Pb Resistance And Genetic Effects Of Pb Accumulation In Maize Inbred Lines

The objective of this study was to investigate the variations for SOD, POD, CAT, MDA, Chl of 10 maize inbred lines and synergy between these antioxidant enzymes. In addition,12 maize inbred lines were crossed using Griffing's Method 4 and parents and their 66 hybrids were grown in low, medium and high Pb polluted soil.The content of stem-leaves and grains was determined, and the effects of the genotype (G), environment (E), and G×E on Pb content were investigated in combined variance analysis, simultaneously, the GCA, SCA and heterosis effect on Pb content were studied. The bioremediation capacities of 66 hybrids were preliminary evaluated between different pollution levels of Pb using the total accumulation coefficient as evaluation index. The results indicated that:1.Superoxide dismutases (SOD) was the dominant physiological factors which alleviated oxidative stress and lipid peroxidation under Pb stess;There were synergistic effect between superoxide dismutases and peroxidase;More than half of maize inbred lines have not got hurt in physiological level.2.By analyzing physiological indicators of leaves and dry weight of aboveground parts, the result indicated that maize inbred lines had strong resistance for Pb stress.3.There were greater genetic variations for Pb content of stem-leaves and grain. The difference of Pb content of stem-leaves and grain among 3 Pb levels reached 0.01 probability level, and the same was among genotypes.The interaction between location and genotype also showed significant difference (P<0.01);it indicated that this trait was affected jointly by the genotype (G) and environment (E). The two trait showed high generalized heritability, and was mainly based on non-additive gene effects. 4.Analysis showed that the GCA variance and SCA variance of Pb content in stem-leaves were very notable (P<0.01)under different pollution conditions of Pb.In high Pb polluted soil, there was an extremely significant difference between the GCA variance and SCA variance of Pb content in grains. Zheng58 had so higher positive GCA effect slightly affected by environments that it was suitable for combining hybrids which had high concentration of Pb in stem-leaves and very low concentration of Pb in grains in low or medium Pb polluted soil. R08,ES40 and S37 had so higher negative GCA effect slightly affected by environments that it was suitable for combining hybrids which had very low concentration of Pb in stem-leaves and grains in low Pb polluted soil.5.There were positive and negative heterosises for Pb content of stem-leaves, but mainly showed positive. The sizes of heterosis were diverse in different hybrids.The combination from inbred lines of high Pb and low Pb was more likely to produce extreme hybrids.An extremely positive relation would be presented between Pb content in stem-leaves and grains of hybrids and average GCA effect of parents.6.The stem-leaf of maize had strong accumulation to Pb in soil, resulting in maize possessing potential bioremediation ability. Simultaneously, the stem-leaf of maize would be polluted easily by Pb among low/medium/high Pb levels in soil.It maybe exist a mechanism that can significant reduce Pb translocation efficiency from stem-leaf to grain. The grian of maize would be hardly polluted as Pb content was below 333.32 mg·kg-1 in soil.7.The Breeding for maize germplasms of high or low Pb concentration in stem-leaves should be paid attention to as Pb content was below 50.65 mg·kg-1 in soil. The Breeding for maize germplasms of high concentration of Pb in stem-leaves and very low concentration of Pb in grains should be paid attention to as Pb content was above 50.65 mg·kg-1 in soil.