磷肥对甜玉米籽粒植酸和锌有效性的影响

为明确磷肥对甜玉米籽粒营养特性的影响,利用不同品种的磷肥定位试验以及磷肥梯度水平试验,探讨甜玉米籽粒植酸、磷(P)、锌(Zn)含量及Zn有效性的时间(不同灌浆期)和空间(果穗上、中、下部;籽粒果皮、胚乳和胚)变化及其对外源磷肥的响应特性。试验结果表明,甜玉米籽粒的P和植酸含量随磷肥用量的增加而增加,Zn含量及其有效性则呈现下降趋势。磷肥投入对吐丝后16～24 d籽粒的植酸、P和Zn的积累(mg plant^–1)的影响最为显著,而对不同灌浆时期Zn有效性均表现出抑制效应。在中磷水平下,果穗不同穗位籽粒植酸(g kg^–1)和Zn有效性的差异并不显著。高磷水平显著提高了中、下部果穗植酸的含量,但对不同穗位籽粒Zn含量和Zn有效性均存在抑制效应。对籽粒内不同部位(果皮、胚乳和胚)进行比较,植酸、P以及Zn含量均以胚中含量最高,积累量占比则以胚乳中最高;而Zn有效性以胚中最高。高磷处理可显著提高籽粒内不同部位植酸和磷含量,降低Zn含量及其有效性。综上,合理磷肥施用可促进籽粒Zn积累,而过量磷肥投入会显著增加不同灌浆时期,以及胚乳和胚中的植酸含量和积累量...

Effects of phosphorus fertilizer on kernel phytic acid and zinc bioavailability in sweet corn

To clarify the effects of phosphorus fertilizer on nutritional characteristics of sweet corn kernels,the temporal(different filling stages)and spatial(upper,middle,and lower cob;kernel skin dregs,endosperm and embryo)variations of phytic acid(PA),phosphorus(P)and zinc(Zn)contents and Zn bioavailability of sweet corn kernels and their responses to exogenous phosphorus fertilizer were investigated using filed phosphorus fertilizer experiment(P fertilizer location experiment for sweet corn genotypes and P fertilizer level experiment).The results were as follows:P fertilizer mainly inhibited Zn bioavailability by suppressing Zn concentration in sweet corn kernels,and increased PA concentrations concurrently.P fertilizer input showed significant effects on the accumulation of PA,P,and Zn(mg plant(^-1))after 16-24 days of silking,while inhibitory effects were detected on Zn bioavail-ability at different kernel filling stages.There was no significant difference in the kernel of PA(g kg^-1)and zinc bioavailability among different cob positions under medium P treatment.However,the high P level significantly improved the accumulation of PA in the middle and lower cob,while the inhibitory effect was found on the kernel of Zn concentration and Zn bioavailability at all cob positions.Among different parts of the kernel(skin dregs,endosperm,and embryo),the concentrations of PA,P,and Zn were the highest values in the embryo and their accumulation were the highest value in the endosperm,while Zn bioavailability was also the highest in the embryo.High P treatment significantly increased PA and P concentrations and decreased Zn concentration and its bioavailability at different kernel positions.Hence,optimized phosphorus fertilizer application could promote kernel Zn accumulation,while excessive P fertilizer input significantly increased PA accumulation at different filling stages,as well as in the endosperm and embryo,and eventually had a significant inhibitory effect on kernel Zn bioavailability in sweet corn at differ-ent cob and kernel positions.This study provides a theoretical reference for the biofortification of Zn in sweet corn seeds.