Effects Of Lead Stress On Growth And Physiology Charactors Of Camellia Nitidissima Seeding

In this study,the method of pot experiment was used to study the seedlings of Camellia nitidissima under T1(0 mg · kg 1),T2(62.5 mg · kg 1),T3(125 mg · kg-1),T4,T5(250 mg ·kg-1)(500 mg · kg-1,),T6(1000 mg · kg-1),T7(2000 mg · kg-1)the seven different concentrations of lead nitrate solution stress Camellia nitidissima’s growth characteristics,physiological characteristics and photosynthetic characteristics,for analyzing the resistance ability of lead nitrate,exploring Camellia nitidissima of lead stress reaction and adaptation mechanisms.In order to provide reference for the selection of Camellia nitidissima in the cultivation area under heavy metal pollution.The results showed that:(1)In addition to the Camellia nitidissima tablets water content difference was not significant,different lead to Camellia nitidissima has a very significant influence in the growth index,at low concentrations(125 mg/kg)or less lead nitrate solution under duress,Camellia nitidissima seedling to lead stress has a certain resistance,seedling growth is good,when the treatment concentration exceeds 125 mg/kg,the growth of Camellia nitidissima is restrained,the increment of seedling height,diameter diameter,leaf area,leaf length,average width,above ground biomass,underground biomass,leaf fresh weight,leaf dry weight,relative water content of leaves and so on are the trend of decline.The lowest was at 2000 mg/kg.Comprehensive analysis shows that the strength of each treatment is:T3>T2>T1>T4>T5>T6>T7.(2)There was a significant difference between each physiological index in the treatment of lead nitrate.The MDA content,SOD,POD and CAT activity of Camellia nitidissima were all increased with the increase of lead concentration.At T2(62.5mg/kg),the minimum value was obtained when the maximum lead concentration was treated(2000mg/kg).The antioxidant enzyme activity of the seedlings of Camellia nitidissima was sensitive to lead nitrate stress.(3)The difference of the photosynthetic indexes of Camellia nitidissima under different lead nitrate treatments is extremely significant.The changes of chlorophyll a,chlorophyll b and chlorophyll total a+b,net photosynthetic rate,transpiration rate and respiration rate were all consistent.All of them reached the maximum when the concentration of lead nitrate was 62.5mg/kg.With the increase of lead concentration(greater than 62.5mg/kg),chlorophyll content,net photosynthetic rate,transpiration rate and stomatal conductance were decreased,which was less than the control.(4)Correlation analysis was carried out on the Camellia nitidissima each index,in addition to no significant correlation between the CAT activity,plant height,ground diameter relative increment,leaf area,leaf length,average width,Ye Xian heavy,authors,leaf relative water content,aspect ratio,dry weight of above ground and underground part of the dry weight,total biomass chlorophyll a and chlorophyll b,chlorophyll a + b,net photosynthetic rate,transpiration rate,stomatal conductance were extremely significant positive correlation between,and high aspect ratio,stem root ratio,POD,SOD,MDA,significant or very significant negative correlation.The analysis of the membership degree and the quality analysis of the seedlings were carried out,which showed that the resistance of Camellia nitidissima to the treatment of different concentrations of lead nitrate solution was stronger.In the treatment of 125mg/kg of lead nitrate concentration,the degree of membership was the largest,while T3(125mg.kg-1)was also the best,and the optimal shape index was the best.The results showed that the growth indexes of Camellia nitidissima were the best in the treatment of 125mg/kg.Comprehensive analysis and comparison show that low concentration of lead nitrate(125 mg/kg or less)to a certain extent promote the Camellia nitidissima seedling growth,but high levels of lead stress in Camellia nitidissima seedling growth was significantly suppressed.Therefore,the lead content of Camellia nitidissima was considered.It is suitable for growth in soil below 125 mg/kg.Camellia nitidissima has strong resistance to lead nitrate treatment,and has certain adaptability and patience to high concentration of lead stress.It can be popularized in places where some heavy metals are lightly contaminated.