Effects of Allelic Variation Controlling Color Trait on Cadmium Tolerance of Brassica juncea L.

Feng Huimin; Xiao Yuanye; Yuan Xiao; Feng Jingqi; Li Haibo; Zeng Honghao; Zhu Yunna; Wang Bin

doi:10.14083/j.issn.1001-4942.2025.09.014

Abstract：Cadmium(Cd)is a kind of non-essential and harmful heavy metal element for the plant,and its accumulation in vegetables significantly impacts food safety.To determine whether the allelic variation con-trolling color trait affect the Cd tolerance of leaf mustard(Brassica juncea L.),the near-isogenic lines of pur-ple leaf 20Z5 and green leaf 20Z6 as experimental materials to study the effects of Cd stress on growth physio-logical characteristics and leaf color of the two mustard varieties.In addition,the Cd accumulation characteris-tics and tolerance of the two varieties were also compared.The results showed that Cd stress significantly re-duced the indicators such as plant height,fresh weight,dry weight and root length in both of the two mustard varieties,but the biomass decline of purple leaf mustard was notably smaller than that of green leaf variety,in-dicating that purple leaf mustard had stronger Cd tolerance.Under Cd stress,there were no significant differ-ences in Cd content,hydrogen peroxide(H2O2)level,relative electrical conductivity,and activities of super-oxide dismutase(SOD),peroxidase(POD)and catalase(CAT)between the two varieties.However,the rel-ative water content and soluble sugar content in leaves of the purple leaf variety were significantly higher com-pared to the green leaf variety,while the malondialdehyde content was significantly lower.It suggested that there was no significant differentce in Cd enrichment capacity between the two varieties,and the stronger os-motic regulation capacity of purple leaf variety might be closely related to its Cd tolerance.Furthermore,the purple leaf variety contained higher level of anthocyanin,indicating that anthocyanin played a crucial role in enhancing the Cd tolerance in purple leaf mustard.The membership function method was used to comprehen-sively evaluate the Cd tolerance of 20Z5 and 20Z6,and the results showed that the mean value of membership function was 0.50 which was 0.46 in green leaf mustard,suggesting stronger Cd tolerance of the purple leaf va-riety than that of the green leaf variety.In summary,purple leaf mustard exhibited stronger Cd tolerance than green leaf variety,suggesting that allelic variation controlling anthocyanin synthesis influence Cd tolerance in leaf mustard.