叶面施用不同形态锌化合物对稻米锌浓度及有效性的影响

Effect of Foliar Application of Different Zn Compounds on Zn Concentration and Bioavailability in Brown Rice

2014年土培条件下,以日本晴、L81和L71为供试材料,开花及花后1周叶面喷施硫酸锌、柠檬酸锌、葡萄糖酸锌和EDTA二钠锌(Zn2+浓度均为0.2%,以喷施等量清水为对照),研究叶面喷施不同形态锌化合物对稻穗不同部位糙米锌浓度及有效性的影响。结果表明,稻穗不同部位糙米锌浓度差异显著,其中稻穗上部糙米锌浓度显著大于稻穗中部和下部,植酸、植酸与锌摩尔比则相反,不同处理趋势一致。与不施锌相比,硫酸锌、柠檬酸锌、葡萄糖酸锌和EDTA二钠锌使所有品种糙米锌浓度平均分别增加33%、31%、26%和27%,其中锌处理对稻穗上、中部糙米锌浓度的影响显著大于稻穗下部,供试材料中以日本晴的响应最大。锌处理对糙米植酸浓度影响较小,但对植酸与锌摩尔比影响较大。与对照相比,硫酸锌、柠檬酸锌、葡萄糖酸锌和EDTA二钠锌使所有品种糙米植酸与锌摩尔比平均分别下降25%、24%、22%和18%,其中稻穗上部和中部的降幅大于稻穗下部,日本晴和L71的降幅大于L81;锌处理×品种和锌处理×品种×部位间互作均达显著水平。以上数据说明,水稻籽粒生长早期喷锌处理可大幅增加糙米锌浓度及其生物有效性,增幅因锌化合物、供试品种以及籽粒在稻穗上的着生部位(以强势粒响应更大)而异。

Zinc（Zn）biofortification through foliar Zn application is an attractive strategy to reduce Zn deficiency.Four Zn compounds were applied through foliar spray to three rice varieties at flowering and one week after flowering under field conditions.The concentrations of Zn and phytic acid in brown rice were measured.The results showed that Zn concentration in grains from different parts of a panicle varied significantly,with Zn concentration of grains from upper part of a panicle being higher than that of middle or lower parts.In contrast,phytic acid or the molar ratio of phytic acid to Zn showed the opposite trend.Compared with CK（water spray）,foliar application of ZnSO4,Zn-citrate,Zn-gluconate and Zn-EDTA increased Zn concentration by 33%,31%,26% and 27%,respectively.The grains at upper or middle parts of a panicle were affected much more than that at lower part.Nipponbare was more sensitive to Zn application than other varieties.Zinc treatment had little effect on the concentration of phytic acid.Averaged across all varieties,the molar ratio of phytic acid to Zn in brown rice was reduced by 25%,24%,22% and 18% through foliar application of ZnSO4,Zn-Citrate,Zn-Gluconate and Zn-EDTA,respectively.The reduction was greater in the grains from upper or middle parts than lower part of a panicle.The reduction in Nipponbare or L71 was greater than that in L81.Significant Zn×variety interaction and Zn×variety ×position interaction were detected.In conclusion,foliar Zn application at early grain growing stage significantly increased Zn concentration and bioavailability,and the increment varied with Zn compound,genotype and grain position,with superior spikelets being more susceptible.