Resource Allocation And Population Genetic Structure Analysis Of Vicia Faba With Cd Pollution For Different Generations

Once heavy metal contamination in the soil occurs,the latency,chronicity and continuity of its ecological effects are very prominent.It is urgent to analyze the evolutionary ecological toxicological effects of such contaminated plants,but previous studies mainly focused on the short-term and acute toxicity of heavy metal contamination.Few studies have been carried out on the ecological differences,resource allocation characteristics and population genetic structure between different generations of plant populations under the condition of long-term contamination.This study randomly selected five generations(4th,8th?11th,13th and 16th generations)of Vicia faba L.variety C(K0697)continuously cultivated in the environment of cadmium pollution(10 mg/kg,60 mg/kg)and the control group without cadmium pollution in the same generation.The ecological differentiation and genetic structure of Vicia faba L.populations in different generations under Cadmium persistent pollution were analysed from three aspects(resource allocation,quantitative traits and molecular data).The research results are as follows:(1)Cadmium pollution has a complicated impact on the growth and development of Vicia faba L.populations.In general,cadmium pollution can inhibit the growth and development of Viciafaba L.,resulting in inhibition of plant height,leaf length,leaf width,leaf aspect ratio and taproot length,and the higher the concentration,the more obvious the inhibition.The inhibition was also related to generational status and growth stages of Vicia faba L.The inhibition of some traits was not obvious in the middle and late stages of growth and development.With the increase of generations of continuous contamination,the variation of quantitative characters of Vicia faba L.populations fluctuated around the control groups.(2)The effect of cadmium pollution on the biomass allocation of Vicia faba L.populations is also complex.The population biomass increased in the short generation of cadmium pollution,but decreased significantly with the prolongation of the generation of cadmium pollution,and the higher the concentration of cadmium pollution,the more obvious the inhibition.In addition,under the condition of cadmium pollution,the distribution proportion of root biomass,stem and leaf biomass of Vicia faba L.increased,while that of reproductive biomass decreased.Under different cadmium pollution conditions,the trend of biomass allocation among different generations of Vicia faba L.populations is not consistent.Generally,.with the increase of cadmium pollution concentration,the coefficient of variation of biomass allocation among generations of Vicia faba L.populations increases gradually,and the difference of biomass allocation among different generations of Vicia faba L.populations increases.(3)Overall,the genetic diversity of Vicia faba L,populations decreased,the genetic distance between generations increased,the number of effective alleles decreased under the condition of continuous cadmium pollution,and the effect of high concentration of cadmium pollution on population genetic structure was more obvious.However,this change did not change linearly with the increase of Cd-contaminated broad bean population.In some generations,genetic diversity,effective allele number and genetic distance showed a rebound.However,this change did not increase linearly with the increase of Cd-contaminated Vicia faba L.generations.In some generations,genetic diversity,effective allele number and genetic distance showed a rebound.At the same time.the Genetic differentiation of Vicia faba L.populations caused by high concentration of cadmium pollution is more obvious than that caused by low concentration of cadmium pollution.(4)With the prolongation of cadmium pollution,the quantitative characters and resource allocation of Vicia faba L.populations in different generations were fluctuating around the control groups.Under the condition of cadmium pollution,the genetic structure of Vicia faba L.populations in different generations did not change linearly,but showed the rule of diversification.