Elevated atmospheric CO2 concentration (\[CO2\]) increases rice yield, but little is known about effects of \[CO2\] on Zn bioavailability of edible parts of rice, as well as the agricultural practices which can improve micronutrient status of rice under high CO2 environment. By using a Free Air CO2 Enrichment (FACE) facility installed in paddy field, super rice Ⅱyou 084 were grown under two levels of CO2 concentration (ambient and 50% higher than ambient), N application (15 and 25 g/m2), planting density (16 and 24 hills/m2) and foliar Zn application (0% and 02% ZnSO4). At maturity, in milled and brown rice Zn and phytate concentrations were analyzed, molar ratio of phytate to Zn were calculated. The results showed that compared to brown rice, milled rice had much lower Zn concentration, phytate concentration and molar ratio of phytate to Zn. Elevated \[CO2\] significantly decreased Zn concentration of milled and brown rice by 5% and 7%, respectively; Foliar Zn application significantly increased Zn concentration of milled and brown rice by 40% and 63%, respectively. However, the changes of N application and planting density had no effects on rice Zn concentration. Phytate concentrations of milled and brown rice were not affected by either CO2 or Zn treatments, but higher levels of N application and planting density significantly decreased phytate concentration of brown rice by 8% and 6%, respectively. The molar ratios of phytate to Zn in milled and brown rice were significantly increased at elevated \[CO2\] in average of 6% and 7%, but decreased under foliar Zn application by 28% and 40%, respectively. The high levels of N application and planting density had little effects on molar ratio of phytate to Zn in milled rice, but in brown rice,it decreased by 10% and 7%. Our results indicate that the content and bioavailability of micronutrient Zn in edible part of rice Ⅱyou 084 will be lower under future high CO2 environment, but modification of agronomic practice such as ample N application, increase of planting density, especially foliar Zn application during grain filling stage can improve Zn nutrition of rice seeds to various degree.
\[1\]杨连新, 王云霞, 朱建国, 等. 十年水稻FACE研究的产量响应. 生态学报, 2009, 29(3): 14861497.
\[2\]杨连新, 王云霞, 朱建国, 等. 开放空气中CO2浓度增高 (FACE) 对水稻生长和发育的影响. 生态学报, 2010, 30 (6): 15731585.
\[3\]Wang Y X, Frei M, Song Q L, et al. The impact of atmospheric CO2 concentration enrichment on rice quality. Acta Ecol Sin, 2011, 31: 277282.
\[4\]Yang L X,Peng S B. Agronomic avenues to maximize the benefits of rising atmospheric CO2 concentration in the Asian irrigated rice system//Araus J L, Slafer G A. Crop Stress Management and Global Climate Change. CABI Climate Change Series Vol.2. Oxon, UK: CAB, 2011: 3746.
\[5\]WHO. Reducing risks, promoting healthy life//World Health Organization. The World Health Report. Geneva, Switzerland, 2002.
\[6\]Stein A J. Global impacts of human mineral malnutrition. Plant Soil, 2010, 335: 133154.
\[7\]Cakmak I. Enrichment of cereal grains with zinc: Agronomic or genetic biofortification? Plant Soil, 2008, 302: 117.
\[8\]Zhao F J, McGrath S P. Biofortification and phytoremediation. Curr Opin Plant Biol, 2009, 12: 373380.
\[9\]Seneweera S P, Blakeney A, Milham P, et al. Influence of rising atmospheric CO2 and phosphorus nutrition on the grain yield and quality of rice (Oryza sativa cv. Jarrah). Cereal Chem, 1996, 73(2): 239243.
\[10\]Seneweera S P, Conroy J P. Growth, grain yield and quality of rice (Oryza sativa L.) in response to elevated CO2 and phosphorus nutrition. Soil Sci Plant Nutr, 1997, 43: 11311136.
\[11\]Lieffering M, Kim H Y, Kobayashi K, et al. The impact of elevated CO2 on the elemental concentrations of fieldgrown rice grains. Field Crops Res, 2004, 88(2/3): 279286.
\[12\]Yang L X, Wang Y L, Dong G C, et al. The impact of freeair CO2 enrichment (FACE) and nitrogen supply on grain quality of rice. Field Crops Res, 2007, 102(2): 128140.
\[13\]庞静, 朱建国, 谢祖彬, 等. 自由空气CO2浓度升高对水稻营养元素吸收和籽粒中营养元素含量的影响. 中国水稻科学, 2005, 19(4): 350354.
\[14\]Long S P, Ainswoth E A, Leakey A D B, et al. Food for Thought: LowerThanExpected crop yield stimulation with rising CO2 concentrations. Science, 2006, 312: 19181921.
