Impacts of Combination of Foliar Iron and Boron Application on Iron Biofortification and Nutritional Quality of Rice Grain

ABSTRACT

To increase iron (Fe) concentration in edible portions of staple food crops, an agronomic approach via foliar Fe-containing solutions might be sustainable and economical strategy; however, little information is available in the literature. So the present work was carried out to examine the effects of Fe in association with boron (B) foliar fertilization on Fe biofortification and the nutritional quality of rice (Oryza sativa L.) grain. The work was conducted in 2006 at the research experiment station at Zhejiang University on japonica rice ‘Bing 98110’ planted on a silty loam soil in pots. The following spray treatments were performed at rice anthesis: (1) control (the deionized water spray); (2) 0.1% (w/v) FeSO₄ · 7H₂O; (3) 0.1% (w/v) Fe(II)-AA (Complex of 0.1% FeSO₄ · 7H₂O and 0.4% compound amino acids; 18.6% N); (4) 0.2% (w/v) H₃BO₃ (boric acid, 17.5% B); (5) combined spray of 0.1% (w/v) FeSO₄ · 7H₂O and 0.2% (w/v) H₃BO₃; (6) combined spray of 0.1% (w/v) Fe(II)-AA and 0.2% (w/v) H₃BO₃. Foliar Fe and B complex application did biofortify Fe concentration and other measured nutritive values in polished rice. Compared to the control, Fe concentration in seed increased significantly 18.9% with the combination of foliar Fe(II)-AA and B, Zn content increased significantly 26.7%, and protein and total 16 amino acids, such as lysine, threonine, and arginine that were essential for human nutrition as well as glutamic acid, aspartic acid, valine, leucine, and phenylalanine, etc., also increased markedly by 30.9% and by 37.0%, respectively.

Keywords:

• iron
• boron
• foliar application
• rice (Oryza sativa l.)
• protein
• amino acids
• nutritional quality
• human health

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ACKNOWLEDGMENTS

The study was funded by HarvestPlus-China Program (No. 8022), and National Natural Science Foundation of China (No. 30370838). And we thank Yang Xingfei for her help on the experimental preparation and Hu Guoxiang for his help on the samples determination.