Effects Of Pb Stress On Growth,Development And Physio-biochemical Of Brassica Napus L.

With the continuous improvement of people’s quality of life,the demand for oil in China has rapidly increased.However,the arable land area in China is limited and polluted by 19.4%,among which lead(Pb)is the main heavy metal pollutant and one of the key heavy metals for monitoring and prevention.Screening out rapeseed germplasm resources with different Pb tolerance and enrichment abilities,providing theoretical basis and germplasm resources for Pb tolerance breeding and remediation of Pb contaminated soil in Brassica napus L..This study evaluated the Pb tolerance of 60 Brassica napus L.varieties during the germination stage.Four different tolerant rapeseed varieties were selected for the determination of physiological and biochemical indicators at seedling stage,agronomic traits at maturity stage,and Pb content.Rapeseed germplasm resources with different Pb tolerance and enrichment abilities were selected,and the following results were obtained:1.Divide 60 samples of Brassica napus L.into four categories: Pb tolerant,medium Pb tolerant,weak Pb tolerant,and Pb sensitive.The varieties with the strongest Pb resistance are Huayou 9 and Baoyou 10,while ZY511 has the weakest Pb resistance.Germination rate,germination potential,root length,bud length,fresh weight,and dry weight can be important indicators for screening the strength of Pb tolerance in Brassica napus L.during germination.2.As the concentration of Pb stress increases,the activities of SOD,POD,CAT,and the contents of proline,soluble sugar,and soluble protein in the leaves of Brassica napus L.significantly increase,thereby alleviating Pb toxicity.3.As the concentration of Pb stress increases,the agronomic traits of Brassica napus L.,such as plant height,main inflorescence length,effective number of pods in the main inflorescence,effective number of pods in the whole plant,pod length,and yield per plant,all significantly decrease.The weaker the Pb tolerance,the greater the impact on the agronomic traits of Brassica napus L..4.As the concentration of Pb stress increases,the Pb content in different parts of rapeseed is root>stem>leaf>pod>grain.Under the same Pb concentration,the order of Pb enrichment ability of the tested rapeseed is: ZY511>Zhongshuang 9>Yuyou5>Huayou 9.