Research ArticleECOLOGY

Carbon dioxide (CO2) levels this century will alter the protein, micronutrients, and vitamin content of rice grains with potential health consequences for the poorest rice-dependent countries

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Science Advances  23 May 2018:
Vol. 4, no. 5, eaaq1012
DOI: 10.1126/sciadv.aaq1012
  • Fig. 1 Average reduction in grain protein at elevated relative to ambient [CO2] for 18 cultivated rice lines of contrasting genetic backgrounds grown in China and Japan using FACE technology.

    A country by [CO2] effect on protein reduction was not significant (P = 0.26). Bars are ±SE. *P < 0.05 and **P < 0.01 (see Methods for additional details).

  • Fig. 2 Average reduction in grain micronutrients, iron (Fe), and zinc (Zn) concentration at elevated relative to ambient [CO2] for 18 cultivated rice lines of contrasting genetic backgrounds grown in China and Japan using FACE technology.

    A country by [CO2] effect was not significant for either micronutrient [P = 0.17 and 0.10 for iron (Fe) and zinc (Zn), respectively] so data from both locations are shown. Bars are ±SE. *P < 0.05 and **P < 0.01 for a given cultivar. CO2; **P < 0.01 is based on all cultivars (see Methods for additional details).

  • Fig. 3 CO2-induced reductions in vitamins B1 (thiamine), B2 (riboflavin), B5 (pantothenic acid), and B9 (folate) by cultivar.

    No significant effect was observed for vitamin B6 (pyridoxine), and results are not shown. Analysis was conducted only for the China FACE location. Bars are ±SE. *P < 0.05 and **P < 0.01 for a given cultivar. CO2; **P < 0.01 is based on all cultivars (see Methods for additional details).

  • Fig. 4 Projected [CO2]-induced deficits in protein and minerals (Fe and Zn) and cumulative changes in vitamin B and cumulative changes in vitamin E derived from rice as a function of GDP per capita.

    Data are based on 2011/2013 FAO food balance sheets for rice consumption and 2011/2013 World Bank estimates of GDP per capita per country.

  • Fig. 5 Average change in vitamin concentration (as percentage) in response to anticipated, relative to current, [CO2] ±SE as a function of the ratio of the molecular weight of nitrogen (N) to the molecular weight of the vitamin.

    There was a highly significant correlation between the amount of N present in the vitamin and the overall decrease or increase in response to higher [CO2].

  • Table 1 Characteristics of rice lines used.
    CultivarOriginSubgroupComments
    86Y8ChinaHybridBred for disease-resistance; high ripening rate
    BekoaobaJapanJaponicaBred for lodging resistance, used in silage
    Hokuriku 193JapanIndicaHigh-yielding, blast-resistant
    HoshiaobaJapanJaponicaCultivar used for silage and bioenergy
    IR72PhilippinesIndicaSemi-dwarf, often used as check cultivar
    KoshihikariJapanJaponicaWidely grown in Japan
    LemontUnited StatesJaponicaSemi-dwarf grown in Mississippi Delta
    Milyang 23KoreaIndicaHigh-yielding, cadmium accumulator
    MomiromanJapanJaponicaMedium grain, high-yielding variety
    NipponbareJapanJaponicaGenome-sequenced
    Liang You 084ChinaHybridGrown extensively in southeast China
    TakanariJapanIndicaWidely grown in Japan
    Wuyunjing 21ChinaJaponicaGrown extensively in East China
    Wuyunjing 23ChinaJaponicaGrown extensively in East China
    Yangdao 6 haoChinaIndicaGrown extensively in East and Central China
    YliangyouChinaHybridRecently introduced (2008) hybrid line
    Yongyou 2640ChinaHybridWidely planted in lower Yangtze River
    Zhonghua 11ChinaJaponicaDisease-resistant line used in breeding

Supplementary Materials

  • Supplementary material for this article is available at http://advances.sciencemag.org/cgi/content/full/4/5/eaaq1012/DC1

    table S1. Elution procedures for vitamin B and vitamin E.

    table S2. Compound parameters for vitamins B1, B2, B5, B6, B9 and E.

    fig. S1. As for Fig. 3, but for vitamin E (α-tocopherol) (see Methods for additional details).

  • Supplementary Materials

    This PDF file includes:

    • table S1. Elution procedures for vitamin B and vitamin E.
    • table S2. Compound parameters for vitamins B1, B2, B5, B6, B9 and E.
    • fig. S1. As for Fig. 3, but for vitamin E (α-tocopherol) (see Methods for additional details).

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