The Differences Of Characteristic Ingredients And Gene Expression In Young Sprout Of Tea Plants Cultured In Hydroponics Under Lead Stress

Lead polluting tea garden environment, and finally residue in tea products, become one of the main risk factors that affect tea quality and safety. Making a study of characteristics of absorption cumulative lead in tea plants by tea cultivation Physiology, probing into tolerance and resistance mechanisms of lead in tea plants,is an important subject of tea quality safely. When the content of heavy mental accumulated by tea tree exceeds toxicity threshold, the growth, agronomic characters, absorption and genetic expression of tea tree change,which is the symptoms of tea tree (the tea tree’s reactions to the heavy metal’s toxic). Do research in the differences of characteristic ingredients and gene expression in young sprout of tea plants cultured in hydroponics. Aims to explore the physiological and biochemical diagnostic marker and methods of tea plangts under lead stress,and reveal the tea patience and detoxification mechanisms to lead hazards.Using different disciplines in this topics, such as biochemistry of tea, coordination chemistry, phytophysiology, molecular biology and so on, this research analysed the features component content of tea tree leaf and the correlation with the lead accumulating under lead stress with different dose. Based on the metabolism changes of features component, complexation test was used, clarifying the associate effect between the features component and lead. Meanwhile, the content change of proteins has been researched, preliminarily analysing the difference of proteins and the change of amino acid composition. And the interaction of amino acid in vitro was studied. Finally, differential gene expression of turning-point new shoots was analyzed by differential display reverse transcription (DDRT). In this paper, the major results were summarized as follows:(1)Damage symptoms tea plant mainly perform:tea tree growth retardation,shoots water loss and wilting, edge of the shrinkage and curled into a spoon-shaped downward, until to scorch;mature leaf yellowing and chlorosis, accelerated shedding, few leaves have spots appear; root browning gradually darken until rot, surface attached to a large number of white flocculent,sticky substance;with the increase of lead concentration of, poisoning symptoms become more pronounced, eventually leading to the tea tree death.(2) Lead accumulating in mature leaves was significantly higher than that in shoots under lead stress with different dose in hydroponic tea tree, and it’s highest when the lead concentration was50mg/L. The features component content of mature leaves and shoots was significantly different. In shoots, the correlation sequence with the lead accumulating was soluble sugar, the water extract, tea polyphenol, soluble protein and catechin. Correlation coefficients are0.598、0.567、0.555、0.552and0.549respectively. They are much the same in mature leaves. The result by complexation test showed that the tea polyphenol, tea polysaccharide and cellulose with high correlation can adsorb, chelate and subside the lead.(3) The content of protein declined overall in leaves and shoots under lead stress. Also, there maybe some differentially expressed proteins in the turning-point samples. In shoots, the content was significant differences on free amino acid and all amino acid, and it’s also significant differences among each amino acid components. Glutamic acid, aspartic acid and serine besides proline and alanine were found the highest correlation with the total amino acids and the lead accumulating. Moreover, the synthesis pathways of α-ketoglutaric acid, oxaloacetic acid and hydroxy-pyruvic acid were significant differences, suggesting photosynthesis and respiration was affected in tea trees. In mature leaves, the content on free amino acid and all amino acid was somewhat different. In the interaction of amino acid in vitro, the typical amino acid reacted with lead to get the complex, and changed the UV-VIS scanning spectrum.(4) Using improved RNA extraction method and enhanced specific third generation primers, three turning-point samples were studied by DDRT. The result showed that the shoot gene at the level of transcription was changed under lead stress with different dose. The gene with different expression was selected and contrasted by Blast, finding that the gene was similar to controled serine/threonine protein kinase family and hypothetical protein of grape. The former is one of signal transduction factors concerning the growth and metabolism of plant, relating with metabolic changes, protein synthesis and genetic changes. In shoots, the expression changes under lead stress may related with physiology, biochemistry and metabolic changes.In conclusion, the sorption and accumulating of lead in the tea tree, also the mechanism of tolerance and detoxification were revealed in this research. It also provided the correlation between genetic expression and the features component, proteins, amino acid metabolism, establishing the foundation for cloning the heavy metals-resistant gene and studying molecular physiology in the tea tree.