生超补偿生长;样方内刈割后的新生芒萁和残留芒萁的酶促保护系统和渗透调节物质都发生改变,其中脯氨酸含量与芒萁生物量密切相关,超氧化物歧化酶在芒萁逆境生理指标中起主导作用,100%刈割下可溶性糖含量最低;稀土元素参与了芒萁的逆境生理活动。综上所述,刈割可以诱导芒萁超补偿生长,同时也对芒萁造成了胁迫,100%刈割达到胁迫阈值不利于芒萁的养分积累,样方内残留未刈割芒萁也对刈割产生响应,稀土元素可以诱导芒萁耐刈性提高。

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.