Five Kinds Of Malvaceae Plant Physiological Response And Cadmium Enrichment Characteristics Under Cd Stress

At present,the research of physiological response of malvaceae and enrichment characteristicsare relatively few under Cd stress.In this study,in order to discover new plant repair materials from malvaceae and reveal the physiological response to cadmium stress and accumulation characteristics of the five plants of malvaceae,Sida rhombifolia L.,Malva rotundifolia L.,Malva crispa L.,Abutilon theophrasti Medicus,Malva sinensis Cav.as experimental material,a pot experiment was conducted to observe and analysis the growth parameters,photosynthetic gas exchange parameters,photosynthetic pigment content,malondialdehyde content(MDA),antioxidant enzyme(SOD,CAT,POD,APX)activity of plants and enrichment characteristics of cadmium in different Concentrations of Cd(0,5,15,30,60,100 mg/kg).The research results show that:1)Five kinds of plants are showed strong tolerance to Cd and plants did not wither or die.Cd suppress the critical concentration of Sida rhombifolia L.,Abutilon theophrasti Medicush and Malva sinensis Cav.'s growth at 100?5?15 mg/kg,but 100 mg/kg of Cd treatment has yet to reach suppress the critical concentration of Malva rotundifolia L.and Malva crispa L..Low concentration of Cd to promote Sida rhombifolia L.'s growth,and high concentration of Cd inhibit its growth,their dry weight of biomass compared not significantly lower under 5-60 mg/kg Cd stress;5-100 mg/kg Cd concentration promote Malva rotundifolia L.'s growth,It's dry weight of biomass is significantly higher than control under 5-100 mg/kg Cd stress;but Abutilon theophrasti Medicush and Malva sinensis Cav.'s growth is restrained under Cd stress,their dry weight of biomass was reduced by 61.09% and 61.09% respectively compared with control under 100 mg/kg Cd stress.The plants tolerance to cadmium:Malva rotundifolia L.>Malva crispa L.>Abutilon theophrasti Medicush>Sida rhombifolia L.>Malva sinensis Cav.;The enrichment Cd ability of plants:Abutilon theophrasti Medicush>Malva crispa L.>Malva rotundifolia L.>Malva sinensis Cav.>Sida rhombifolia L.;The transport Cd ability of plants:Malva rotundifolia L.>Malva crispa L.>Malva sinensis Cav.>Abutilon theophrasti Medicush>Sida rhombifolia L.;Malva rotundifolia L.is a Cd hyperaccumulation plant,Sida rhombifolia L.and Abutilon theophrasti Medicush are Cd enrichment plant,Malva crispa L.and Malva sinensis Cav.are Cd tolerance plant.2)Photosynthesis in Malva sinensis Cav.is mainly affected by stomatal factors,and Photosynthesis in Sida rhombifolia L.?Malva rotundifolia L.?Malva crispa L.and Abutilon theophrasti Medicush is influenced by stomatal factors and non-stomatal factors(leaf area,MDA content,antioxidant enzyme activity,photosynthetic pigment content and Cd content in root,stem and leaf)under Cd stress.Photosynthesis in Sida rhombifolia L.?Abutilon theophrasti Medicush and Malva sinensis Cav.is restrained under Cd stress,low concentration of Cd to promote Malva rotundifolia L.'s photosynthesis,and high concentration of Cd inhibit its photosynthesis,and photosynthesis in Malva crispa L.was given a promotion under Cd stress.Malva crispa L.?Malva rotundifolia L.has stronger photosynthetic patience,but Abutilon theophrasti Medicush?Sida rhombifolia L.and Malva sinensis Cav.photosynthetic patience weaker under Cd stress.low concentration of Cd to promote Malva crispa L.and Abutilon theophrasti Medicush's photosynthetic pigment,and high concentration of Cd inhibit its photosynthetic pigment,Cd stress inhibits Sida rhombifolia L.'s chlorophyll synthesis,but promote the synthesis of the carotenoid,and Cd stress promote the synthesis of Malva rotundifolia L.and Malva sinensis Cav.photosynthetic pigment.3)SOD,POD play a major role for Plasma membrane peroxidation in Malva rotundifolia L.under Cd stress,Cd inhibits Sida rhombifolia L.and Abutilon theophrasti Medicush antioxidant enzyme activity,which make the plasmalemma peroxide degree deepening of plants,antioxidant enzymes(SOD,CAT,POD,APX)of Malva crispa L.play an important role for alleviating plasmalemma peroxide,Cd significantly inhibits Malva sinensis Cav.POD activity,and SOD?CAT and APX eased the plasmalemma peroxide.Malva rotundifolia L.has stronger antioxidant ability,Sida rhombifolia L.and Abutilon theophrasti Medicush's antioxidant ability is weaker.To sum up,Five kinds of plants have strong ability of tolerance and enrichment to Cadmium,they all can be used as ideal green material to phytoremediation of Cd contaminated soil.This study provides a theoretical basis for discovery of new plant material that repaired soil and plant physiological tolerance research to Cadmium stresses.