Effects Of Multi-generation Copper Stress And Arbuscular Mycorrhizal Fungi On The Fitness Of Elsholtzia Splendens Offsprings

Heavy metal contamination of the soil has been a problem and research hotspots in the controlling of the global environmental pollution.Arbuscular mycorrhizal fungi(AMF),a common symbiosis with most plants,has been verified to widely distribute in heavy metal contaminated soils and strongly help plants to adapt to the stress of heavy metal.Elsholtzia splendens,a Cu-tolerance plant,can form symbiosis easily with AMF.In order to explore the effect of multi-generation copper stress and arbuscular mycorrhizal fungi on the fitness of plants,we compared the offspring fitness of Elsholtzia splendens after two-generation acclimation and the growth,morphological,heavy metal accumulation,reproductive traits of E.splendens after three-generation acclimation under four treatments CK(no AMF,no Cu)Cu(no AMF,with Cu),AMF(with AMF,no Cu),Cu and AMF(with AMF,with Cu).The results are shown in the followings.1.The seed surface area,perimeter,length and width of Elsholtzia splendens with two-generation heavy metal copper acclimation were significantly lower than those in the other three treatments.However,compared with the seeds of Elsholtzia splendens with two-generation heavy metal copper acclimation,the seeds of Elsholtzia splendens with two-generation heavy metal copper acclimation and AMF inocluation significantly increased the seed surface area,perimeter,length and width.The thousand-grain weights of Elsholtzia splendens seeds with two-generation heavy metal copper acclimation was similar to those in the other three treatments.No matter what the heavy metal copper stress concentration is,the seed germination traits and seedling growth of Elsholtzia splendens with two-generation heavy metal copper acclimation were significantly lower than Elsholtzia splendens with two-generation heavy metal copper acclimation and AMF inocluation.In saddition,the radicle length of the seedlings of Elsholtzia splendens with two-generation heavy metal copper acclimation and AMF inocluation was significantly higher than those in the other three treayments indicating that after two-generation heavy metal copper acclimation,inoculation AMF could increase the radicle length to enhance the ability of seedling to capture nutrients,thereby enducing the inhibition of heavy copper stress on the growth of Elsholtzia splendens offspring fitness.2.Compared with the control,the acclimation of the three-generation heavy metal copper stress significantly inhibited the plant growth,the plant height,basal diameter,root biomass,stem biomass,leaf biomass,total root length,root surface area,root average diameter,root-tips of the Elsholtzia splendens.Compared with the Elsholtzia splendens with two-generation heavy metal copper acclimation,Elsholtzia splendens with two-generation heavy metal copper acclimation and AMF inoculation significantly increased all of the plant morphology traits,thereby promote the growth of Elsholtzia splendens plant.3.Compared with the control,the acclimation of the three-generation heavy metal copper stress significantly delayed the onset flowering date,peak flowering date and last flowering date,and shortened the flowering duration time,inhibited the length of inflorescence,inflorescence width,reducing the total seed weight of the plant,the total number of seedsof Elsholtzia splendens.Compared with Elsholtzia splendens with two-generation heavy metal copper acclimation,Elsholtzia splendens with two-generation heavy metal copper acclimation and AMF inoculation significantly advanced the all flowering date,increased the inflorescence length,inflorescence width,inflorescence number,total seed weight and total number of seeds.4.Compared with the control,the acclimation of the three-generation heavy metal copper stress significantly increased the heavy metal copper content in different parts of plants,also improved the P,K,and Fe content of roots,P and Fe content of stems of Elsholtzia splendens.However,compared with Elsholtzia splendens with two-generation heavy metal copper acclimation,Elsholtzia splendens with two-generation heavy metal copper acclimation and AMF inoculation significantly decreased the heavy metal copper content in roots,leafs and stems of the plant,decreased the P,S,and K content of roots and P in the stem of Elsholtzia splendens.