Study On The Effect Of Copper,Cadmium And Lead In Soils On The Growth Of Tea Plant In Shaanxi Province

The tea is the traditional drinks of Chinese, there are 3000years for us to use and drink it. Tea has been known to health, now there are more than 20 million people drink tea. With the growth of economic, environmental pollutants emission is increasing,the environmental pollution are getting serious. In recent years, more and more report about heavy metals in tea and pesticide residue. Not only affects the quality of tea, and enter the body through the food chain and it's harmful to our health, it also become the biggest obstacle to China's tea exports. Therefore, the research on the content and distribution of heavy metal in tea gardens and the effect on the growth of tea plant and the quality of tea, It's of great significance in tea production. In natural, the compound pollution is the main forms.The mechanism of the compound pollution of heavy metals in soil is so complex,it has additive, antagonism and synergism etc. Therefore, the study on compound pollution of heavy metals has more theoretical and practical significance.The research shows the content of these three heavy metals in soils ,teas and the plant of tea, their contents were then compared to standards of Non-pollution Tea codes.The correlation of heavy metal contents among the soil,tea samples and different organs of tea plants were evaluated.Under potted plant experiments with different concentration levels of heavy metals and determine the physiological and biochemical of tea,heavy metals in different parts of tea, in understanding the characteristics in accumulation and absorption caused by heavy metals, heavy metals interaction on the physiological indexes of tea.controlling the heavy metal pollution and improving the tea quality.The research aimed to provide necessary references for the healthy growth of Shannxi tea industry.The results of the present study are given as follows:â’ˆThe content of heavy metal of soils is different in different regions and depths of Shaanxi.Generally speaking,the heavy metal contents of tea garden soils in the study area were at low levels compared to the permitted values given by the Codes. The single factor pollution indexes was below 0.6 and Nemerow pollution indices was below 1. 0.â’‰The average contents of heavy metals in the tea products were in the magnitudes given by the Organic Tea Code.But the Pb content of some samples were close to the critical value given by the code.â’ŠThere were remarkable differences of heavy metals content in different organs of tea plant.The contents of Cu was highest in new shoots.The contents of Cd and Pb had the highest values in the branches. The contents of Cd, Pb in the roots had the second highest values.â’‹There was a significant positive correlations between the contents in the soil of Cd and Pb. The pH had a little correlation with the heavy metals contents.The correlation analysis showed that the content of heavy metals in tea was not significantly correlated with it in soils except Pb.â’ŒEffects of different heavy metals compound pollution showed that Cadmium had a synergism effect with Copper, Lead had an antagonistic effect with Cadmium and Copper in a certain concentration range.