\[15\]Kimball B A, Kobayashi K, Bindi M. Responses of agricultural crops to freeair CO2 enrichment. Adv Agron, 2002, 77: 293368.
\[16\]王云霞, 杨连新, Remy Manderscheid, 等. C4作物FACE (free air CO2 enrichment) 研究进展. 生态学报, 2011, 31 (5): 14501459.
\[17\]任思荣, 朱建国, 李辉信, 等. 大气CO2浓度升高对水稻伤流液中矿质元素的影响. 农业环境科学学报 2007,26(5):1849 1853
\[18\]Lapteva N A. Colorimetric determination of phytate in unpurified extracts of seeds and the products of their processing. AnalBiochem, 1988, 175: 227230.
\[19\]Morris E R, Ellis R. Usefulness of the dietary phytic acid/zinc molar ratio as an index of zinc bioavailability to rats and humans. Biol Trace Elem Res, 1989, 19:107117.
\[20\]Cakmak I, Pfeiffer W H, McClafferty B. Biofortification of durum wheat with zinc and iron. Cereal Chem, 2010, 87: 1020.
\[21\]Cakmak I, Kalayci M, Kaya Y, et al. Biofortification and localization of zinc in wheat grain. J Agric Food Chem, 2010, 58: 90929102.
\[22\]Yang L X, Liu H J, Wang Y X, et al. Impact of elevated CO2 concentration on intersubspecific hybrid rice cultivar Liangyoupeijiu under fully open air field conditions. Field Crops Res, 2009, 112: 715.
\[23\]Yang L X, Liu H J, Wang Y X, et al. Yield formation of CO2enriched intersubspecific hybrid rice cultivar Liangyoupeijiu under fully openair field condition in a warm subtropical climate. Agric Ecosyst Environ, 2009, 129: 193200.
\[24\]Liu H J, Yang L X, Wang Y L, et al. Yield formation of CO2enriched hybrid rice cv. Shanyou 63 under fully openair field conditions. Field Crops Res, 2008, 108: 93100.
\[25\]Meenakshi J V, Johnson N, Manyong V M, et al. How costeffective is biofortification in combating micronutrient malnutrition? An exante assessment. Harvest Plus Working Paper 2. International Food Policy Research Institute (IFPRI), Washington, DC, 2007.
\[26\]Mabesa R L, Impa S M, Grewal D, et al. Contrasting grainZn response of biofortification rice (Oryza sativa L.) breeding lines to foliar Zn application. Field Crops Res, 2013, 149: 223233.
\[27\]齐义涛, 张庆, 周三妮, 等. 结实期叶面施锌对扬麦16号和扬辐麦2号籽料不同部位锌含量的影响. 农业环境科学学报, 2013, 32 (4): 675680.
\[28\]Loennerdal B. Phytic acidtrace element (Zn, Cu, Mn) interactions. Food Sci Technol Int, 2002, 37: 749758.
\[29\]Schlemmer U. Phytate in foods and significance for humans: Food sources, intake, processing, bioavailability, protective role and analysis. Mol Nutr Food Res, 2009, 53: 330375.
\[30\]王慧, 李茂柏, 张建明, 等. 水稻籽粒不同部位植酸含量及其与稻米品质的相关性. 中国水稻科学, 2009, 23 (2): 215218.
\[31\]齐义涛, 周三妮, 张庆, 等. 结实期叶面施锌对小麦籽粒不同部位锌有效性的影响. 农业环境科学学报, 2013, 32(6): 10851091.
\[32\]Marschner P. Mineral Nutrition of Higher Plants (3 ed). San Diego, USA: Academic press, 2011: 149.
\[33\]冯跃, 王伯伦, 王慧新, 等. 不同施肥水平和种植密度对水稻根部性状的影响. 沈阳农业大学学报, 2007, 8: 467471.
\[34\]World Health Organization. Trace element in human nutrition and health. Geneva, 1996.
\[35\]Loladze I. Rising atmospheric CO2 and human nutrition: Towards globally imbalanced plant stoichiometry. Trends Ecol Evol, 2002, 17: 457461.
\[36\]Zhang Y Q, Sun Y X, Ye Y L, et al. Zinc biofortification of wheat through fertilizer applications in different locations of China. Field Crops Res, 2012, 125: 17.
\[37\]Persson D P, Hansen T H , Laursen K H, et al. Simultaneous iron, zinc, sulfur and phosphorus speciation analysis of barley grain tissues using SECICPMS and IPICPMS. Metallomics, 2009, 5: 418426.