Rare earth element transfer from soil to navel orange pulp (Citrus sinensis Osbeck cv. Newhall) and the effects on internal fruit quality

PLoS One. 2015 Mar 25;10(3):e0120618. doi: 10.1371/journal.pone.0120618. eCollection 2015.

Abstract

The effects of soil rare earth element (REE) on navel orange quality and safety in rare earth ore areas have gained great attention. This study investigated the transfer characteristics of REE from soil to navel orange pulp (Citrus sinensis Osbeck cv. Newhall) and examined the effects of soil REE on internal fruit quality in Xinfeng County, Jiangxi province, China. Path analysis showed that soil REE, pH, cation exchange capacity (CEC), and Fe oxide (Feox) significantly affected pulp REE concentrations. A Freundlich-type prediction model for pulp REE was established: log[REEpulp] = -1.036 + 0.272 log[REEsoil] - 0.056 pH - 0.360 log[CEC] + 0.370 log[Feox] (n = 114, R2 = 0.60). From the prediction model, it was inferred that even when soil REE and Feox were as high as 1038 mg kg-1 and 96.4 g kg-1, respectively, and pH and CEC were as low as 3.75 and 5.08 cmol kg-1, respectively, pulp REE concentrations were much lower than the food limit standard. Additionally, soil REE levels were significantly correlated with selected fruit quality indicators, including titratable acidity (r = 0.52, P < 0.01), total soluble solids (r = 0.48, P < 0.01) and vitamin C (r = 0.56, P < 0.01). Generally, under routine methods of water and fertilization management, the cultivation of navel oranges in rare earth ore areas of south China with soil REE ranging from 38.6 to 546 mg kg-1 had improved in internal fruit quality.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Ascorbic Acid / chemistry
  • Citrus sinensis / chemistry*
  • Citrus sinensis / metabolism
  • Ferric Compounds / chemistry
  • Fruit / chemistry
  • Fruit / metabolism
  • Hydrogen-Ion Concentration
  • Ion Exchange
  • Linear Models
  • Mass Spectrometry
  • Metals, Rare Earth / analysis*
  • Soil / chemistry*

Substances

  • Ferric Compounds
  • Metals, Rare Earth
  • Soil
  • ferric oxide
  • Ascorbic Acid

Grants and funding

This work was supported by the GanPo 555 Talents Program of Jiangxi Province, China, URL: http://www.jiangxi.gov.cn/ and the Knowledge Innovation Program of Chinese Academy of Sciences (ISSAS Y112000016), URL: http://www.cas.cn/, author received the funding: XXW. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.