叶面喷施硒肥对甜玉米籽粒富硒、重金属含量及产量的影响

Effects of foliar spraying of selenium fertilizer on selenium-enriched content, heavy metal content and yield of sweet corn grain

【目的】探索外源施硒对鲜食甜玉米籽粒硒含量、重金属含量、品质及产量的影响,为鲜食甜玉米生产中合理使用硒肥提供参考依据。【方法】以甜玉米品种桂甜612和硒肥"锌硒葆"为试验材料,采用裂区设计,设3个叶面喷施期(拔节期、大喇叭口期、抽雄期)主处理和6个硒肥浓度[0(CK)、0.66、0.80、1.00、1.33和2.00 g/L]副处理,在甜玉米吐丝授粉23 d后测量籽粒中硒、镉、砷含量和籽粒糖度及鲜穗产量。【结果】不同时期喷施硒肥,鲜食甜玉米籽粒硒含量均随硒肥浓度的增加而增加,其中大喇叭口期和抽雄期叶面喷施硒肥可显著(P<0.05)或极显著(P<0.01)提高甜玉米籽粒硒含量。不同时期喷施不同浓度硒肥均能提高甜玉米籽粒糖度,其中拔节期、大喇叭口期喷施0.80～1.00 g/L硒肥的增甜效果较佳。拔节期、大喇叭口期喷施不同浓度硒肥处理的籽粒镉含量和砷含量均高于或等于CK,抽雄期的镉含量低于CK。随硒肥浓度的增加,拔节期的鲜穗产量呈逐渐下降趋势,大喇叭口期和抽雄期的鲜穗产量呈先升高后降低的变化趋势,其中大喇叭口期叶面喷施0.80～1.00 g/L硒肥的增产效果最佳,高浓度(2.00 g/L)硒肥则引起叶面灼伤而造成减产。【结论】适宜生育期叶面喷施适当浓度的硒肥不仅可提高甜玉米的籽粒硒含量、改善甜度口感,还可提高其鲜穗产量,其中以甜玉米大喇叭口期叶面喷施硒肥"锌硒葆"0.80～1.00 g/L的效果最佳。硒肥是否对甜玉米重金属含量产生影响与硒肥喷施时期有关。

【Objective】The effects of exogenous selenium spraying on selenium and heavy mental contents,quality and yield of fresh-eating sweet corn grain were explored in order to provide scientific reference for reasonable use of selenium fertilizer in the production of fresh-eating sweet corn.【Method】Sweet corn variety Guitian 612 and selenium fertilizer Xinxibao were used as the experimental material. Three foliage spraying stages(jointing stage,large bell stage and tassel stage)were used as the main treatments,and six selenium fertilizer concentrations[0(CK),0.66,0.80,1.00,1.33 and2.00 g/L]were used as secondary treatments. The selenium,cadmium and arsenic contents,the sweetness and fresh ear yield of sweet corn grain were determined 23 d after sweet corn silking and pollination.【Result】The selenium content in fresh-eating sweet corn grain increased with the increase of selenium fertilizer concentration at different stages of selenium spraying. Foliar spraying of selenium fertilizer at the large bell stage and tassel stage could significantly(P<0.05)or extremely(P<0.01)increase selenium content in sweet corn grain. Spraying selenium fertilizer with different concentrations at different stages could improve the sugar degree of sweet corn grain,and the sweetening effects of spraying 0.80-1.00g/L selenium fertilizer at the jointing stage and the large bell stage were great. The cadmium and arsenic contents of grains treated by different selenium concentrations were higher than or equal to CK treatment at the jointing stage and the large bell stage. But cadmium content at the tassel stage was lower than that of CK. With the increase of selenium fertilizer concentration, the fresh ear yield at jointing stage decreased gradually. The fresh ear yield at the large bell stage and the tassel stage increased first and then decreased. Among them,0.80-1.00 g/L foliar spraying of selenium fertilizer at large bellstage had the best yield-increasing effect,while high concentration(2.00 g/L)selenium fertilizer could cause foliar burns and reduce the yield.【Conclusion】Foliar spraying of selenium fertilizer with appropriate concentration at appropriate growth stage can not only increase selenium content in sweet corn kernel and improve the taste of sweetness,but also increase fresh ear yield of sweet corn. Among them,foliar spraying of 0.80-1.00 g/L selenium fertilizer Xinxibao at the large bell stage of sweet corn has the best effect. Whether selenium fertilizer affects heavy metal contents in sweet corn is related to the spraying time of selenium fertilizer.