Analysis On Some Physiological Effects And Differential Proteome Of The Different Chinese Fir Clones Under Drought Stress

Due to the change of global climate, massive changes also happen to the environment where plantslive in. Among all the abiotic stresses, drought does the greatest harm to plants, which seriously effect thegrowth, development, biological yield and distribution. The Chinese fir is a fine commercial tree speciesunique to China. Owing to its characteristics of fast growing, fine quality, wide usage and high yield, theChinese fir has always been a primary reproducing tree species in the provinces of south China. In recentyears, seasonal drought frequently hit the red earth areas in south and brought serious impact to the growthof Chinese fir, which makes it really important to conduct a research on the drought resistance of Chinesefir. Considering this, this research tries to stimulate drought stress with PEG-6000and chooses the twokinds of Chinese fir clones including the drought-enduring FS43and the sensitive FS38as experimentalmaterials. Based on these, the research explores into the responses of drought stress to the Externalmorphology of these two poplar clones, as well as to such physiological processes such as the relativewater content, water-holding capacity, transpiration rate and chlorophyll fluorescence parameters. Besides,two-dimensional gel electrophoresis is also adopted to make an analysis of the differential proteomes ofleaves of the two Chinese fir clones under drought stress. The main research results are as follows:By comparing the External morphology change of the drought-enduring FS43Chinese fir and thesensitive FS38Chinese fir under drought stress, it is found that, with the extension of drought stress time,leaves of both the two Chinese fir clones have withered, yet there is a difference in leaf water loss. Thesensitive FS38Chinese fir suffers from severe water loss, their leaves curve, and most of the tender leaveson top wither.By studying some physiological processes of the drought-enduring and sensitive Chinese fir clonesunder drought stress, it is found that, with the extension of drought stress time, the relative leaf watercontents of the two Chinese fir clones gradually decrease, percentages of leaf water loss fall, transpirationrates first fall and then rise, and the Fv/Fm value gradually decrease. However, there is a difference invariation amplitude of physiological indice of different clones. The leaf relative water content, leaf waterloss percentage, transpiration rate and Fv/Fm value of the drought-enduring FS43Chinese fir are all belowthose of the sensitive FS38Chinese fir. After optimizing the two-dimensional electrophoresis system of leaf protein of Chinese fir, it is foundthat: The TCA-acetone precipitation method, which adds10%PVP in the process of grinding caneffectively eliminate large amounts of secondary substances; lysate containing thiourea and urea canachieve good protein dissolution effect; sample quantities with250μg/24cm IPG gel can get good2-DEmaps and raise resolution ratio; in IPG equilibrium,250mg of iodoacetamide is enough to raise thedefinition and resolution of protein spots; to stain coomassie brilliant blue can get a good staining effect on2-DE maps.By using the two-dimensional electrophoresis technology, this research studies the differential leafprotein expression of the drought-enduring FS43and the sensitive FS38Chinese fir clones under droughtstress, and screens out a total of24differentially expressed protein spots. After a MALDI-TOF-TOFtandem mass spectrometry analysis of these proteins, a total of5protein spots are identified, which fall intofour categories:a) enzymes related to the photoreaction and carbon reaction of photosynthesis: chlorophylla/b binding protein, ribulose-1,5-bisphosphate carboxylase/oxygenase large subunit; b) enzymes related tothe synthetizing of infiltration protection substances: myo-inositol-1-phosphate synthase; c) enzymesrelated to the material metabolism: granule bound starch synthase I; d) enzymes closely related to theantioxidation: peroxidase. Under drought stress, these differentially expressed protein spots may form asignal transmission system and interaction system, so as to adjust the photosynthesis, membrane stability,material metabolism and antioxidative metabolism of Chinese fir cells. The results of the experimentprovide us with the theoretical basis for our study of the molecular response mechanism of Chinese fir todrought.