Effects Of Graphene And Oxides On Larix Olgensis Seedling Growth And Properties Of Dark Brown Forest Soils

Graphene and oxides are widely used because of their special properties.They have potential risks to the ecological environment while improving our living standards.But at present,there is no report on the effects of graphene and oxides on forest tree species.This paper systematically studied the growth of Larix olgensis A.Henry seedlings and the changes of soil physicochemical properties and soil enzyme activities in Dark Brown Forest Soils under different time and concentration of graphene and graphene oxide stress,so as to provide theoretical basis for evaluating the ecological environmental effects of graphene and oxide on Dark Brown Forest Soils in northeastern China.The main results are as follows:1.Graphene treatment affected many physiological and biochemical characteristics and growth of Larix olgensis seedlings,and varied with its concentration and treatment time.With the increase of graphene concentration,relative conductivity and malondialdehyde(MDA)contents,POD and SOD activities,soluble protein and proline contents,chlorophyll contents,superoxide anion and hydrogen peroxide contents,root length,surface area,volume and average diameter of seedlings all changed significantly.The results showed that the antioxidant system of larch seedling leaves was damaged after graphene treatment.The short-term toxicity of graphene to seedlings was mainly caused by oxidative stress of roots and slow development of roots.After long-term treatment,the antioxidant system of seedlings was severely damaged.2.Graphene had a significant effect on the cycling of nitrogen and phosphorus in Dark Brown Forest Soils.Low concentrationes of graphene promoted hydrolytic nitrogen contents and urease activities,while high concentrationes inhibited them.After high concentrationes graphene treatment,catalase activities increased significantly in Dark Brown Forest Soils,acid phosphatase activities decreased,and the effect of dehydrogenase activities in Dark Brown Forest Soils was relatively small,indicating that soil microorganisms in Dark Brown Forest Soils were under stress state and produced ROS.Graphene affects nutrient uptake of Larix olgensis seedlings by affecting soil nutrient changes in Dark Brown Forest Soils,resulting in different root morphology and chlorosis of leaves due to lack of certain nutrients.3.Graphene oxide treatment affected many physiological and biochemical characteristics and growth of Larix olgensis seedlings,and varied with its concentration and treatment time.With the increase of graphene oxide concentration,the biomass,POD and SOD activities,soluble protein and proline contents,chlorophyll contents,superoxide anion and hydrogen peroxide contents,relative conductivity and MDA contents,root length and surface area of seedlings all changed significantly.It may be that graphene oxide has a significant effect on Larix olgensis seedlings,resulting in the production of reactive oxygen species in the seedlings and different oxidative stress reactions.All in all,the inhibitory effect was significant at 30 days,and some concentrations had significant promotion effect at 40 days and 50 days.4.The change of organic matter contents was consistent with that of hydrolyzed nitrogen contents under graphene oxide treatment,but contrary to that of available phosphorus contents.Graphene oxide had a significant effect on nitrogen cycle in Dark Brown Forest Soils.High concentrationes of graphene oxide promoted hydrolytic nitrogen contents and urease activities in Dark Brown Forest Soils after enrichment of graphene oxide in a short time or at a low concentrationes for a certain time.The trend of catalase activities and dehydrogenase activities in Dark Brown Forest Soilswas consistent.5.The effects of graphene and graphene oxide on Larix olgensis seedlings and soil environmental changes of Dark Brown Forest Soils have similarities and differences.For Larix olgensis seedlings,the trend was similar at 30 days,but opposite at 40 days and 50 days.Effects on the properties of Dark Brown Forest Soils,the trend was opposite at 30 days,and similar at 40 days and 50 days.