Effects Of Intercropping With Reciprocal Post-grafting Generation Of Two Ecotypes Of G.Parviflora On Cadmium Accumulation Of L.Sativa

Lactuca sativa which is an annual or biennial crops commonly known as lettuce with leafa,and is a family of lettuce.And it is a common representative of leafy vegetables in Sichuan area.Studies have confirmed that L.sativa growth in the heavy metal pollution on soil has accumulated the amount of Cd,which directly affected the quality and yield of L.sativa.Aiming to remedy the problem of soil Cd contamination in vegetable area,via two ecotypes of Galinsoga parviflora Cd hyperaccumulator(G.parviflora of farmland ecotype and G.parviflora of mine ecotype)for reciprocal grafting,get post-grafting generation of G.parviflora of mine ecotype as rootstock(MR),post-grafting generation of G.parviflora of mine ecotype as scion(MS),post-grafting generation of G.parviflora of farmland ecotype as rootstock(FR)and post-grafting generation of G.parviflora of farmland ecotype as scion(FS),and then generation of ungrafted could be used as control(FCK and MCK),to study Cd accumulation characteristics of reciprocal post-grafting generationof two ecotypes of G.parviflora,and intercropping reciprocal post-grafting generation of G.parviflora with L.sativa,to study the effects of intercropping on ecophysiological characteristic and Cd accumulation characteristics of two kinds of plants.The study was in order to screen out reciprocal post-grafting generation of G.parviflora which could significantly reduce the Cd content L.sativa and make L.sativa be stable or high-yield.This study would be important scientific significance and value on Cd contaminated L.sativa-prodncing areas and other vegetables.The main results were as follows:1.The root biomass,leaf biomass,shoot biomass and root/shoot ratios of MS were higher than MCK under Cd stress.The stem biomass,leaf biomass and shoot biomass of FCK were higher than others.Antioxidant enzyme(SOD,POD and CAT)activities of MS were significantly higher than others.The Cd contents of root,stem,leaf and shoot of MS were significantly higher than others.Compared with G.parviflora of MCK,the Cd content of leaf and shoot of MS were increased by 2.18%and 7.96%.The Cd content of stem,leaf and shoot of FS were significantly higher than FCK.As far as Cd accumulation amount,the Cd accumulation amount of root and the whole plant of MS were significantly higher than others;the Cd accumulation amount of root,stem,leaf shoot and the whole plant of MS were increased by 119.48%,4.90%,13.81%,9.24%and 28.27%than MCK.2.Respectively intercropping G.parviflora of farmland ecotype,G.parviflora of mine ecotype and reciprocal post-grafting generation of two ecotypes of G.parviflora with L.sativa under Cd stress.The results show compared with monoculture,the biomass,antioxidant enzyme(SOD,POD and CAT)activities and photosynthetic pigment contents of L.sativa intercropping with MS were increased,the above shows that the physical growth and resistance of L.sativa intercropping with MS were all showed the intercropping advantage.As far as Cd absorption concerned,the Cd content of roots of L.sativa intercropping with FR and G.parviflora of farmland ecotype were significantly higher than monoculture,but the Cd content of shoots of L.sativa intercropping with FR and G.parviflora of farmland ecotype were lower.The Cd content of roots and shoots of L.sativa intercropping with MS,G.parviflora of mine ecotype and MR were lower than monoculture.The Cd content of shoots of L.sativa intercropping with MS was the lowset,and was reduced by 29.16%.Soil pH,soil available Cd concentration,soil nutrition availability and soil enzyme activities of L.sativa intercropping with MS were higher than monoculture,and L.sativa intercropping with MS improved the soil environment.3.After intercropping with L.sativa,as far as the shoot of G.parviflora,the biomass,the Cd content and the Cd accumulation amount of MS intercropping with L.sativa were significantly higher than G.parviflora of mine ecotype intercropping with L.sativa,the biomass and the Cd accumulation amount of FS intercropping with L.sativa were significantly higher than G.parviflora of farmland ecotype intercropping with L.sativa.Interms of the root of G.parviflora,the biomass and the Cd accumulation amount of MS intercropping with L.sativa were significantly higher than G.parviflora of mine ecotype intercropping with L.sativa.The Cd content and the Cd accumulation amount of FS intercropping with L.sativa were significantly higher than G.parviflora of farmland ecotype intercropping with L.sativa.The biomass,the Cd content and the Cd accumulation amount of FR intercropping with L.sativa were significantly higher than G.parviflora of farmland ecotype intercropping with L.sativa.4.In conclusion,the Cd contents of root,stem,leaf and shoot of MS were significantly higher than others,besides the Cd content of stem,leaf and shoot of FS were significantly higher than FCK which indicated that grafting can improve the ability of cadmium repair in G.parviflora generation and the effect of scion on cadmium content was higher than that of rootstock.The intercropping patterns of intercropping MS with L.sativa most likely to achieve the remediation of soil Cd pollution goal while reduce the Cd accumulation amount and increase the biomass of L.sativa.