Study On Zinc And Iron Absorption And Utilization Characteristics Of Different Zinc And Iron Rich Rice Varieties

In this study,the zinc and iron rich red rice variety"Zhuang Hong Gong Mi"and the common red rice variety"Wan Dao 129"were used as experimental materials.Two application levels of zinc fertilizer and two application levels of iron fertilizer were set respectively,and four groups combined application levels of zinc and iron fertilizer were used for pot planting.The zinc and iron contents of the leaves and nutrient organs of the two rice varieties were measured at different stages of fertility.Then,q RT-PCR was used to identify the expression changes of the zinc and iron transporter gene that had been characterized to affect the absorption,transport and distribution of zinc and iron.and to investigate the yield and quality of the two varieties were measured at maturity.The main results were as follows:1.The application of zinc fertilizer promoted the increase of zinc content in the vegetative organs of the two rice varieties.The zinc content in leaves accumulated continuously with the growth stage,and increased to the highest at filling stage.Under different zinc supply levels,Os ZIP5 and Os IRT1 expression levels in positively regulated zinc absorption roots were up-regulated while Os ZIP1 expression levels in negatively regulated zinc absorption roots were down-regulated.The expression levels of Os ZIP8,Os HMA2 and Os ZIP4,which negatively regulated zinc transport to stem,were down-regulated.Os VIT1 and Os VIT2,which positively regulated zinc distribution to leaves,and Os ZIP8,which negatively regulated zinc distribution to leaves,were down-regulated.Os ZIP8,Os VIT1 and Os VIT2,which negatively regulated zinc distribution to grain,showed down-regulated expression trend.The application of zinc fertilizer increased the seed setting rate and thousand seed weight of the two varieties.The higher zinc supply level decreased the amylose content and alkali elimination number of the two varieties.2.The application of iron fertilizer also promoted the increase of iron content in thevegetative organs of the two rice varieties,and the absorption and utilization capacity of the vegetative organs of Zhuang Hong Gong Mi was stronger than that of Wan Dao 129.The Fe content in leaves accumulated continuously with the growth stage and reached the maximum at grout stage.Under different iron supply levels,the expressions of Os IRT1 and Os IRT2 in positively regulated root iron absorption showed an up-regulated trend.Os YSL2,Osspr1 and Os HRZ2,which negatively regulated iron transport to stem,were down-regulated.Os YSL2and Osspr1 which negatively regulated iron distribution to leaves and Os VIT1 which positively regulated iron distribution to leaves showed a downward trend.Os HRZ2 and Os VIT1 of negatively regulated iron distribution to grain and Os YSL2 of positively regulated iron distribution to grain showed a downward trend.The application of iron fertilizer increased the total number of grains per ear and setting percentage of the two varieties,but the amylose and alkali elimination number of the two varieties had no significant effect.3.The application of zinc fertilizer promoted the increase of iron content in the vegetativeorgans of the two varieties.The accumulation law of iron content in rice leaves with different zinc supply levels was consistent with that of zinc during growth period.The expression trend of genes responsible for iron absorption,transport and distribution in different parts of the two varieties was the same as that of genes responsible for zinc absorption,transport and distribution in different parts of the two varieties.The application of iron fertilizer was proportional to the content of zinc in root,glume and grain of the two varieties.The application of iron fertilizer also promoted the accumulation of zinc content in rice leaves,which reached the maximum at filling stage.The expression trend of genes responsible for zinc absorption,transport and distribution in different parts of the two varieties was the same as that of genes responsible for iron absorption,transport and distribution in different parts of the two varieties.The combined application of zinc and iron fertilizer promoted the improvement of the contents of zinc and iron in each vegetative organ of the two varieties,and the contents of zinc and iron in each part increased the most in the ratio of 50 mg Fe SO₄·7H₂O and 120 mg Zinc SO₄·7H₂O.Similarly,the content of zinc and iron in the leaves of the two varieties increased to the highest at the filling stage.Under the combined application of zinc and iron fertilizer,the expression of Os ZIP1 was down-regulated,while the expression of Os IRT1,Os IRT2 and Os ZIP5 was up-regulated.Os ZIP8,Os HMA2,Os ZIP4,Os YSL2,Osspr1,Os HRZ2 in the stem and Os YSL2,Osspr1,Os VIT1,Os VIT2,Os ZIP8 in the leaves and Os ZIP8,Os VIT1,Os VIT2,Os YSL2,Os HRZ2 in the grains The expression level of 2 showed a downward trend.Combined application of zinc and iron fertilizer increased the total number of grains per ear and setting percentage of the two varieties,but had no significant difference in glue consistency between the two varieties.Compared with the application of zinc and iron fertilizer alone,the combined application of zinc and iron fertilizer increased the content of zinc and iron in each vegetative organ,as well as the yield and quality of the two varieties.