Effects Of Intercropping Accumulator Plants On Growth And Cadmium Accumulation Of Grape Seedlings

The grape is one of the important fruit trees all over the world,which is beautiful in appearance and has various forms of product.Grape planting has become the momentous pillar industry of the incomes for farmers.However,the growing problem of soil heavy metal contamination in orchard has been threatening to growth and production safety of fruit trees like grape.Based on this,five cadmium(Cd)hyperaccumulators were used to intercrop with grape seedlings firstly by a pot experiment in this study to screen out the hyperaccumulator Bidens pilosa which could reduce the Cd content most and be best for growth of grape seedlings.In addition,four Bidens L.species were further used to intercrop with grape seedlings to select out the species of Bidens L.that could significantly decrease the Cd content of grape seedlings and available Cd content in soil and be beneficial to growth of grape seedlings,which could provide some reference for the production safety of grape and remediation of the Cd-contaminated soil of vineyard.The main results were as follows:1.The results of the experiment of the effects on intercropping five hyperaccumulators including Galinsoga parviflora,Siegesbeckia orientalis,Solanum nigrum,Bidens pilosa and Crassocephalum crepidioides on growth and Cd accumulation of grape seedlings showed that:(1)Compared to monoculture,intercropping with hyperaccumulators except S.nigrum decreased the biomass,chlorophyll content and soluble protein content of grape seedlings,but intercropping with five hyperaccumulators increased the soluble sugar content and partially increased the antioxidant enzyme(SOD,CAT)activity.(2)Intercropping with five hyperaccumulators reduced the Cd contents in root and shoot of grape seedlings compared to monoculture.(3)The treatment of intercropping with B.pilosa most significantily reduced the Cd content of grape seedlings and made the biomass comparatively decreased least.And the Cd content and biomass in shoot of grape seedlings decreased respectively by 86.84% and 3.68% compared with their own monoculture.Therefore,B.pilosa is the most favorable material of the five hyperaccumulators for growth and Cd content decrease of grape seedlings.2.The results of the experiment of the effects on intercropping four Bidens L.species including Bidens bipinnata,Bidens pilosa,Bidens parviflora and Bidens biternata on growth and Cd accumulation of grape seedlings showed that:(1)Compared to monoculture,intercropping with four Bidens L.species decreased the biomass,photosynthetic parameters,photosynthetic pigment content,total nitrogen and total potassium content and reduced the Cd contents in root and shoot of grape seedlings,but increased the soluble sugar content,SOD activity and partially increased the total phosphorus content and CAT activity.(2)Compared to monoculture,grape seedlings intercropping with four Bidens L.species increased the urease activity,organic and alkali soluble nitrogen content,increased the catalase activity of soil except intercropping with B.bipinnata,but decreased the phosphatase and sucrase activity,available phosphorus and available potassium content and pH of soil.(3)Each treatment had different effects on five fractions of Cd content in soil.Grape seedlings intercropping with B.pilosa decreased most the exchangeable,carbonate and Fe-Mn oxide bound of Cd content and increased most the residue of Cd content in soil.(4)The treatment of intercropping with B.pilosa most significantily reduced the Cd content and made the biomass comparatively decreased least of grape seedlings,and effectively reduce the bioavailability of Cd in soil,which can reduce the damage to the plant.And the Cd content and biomass in shoot of grape seedlings decreased respectively by 92.21% and 9.35%,the exchangeable,carbonate,Fe-Mn oxide bound and organic matter bound of Cd content in soil decreased respectively by 9.38%,12.64%,11.36% and 2.76% and the residue of Cd content in soil increased by 91.67% compared with their own monoculture.In comprehensive comparion,B.pilosa is most beneficial for growth of grape seedlings and remediating the Cd-contaminated soil of vineyard.3.Two experiments of grape seedlings intercropping with five hyperaccumulators and four Bidens L.species showed that: B.pilosa is the best material for growth and Cd content decrease of grape seedlings,which can be reasonably applied to the production safety of grape and remediation of the Cd-contaminated soil of vineyard.