| Tomato(Lycopersicon esculentum Mill.),as the solanaceae tomato annual vegetable crop,is one of the widespread favorite solanaceous fruit vegetable.Also,the tomato has the largest planting area and consumption in the world.With the rapid development of industry and agriculture,the heavy metal pollution,coming from fertilizer that contains cadmium,copper,organic fertilizer,cupric fungicide,and sewage irrigation,becomes more and more serious,resuotling in a potential threat to the human health.Fulvic Acid(FA)is a polymer organic compound with small molecular weight of phytic Acid.It contains many active functional groups and is easily absorbed by plants and,thus,it has strong biological activity.The structure contains a large number of carboxyl groups,phenolic hydroxyl groups,alcohol hydroxyl groups,and carbonyl groups.These active groups can make the fulvic acid be formed a strong complexation and easily absorbed by the heavy metal.In this experiment,the effects of FA on the growth of tomato and soil properties were studied using the method of nutrient solution and soil potting.The results are described as follows:(1)The leaf spraying FA can significantly relieve the stress caused by Cu and Cd stress on the growth of tomato seedlings,and significantly increase the growth indicators of tomato seedling height,stem and chlorophyll.(2)Spraying on the leaf FA can significantly relieve the Cu,Cd stress on tomato seedlings,the influence of mineral elements content of the P content of stem of easing is most significantly,the processing of spraying FA Cu stress P content was significantly increased by 32.50% than that of Cu stress,FA for Cu,tomato seedlings under Cd stress stem has significant effects of Fe and Mn content,the ease of the maximum 59.36%.(3)The effects of Cu and Cd stress on Cu,Cd content and accumulation in tomato seedlings were significantly alleviated by spraying FA.Spraying FA can reduce the root,stem and leaves of Cu in single stress by 6.49%,26.26% and 17.08 % respectively.When the Cd is under single stress,the root,stem and leaf are increased by 21.06 %,30.00 % and 38.10% respectively.(4)Spraying on the leaf FA can significantly improve the single Cu,Cd and tomato plants under complex stress Pn(18.96%,11.22%,25.01%),Gs(27.16%,34.96%,56.29%),the Tr(55.59%,56.56%,1.23 times),and reduce the Ci(10.07%,8.38%,6.84%).(5)Spraying on the leaf FA can significantly improve the Cu,Cd stress under soil invertase,catalase,acid/alkaline phosphatase activity,including Cu + Cd spraying FA can make under complex stress under soil invertase activity than stress increases by 39.55%.Cu,Cd stress can make the soil Chloroflexi,Bacteroidetes and Planctomycetes richness is reduced,and spraying FA can by increasing the Bacteroidetes,Actinobacteria richness to increase nutrient element content in the soil.Spraying FA can significantly reduce the forms of Cu and Cd that are easy to be used by plants,and increase the forms of Cu and Cd that are difficult to be used.(6)Spraying on the leaf FA can significantly improve tomato under Cu,Cd stress quality and increase production,especially of Vc and total sugar content,including Cu,Cd under single and compound stress under spraying FA can make Vc content than stress increased by 45.92%,26.91% and 11.40% respectively,the total sugar content increased by 20.63%,48.47% and 20.63% respectively. |
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