Effect Of Low Iron Stress On Physiological And Biochemical Indexes Of Soybean Seedlings

In this study four iron efficient soybean varieties(changnongl5,changnong20,jiyu 75,jiyu99)and four iron inefficient soybean varieties(jinong27,jiyu87,jiyu92,jiyu93)were used as material,the 2018-2020,using pot method,the stress of low iron(calcareous soil)and contrast(calcareous soil+topdressing iron fertilizer)under the condition of two kinds of PROcessing,The photosynthetic characteristics,antioxidant enzyme activity,iron content,dry matter accumulation,osmotic regulatory substance and gene expression of soybean varieties with different iron efficiency at seedling stage(V1,V2,V3 and V4)were studied comprehensively and systematically.This study will play a positive role in further understanding the mechanism of iron deficiency and breeding new varieties of iron efficient soybean.The specific research results are as follows:1.Under the stress of low iron,the iron content in the leaves of the varieties with high efficiency was significantly higher than that of the varieties with low efficiency at the seedling stage(V1,V2,V3 and V4).Under the stress of low iron,the iron content in the root system of the varieties with high iron efficiency was significantly higher than that of the varieties with low iron efficiency at the seedling stage(V1,V2,V3 and V4).Under the stress of low iron,the Fe3+ reductase activity of the roots of the fe-efficient cultivars was significantly higher than that of the fe-inefficient cultivars at the V2,V3 and V4 stages.2.Under the stress of low iron,the net photosynthetic rate of leaves of iron efficient cultivars was significantly higher than that of iron inefficient cultivars in V3 and V4.Under the stress of low iron content,the chlorophyll content of fe-efficient cultivars was higher than that of fe-inefficient cultivars at the seedling stage(V1,V2,V3 and V4),reaching a significant level.Under the stress of low iron content,ALA content of fe-efficient cultivars was significantly higher than that of fe-inefficient cultivars in V2,V3 and V4.3.Under the stress of low iron,SOD activity in the roots of fe-efficient varieties was significantly higher than that of fe-inefficient soybean varieties at V2,V3 and V4.Under the stress of low iron,the POD activity in the root system of the varieties with high iron efficiency was higher than that of the varieties with low iron efficiency at V2 and V3,and the difference reached a significant level.Under the stress of low iron,CAT activity in the root system of the varieties with high iron efficiency was higher than that of the varieties with low iron efficiency at the seedling stage(V1,V2,V3 and V4),with a significant difference.Under the stress of low iron,the malondialdehyde(MDA)content in the root system of the varieties with low iron efficiency was significantly higher than that of the varieties with high iron efficiency at V2,V3 and V4.Under the stress of low iron,the low-efficiency varieties in The V2,V3 and V4 stages had higher H2O2 content in their roots than that of the high-efficiency varieties,reaching a significant level.Under the stress of low iron,in the seedling stage(V1,V2,V3 and V4),the content of O2-in the root system of the varieties with low iron efficiency was higher than that of the varieties with high iron efficiency,reaching a significant level.4.Under the stress of low iron,the soluble sugar content in roots of low-iron cultivars was significantly higher than that of low-iron cultivars at the seedling stage(VI,V2,V3 and V4).Under the stress of low iron,the soluble PROtein content in roots of fe-efficient varieties was significantly higher than that of fe-inefficient soybean varieties at V2,V3 and V4.Under the stress of low iron,the PROline content in the root system of the varieties with high iron efficiency was significantly higher than that of the varieties with low iron efficiency at the V2,V3 and V4 stages.5.Under the stress of low iron,the citric acid content in the leaves of fe-efficient varieties was higher than that of fe-inefficient soybean varieties at V2,V3 and V4,reaching a significant level.Under the stress of low iron,the citric acid content in the root system of the varieties with high iron efficiency was significantly higher than that of the varieties with low iron efficiency at V2,V3 and V4.Under the stress of low iron,malic acid content in leaves of fe-efficient cultivars was higher than that of fe-inefficient soybean cultivars at V2,V3 and V4,reaching a significant level.Under the stress of low iron,the malic acid content in the root system of the varieties with high iron efficiency was significantly higher than that of the varieties with low iron efficiency at the V2,V3 and V4 stages.6.At the seedling stage(V4),under the stress of low iron content,the main root length,lateral root number and plant height of the varieties with high iron content were all higher than those with low iron content,with significant differences.The dry weight of iron low efficiency cultivars was higher than that of iron high efficiency cultivars,but the difference was not significant.7.Under the stress of low iron content,the expression level of FR02 in varieties with high iron efficiency was higher than that of varieties with low iron efficiency at the seedling stage(V1,V2,V3 and V4).Under the stress of low iron,IRT1 expression was higher in the seedling stage(V1,V2,V3 and V4)than in the low-iron strain.However,IRT1 expression of soybean varieties with different iron efficiency was higher than that of control in V2,V3 and V4.8,under the stress of low iron,V1-V4 period,different iron efficiency of soybean varieties of correlation degree analysis,the indicators of the final result is:the blade iron content>Fer3+ reductase activity>root iron conteLt>leaf net photosynthetic rate,content of PROline content>CAT enzyme activity>ALA>SOD activity of chlorophyll content,POD activity content of soluble PROtein,soluble sugar conten>H2O2 content>O2-content MDA content.