Effects Of Heavy Metal Cu Stress On Seed Germination And Seedling Growth And Phvsiological Indices Of Hemp

Because large amounts of industrial Cu mines are exploited,industrial waste water are discharged,the agricultural production of Cu-producing chemicals frequently used,soil Cu pollution has become serious.Excess Cu can lead damage to organisms through the food chain.Hemp(Cannabis sativa L.)is a multi-use plant,used for textile,paper-making,military,chemical industry,building materials,food and pharmaceutical,and other aspects.Hemp can survive under poor environment,also it has large biomass,which make hemp as candidate plant for resolving the problems of Cu soils pollution.This paper studied the effects of different concentrations of Cu treatment on seed germination and seedling growth and physiology,as well as Cu accumulation in hemp root,stem and leaf,aiming at assessing the feasibility using hemp to rehabilitate copper contaminated soils.The growth response of Cu in germination period was studied by using the filter paper culture method,and the Cu stress tolerance of nine cultivars were evaluated by the membership function.Using Y1 and Y7 as materials,pot method is used to study the growth of seedling stage of Cu growth and physiological response and accumulation characteristics,for improved varieties,estimated different tolerance Cu hemp,this can demonstrate the application of some academic reference.The consequences were listed:(1)The influence of different Cu on germination of 9 hemp diversity(BM,Y1,Y5,Y6,Y7,YW6,W1,J1,Q1):1.Results showed that growth of germinating energy?germination rate?germination index?vigor index of Y6 and Y7 were not inhibited at low treatment(50 mg/L?100mg/L),which inhibited at high Cu treatment,however the other 8 species were obvious different with the control,which decreased with the raised Cu level.2.The root length,shoot length,fresh weight,lateral roots,root-shoot ratio gradually shorten with increasing Cu level,and were obvious different with the control.Inhibition index of root more bigger than shoot length,indicating the effect of Cu on the root was larger than on the shoot.under the treatment of 600 mg/L without lateral roots.3.Through average subordinate function different hemp Cu tolerence were classified: Y1?Q1?BM were low Cu-tolerance cultivars,J1?Y5?W1 were middle Cu-tolerance cultivars,Y6?YW6?Y7 were high Cu-tolerance cultivars.(2)Effects of different Cu treatment on seeding growth of two hemps(Y1 and Y7).1.With the increase of Cu concentration,the height and stem diameter of hemp Y1 and Y7 was decreasing.The difference of Y1 and Y7 on the height was not significant at 300 mg/kg,then was obvious different with the control with increasing Cu level,indicating there was a strong inhibition effect on the height under Cu stress.The difference of Y1 and Y7 on the stem diameter was not significant in 300-1500 mg/kg,indicating there was a low inhibition effect on the stem diameter under Cu stress.2.With increase of Cu treatment,the chlorophyll of Y1 and Y7 was decreasing,relative conductivity,MDA,soluble sugar,SOD were increasing.soluble protein of Y1 was decreasing,soluble protein of Y7 was increasing significantly different compared with control.the chlorophyll of Y7 at 300 mg/kg was increasing significantly compared with control,showing low concentration Cu promoted the chlorophyll of Y7;However,with the increase of stress,it was obvious that the physiological indexes of Y1 and Y7 were inhibited.3.Dry weight of root,stem,leaf of Y1 was decreasing obvious under Cu treatment,dry weight of root,stem,leaf of Y7 was increasing at first and then decreasing obvious under Cu treatment.The above indicated that Cu stress had a greater impact on dry weight.Accumulation characteristics of Cu in Y1 and Y7 under the Cu stress,Cu primarily accumulated in roots,the content of Cu in different part were listed:root>shoot>leaf.Meanwhile biological concentration factor(BCF)less than 1,So Y1 and Y7 was not plant of Cu super-rich.The Cu transfer factor(TF)and tolerance coefficient(RC)of Y1 were less than 1,The Cu TF and tolerance coefficient(RC)of Y7 were more than 1,indicating that Y7 had a high tolerance to Cu treatment.Totally Y1 was more sensitive to Cu than Y7.