Agronomy practices aimed at wheat (
Triticum aestivum
L.) grain Zn biofortification are important to alleviate
Zn deficiency in humans, especially for those resource-poor people owing to subsistence on diets dominated by
cereal-based foods with low concentrations and bioavailability of Zn. To promote understanding of source-sink
flow processes affecting biofortification of wheat with Zn, effects of different source/sink manipulations on grain
Zn accumulation by wheat were examined in pot and field at two locations. Treatments included foliar applications
of deionized water, sucrose, ZnSO
4, sucrose + Zn, defoliation, spike shading or partial removal of spikes. Results
showed sucrose + Zn significantly increased grain Zn concentration more than Zn alone. Grain Zn concentration
with sucrose + Zn averaged 66 mg kg
-1 for ‘Kenong 9204’ and 59 mg kg
-1 for ‘Liangxing 99’ in pot, and ranged from
42 to 58 mg kg
-1 for ‘Liangxing 99’, ‘Jinan 17’, ‘Jimai 20’, ‘Jimai 22’, and ‘Luyuan 502’ under field, approaching
the field-grown target 60 mg kg
-1 proposed by World Health Organization. Molar ratios of phytic acid/Zn and
phytic acid × Ca/Zn of ‘Jinan 17’, ‘Jimai 20’ or ‘Luyuan 502’ with sucrose + Zn were reduced to be < 15 and <
200, respectively, suggesting higher Zn bioavailability. Defoliation or spike shading decreased grain weight, Zn
concentration and content. It is concluded that grain Zn accumulation of wheat can be affected by the source-sink
relationship of Zn and/or carbohydrate, and the foliar spray ‘sucrose + Zn’ is recommended for increasing
concentration and bioavailability of Zn in wheat grains.
