| Selenium is an essential nutrient for humans and animals,and the per capita intake of selenium in China is far below the recommended intake of selenium by the Chinese Nutrition Society.Selenium deficiency in humans can easily lead to diseases such as Keshan disease,Kashin-Beck disease and other disease,people in selenium-deficient areas often use cereals and their products as the main food source,and wheat has a higher ability to collect selenium than other cereal crops,so it is important to fortify wheat with selenium to improve human health.Lutein is known to protect vision,fight cancer,antioxidant and improve cognitive ability of the brain,but the body cannot synthesize it by itself and needs food supplements.“shannong48”is a high lutein wheat variety approved by Shandong Province in 2021.Selenium fortification of“shannong48”allows people to supplement lutein and selenium at the same time through dietary routes.In this experiment,different amounts of sodium selenite(0,15,30,60 and 120g/hm~2)were sprayed on the foliar surface of wheat at the filling stage to analyze the effect of selenium fertilizer treatment on the selenium content and quality of wheat,in order to screen out the best safe amount of selenium application.At the same time,120 g/hm~2 of selenium fertilizer was sprayed on the foliar surface of wheat for two consecutive years during the filling period,and blanks was used as the control to study the quality formation pattern of“shannong48”during the filling to maturity period and the effect of selenium spraying.The main findings of the experiment are as follows:(1)Foliar spraying of selenium fertilizer significantly increased the selenium content of“shannong 48”seeds.Compared to control treatment,different selenium fertilizer application treatments increased seed selenium content by 0.88～11.38 times.The maximum value of wheat selenium enrichment set limits,should be in accordance with the national health standards(GB 13105-91)in grain selenium content<0.300 mg/kg to implement the standard.In this study,the selenium content of seeds at 30 and 60 g/hm~2 was 0.283 and 0.522 mg/kg,and the selenium content of seeds treated with 30 g/hm~2 was close to the upper limit of this standard,so the recommended selenium application rate of“shannong 48”should not exceed 30g/hm~2.Foliar spraying of selenium fertilizer also significantly increased the selenium content of stems,leaves and spike+glume parts of“shannong48”.Compared to control treatment,selenium fertilizer treatment increased the selenium content of stems by 0.81～7.87 times;leaves by 2.34～15.15 times;and spike+glume by 0.62～9.04 times.(2)Different spraying amounts of foliar selenium fertilizer had different effects on“shannong48”quality indexes.Different selenium spray amounts had no significant effects on grain type,color,moisture,gluten,starch,protein content and elements K,Mn,Fe and Cu content of wheat grain.Spraying selenium fertilizer significantly increased the polyphenol and total flavonoid content of wheat grain,The content of polyphenols under 15,60,120 g/hm~2selenium fertilizer treatment reached 1.13,1.16,1.11 mg/g,which was 26.23%,30.07%,24.44%higher than that of control treatment,respectively.The contents of total flavonoids under15,30,60,120 g/hm~2 selenium fertilizer treatments were 1.15,1.23,1.21,1.12 mg/g,respectively,which were 11.26%,19.21%,17.52%and 8.55%higher than control treatment,respectively.Selenium application could significantly increase the phytic acid content in wheat grain,and the phytic acid content of each selenium fertilizer spray rate(15,30,60,g/hm~2)was 17.78,16.70 and 17.57 mg/g,respectively,which increased by 18.63%,11.44%and 17.24%compared to control treatment,and the high concentration of selenium fertilizer(120 g/hm~2)reduced the phytic acid content and decreased by 4.68%compared with control treatment.(3)In two years of field trials,after foliar spraying of selenium fertilizer(120 g/hm~2)during the filling stage,the selenium content of kernels and spike+glume increased first and then decreased during the period of wheat filling to maturity.The selenium content of stems and leaves showed an overall downward trend.Compared with the initial stage of filling(7th day after flowering),the selenium content of wheat grain increased by 0.79～1.10 times during the ripening stage(35th day after flowering).The selenium content of spike+glume increased by 0.50～0.91 times;The selenium content of stems decreased by 49～50%;The selenium content of leaves decreased by 29～32%.(4)The formation of the main quality index of the seeds of“shannong48”during the grain filling period showed obvious regularity,and the overall effect of spraying selenium fertilizer treatment on the quality formation pattern during the filling period was not significant.The protein content of grains treated with control treatment and 120 g/hm~2 selenium fertilizer showed a“V”shape change throughout the filling period,and in general,the lowest value of the protein content of each treated grain appeared around the 21st day after flowering.The starch content and flavonoid content of grain showed a gradual increase trend throughout the filling period.The content of grain polyphenols showed a trend of first down and then increasing during the whole filling period,and the content of each treatment was lowest on the28th day after flowering.The content of phytic acid in grains treated with 120 g/hm~2 selenium fertilizer increased first and then decreased throughout the filling period,and the content was highest on the 21st day after flowering,reaching 16.57～17.50 mg/g.The phytic acid content of control treated grains varied in waves throughout the filling period,and the content was highest on the 21st day after flowering,reaching 16.92～17.15 mg/g.On the whole,selenium fertilizer treatment had little effect on the accumulation of protein,starch,flavonoids,polyphenols and phytic acid in the grain filling stage,but the content of selenium fertilizer treated grain phytic acid was significantly lower than that of control treatment in the early stage of grouting,and the total flavonoid content was significantly higher than that of control treatment,and the later law was basically the same.(5)The spraying of selenium fertilizer significantly reduced the seed lutein content of“shannong 48”,with 7.34%,13.93%,16.20%and 9.04%lower than that of control treatment in different selenium fertilizer treatments(15,30,60 and 120 g/hm~2),respectively.The seed lutein content showed an overall trend of increasing and then decreasing during the period from grain filling to maturity,with the highest content on the 14th day after flowering.In both trials,the seed lutein content of 120 g/hm~2 selenium fertilizer treatment was significantly higher than that of control treatment at 7～14 days after flowering. |
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