Screening Of Low Cadmium Accumulation Oat Cultivars And Physiological Responses Of Different Cultivars To Cadmium Stress

Cd pollution in farmland is increasing day by day,which seriously affects the safe and high-quality production of crops.Screening oat varieties with low Cd accumulation characteristics has important guiding significance for the safe utilization of contaminated farmland.In this study,18 oat cultivars were used as test cultivars to conduct field random block experiments for two consecutive years in moderately and mildly cadmium-contaminated farmland.According to the high Cd accumulation variety‘Yanke.2’(Yh)and the low Cd accumulation variety ‘200919-7-1’(Yl)screened in field experiments,pot experiments were carried out to analyze the effect of different Cd accumulation oat varieties on the oat varieties.Physiological responses to Cd stress.The main results are as follows:1.Yield cluster analysis on Cd accumulation characteristics and yield of different oat varieties showed that the grains of 5 varieties including 201229-1-1,200919-7-1,Bayou 14,Mengyan 3 and Mengyan 1 had the highest yield.Low Cd accumulation and high grain yield characteristics.Among them,the target hazard coefficient(THQ)of 201229-1-1,200919-7-1 and Bayou 14 were all less than 1 in the two-year test;201229-1-1,201229-1-1,5.Four varieties of oat grass,including Bayou 14 and Bayan 6,have the characteristics of low Cd accumulation and high grass yield.2.The Cd content of oat grains has a very significant positive correlation with the Cd enrichment coefficient of the stem and the Cd transport coefficient from root to grain,stem to grain,leaf to grain;in principal component analysis,the Cd enrichment coefficient in stem and The transport coefficients of Cd from root to grain,stem to grain and leaf to grain contributed significantly to distinguishing oat varieties with high and low Cd accumulation.3.Under Cd stress,the plant growth,gas exchange parameters and chlorophyll fluorescence parameters of high Cd accumulation oat cultivar(Yh)and low Cd accumulation oat cultivar(Yl)were inhibited.and Yl decreased by 38.2% and 40.8%,35.0% and 57.1%,14.7% and 27.3%,respectively;Cd stress induced the activities of antioxidant enzymes in leaves of the two types of oat varieties,especially SOD activities were significantly enhanced,Yh and The increase of Yl was 41.9% and 44.9%,respectively;meanwhile,Cd stress significantly increased the MDA content,and the increase of Yh and Yl was 22.2% and 18.1%,respectively.In conclusion,among the 18 oat varieties,201229-1-1 and Bayou 14 have the characteristics of low Cd accumulation in grains and forages at the same time.Correlation analysis and principal component analysis showed that stems were the key organs affecting the differences in Cd content in oat grains.The transport process of Cd from roots to grains,stems to grains,and leaves to grains is the key transport process that causes the difference of Cd content in oat grains.Under Cd stress,compared with low-Cd-accumulating oat cultivars,high-Cd-accumulating oat cultivars have higher biomass and antioxidant enzyme activities,as well as stronger net photosynthetic rate and excellent chlorophyll fluorescence characteristics,thus exhibiting stronger Cd resistance.