Gene Expression Profile And Physiological Adaptation Of Haloxylon Branch Under Heat Stress Of Environment

Greenhouse effect increased caused by the global warming of high-temperature stress is affecting the survival and growth of plants to abiotic stress one important factor. Ability to abiotic stress is strong and the most widely distributed of desert vegetation in the desert of Haloxylon. Summer temperature is very heat and drought in the desert. Studying on the heat resistance of Haloxylon is a concern. Most studies on physiological and biochemical mechanisms of the resistance in Haloxylon have been studied, however less resilience to study the molecular mechanism of Haloxylon. In this study to detect the physiological response and molecular adaptation mechanisms of wild Haloxylon on the summer heat stress.To grow at the end of May 2013 to the end of August in the wild desert Haloxylon for material, as the summer temperature changes to detect physiological responses in the main indicators of resilience. The results showed that as the summer the amount of water absorption is greater than transpiration, under high-temperature stress Haloxylon absorption capacity is drop, RWC of Haloxylon of psammophytes is decreased, the results indicated that under the appropriate temperature total chlorophyll content of Haloxylon with increased atmospheric temperature rises, when the atmospheric temperature is above a certain value, after high-temperature stress chlorophyll content decreased rapidly and remains at a low level.The study showed that with the temperature rises MDA content and conductivity content significantly increased of Haloxylon,high-temperature stress accumulation of reactive oxygen species of Haloxylon are more cause membrane damage. The results showed that under high-temperature stress in summer the dynamic transformation of free proline contents and soluble sugar contents of Haloxylon, soluble sugar contents and freeproline contents increased with warming, but soluble sugar content decreased with the temperatures fall. which showed that metabolism level of the above two substances in Haloxylon branch aroused a series of adapt ability changes. The study showed that the activities of SOD activity and POD activity were all builded up under the high-temperature stress, but CAT activity decreased. As the temperature increases the degree of change increases SOD(superoxide dismutase),POD(peroxidase) and CAT(catalase), which function is scavenging reactive active oxygen, are the system of protective enzymes in membrane. The results showed that the content in Haloxylon assimilation sticks of IAA in leaves decreased in the growing period of summer, In the early growing period, the content of ABA in sticks less when the temperature is appropriate, ABA content with the gradual rise in the temperature of the rapid accumulation, the content of GA3 with increasing temperature showed a declining trend.Drought and heat are the most important abiotic stresses, in this study, the objective of this experiment is to study the mechanism of drought and heat resistance in Haloxylon branch. Using Haloxylon branch under heat and optimum temperature as experimental material, the transcriptome of Haloxylon branch sequenced by using Illumina Solexa technology, and the functional annotations and metabolic pathways analyses of some unigenes were conducted in this present paper. The results indicated that 162504 unigenes length greater than 200 bp. Comparison with Nr and Swiss-Prot protein databases showed that 38529 and 23198 unigenes had homology with the genes from other species, respectively. The 13012 unigenes were able to be assigned to 25 categories with the KOG database. Functional annotation against KEGG database identified 22249 unigenes which were mapped to 298 metabolic pathways. The study indicated that the response of Haloxylon branch under drought and heat stress involved many genes and regulated by several collaborative biological processes, and changes of gene expression level maybe playimportant roles in regulation process, and will help to reveal and understand the mechanism of Haloxylon drought and heat stress tolerance The study also laid the foundation new genes related with drought and heat stress tolerance for Haloxylon.