不同熟期玉米品种和氮肥种类对植株锌营养和籽粒锌累积的影响

Effects of Different Cultivarswith Varied Maturation Periods and Different Nitrogen Formson Shoot Zn Nutrition and Grain Zn Accumulation of Summer Maize

田间条件下研究不同熟期玉米品种(登海605为晚熟品种,鲁单981为早熟品种,分别简写为DH605和LD981)和氮肥种类(尿素、硫酸铵、硝酸铵钙)对植株锌(Zn)营养和籽粒锌累积的影响。结果表明,不同氮肥种类对吐丝前和吐丝后植株锌吸收、转运及籽粒锌浓度均无显著影响。LD981吐丝前地上部锌累积量较DH605低17.7%,而吐丝后锌吸收量较DH605高出110.7%,最终导致成熟期锌累积量较DH605高出18.2%,籽粒锌浓度较DH605高出10.1%。两个玉米品种籽粒锌累积主要来源不同:DH605灌浆期内锌转移量为0.97mg/株,锌转移效率为35.2%,锌输出量对籽粒锌累积的表观贡献率为51.4%,而花后锌吸收对籽粒锌累积贡献率为48.6%;相反,LD981灌浆期内锌几乎没有从营养器官向籽粒转移,籽粒高达95.4%的锌累积来自吐丝后锌吸收。吐丝后锌吸收量与两个玉米品种籽粒锌浓度均呈显著正相关关系,且与LD981籽粒干重也呈显著正相关关系。以上结果表明,对于锌转移效率低但吐丝后锌吸收能力强的玉米品种LD981,氮锌配合施用或土施尿素锌有利于维持整个生育期玉米对锌的需求以实现最大的籽粒干重和籽粒锌浓度;对于锌转移效率较高的品种DH605,土施锌肥结合花后叶面喷施锌肥是提高玉米籽粒锌浓度的有效措施。

Filed experiment was conducted to investigate the effects of different maize cultivars with varied maturation periods(DH605 and LD981 corresponding to late-maturating cultivar and early-maturating cultivar, respectively) and different N forms(urea, ammonium sulfate and calcium ammonium nitrate) on the shoot Zn nutrition and grain Zn accumulation. The results showed that different N forms had no significant effects on the pre-silking and post-silking shoot Zn accumulation and grain Zn concentration. Compared with DH605, LD981 had 17.7% lower pre-silking Zn accumulation, but 110.7% higher post-silking Zn accumulation, and finally 18.2% higher shoot Zn accumulation and 10.1% higher grain Zn concentration at maturity stage. The sources of grain Zn accumulation were different between the two cultivars. For DH605, during grain-filling period, the Zn remobilization amount was 0.97 mg per plant, the Zn remobilization efficiency was 35.2%, and the percentage of grain Zn provided by remobilization of the pre-silking Zn stores accounted for 51.4%, while that of post-silking Zn uptake accounted for 48.6%. By contrast, for LD981, there had almost no Zn transfer from vegetative organs to grains. However, up to 95.4% of grain Zn accumulation originated from the post-silking Zn uptake. Post-silking Zn uptake significantly positively correlated with grain Zn concentration of the two cultivars and grain dry weight of LD981. These results suggested that for LD981 with lower Zn remobilization efficiency but higher post-silking Zn uptake, the combination of N and Zn fertilizers or soil application of Zn-enriched urea were in favour of more and season-long Zn supply for maximum grain dry weight and grain Zn concentration. For DH605 with higher Zn remobilization efficiency, the combination of soil and foliar applications of Zn fertilizer might be an economical method for improving grain Zn concentration.