| Tea plant is one of the important economic crops in our country,and tea is regarded as an agricultural product of Chinese important foreign exchange-earning.Due to natural and human factors,the loss of the tea plant germplasm resources becomes more and more serious because of the natural and factitious factors,especially to the 20th century,this process is accelerating for the rapid population growth,deforestation and land reclamation, economic construction and so on.At the same time,in general,tea plant reproduction use of cutting propagation in order to stabilize good character in heredity in tea production, however,well-bred spread made local seed fall to disuse in many places and non-economic outstanding germplasm loss,so it is of important significance to preserve properly and use of various types of tea plant for research and production of tea of current and future.But seed breeding in these areas has great advantages.Tea plant seed is natural reproduction itself with integrated genetic information,and it is very convenient to carry,transport and storage as the preservation of materials,and important to multiply and spread.Long-term preservation of seed is the key way for the prevention of cullinar degradation,so it is particularly important to study storage of tea seed.Most of the plant seeds can be stored in low water content(2%to 5%,or even lower) and low temperature or ultra-low temperature,but tea plant can not be stored for a long time in such a high moisture content for losing lives in the loss of more water(below the critical water content).At present,the research on dehydration to tea plant focuses on fields of physiology, biochemistry,cytology and so on in the process of dehydration.Dehydration has various damages to cell:the reason of senescence and death caused by dehydration is not clear,but the research of specific characteristic product related with the quality of tea is developing fast,but there is little research on the death for dehydration in molecular biology. Therefore,it is an important theoretical significance to illuminate the mechanism of senescence and death caused by dehydration for the research on the tea plant dehydration-related gene expression,and it laid theoretical foundation for preserving tea plant seeds with biotechnology in the future.We chose Longjing 43 as material,and focus on research:One is of the modal and physiological indicators when it is mature in tea plant; another is of the cloning,analysis the genes related to senescence and death caused by dehydration through fragments from derived transcript by cDNA-AFLP.The requirement of related to a number of factors not just a single one.It is of important significance to raise the seed tolerance of desiccation.The main results were as follows:The modal and physiological indicators,such as rate of water content and chlorophyll content,were observed and determined on Longjing 43 in the 7th weeks before maturity. The result showed that the rate of water content and chlorophyll content were about 36% and 0.2ng/g of mature Longjing 43 respectively.For studies of differential gene expression,cDNA-AFLP was analyzed in tea plant in the progress of dehydration.The result showed that,by NCBI in contrast with BLAST, differential fragments TDF1,TDF2,TDF3,TDF4 had high homology with putative senescence-associated protein,PPR protein,thioredoxin family protein and tumor protein respectively;the functions of two different segments were not clear.The full length of cDNA was 1061bp with the technology of RACE,and the nucleotide sequence and amino acid sequence deduced of this gene had high homology with senescence-associated protein compared with BLAST.
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