Research On The Drought Resistance Physiology And Relative Genes Of Sugarcane Seedling Root

Drought stress can bring changes on the levels of plants in shape、 physiology、 protein and gene expression, and it’s one of the main environmental factors of limiting plants growth. So studies on the drought-resistance mechanism in plants and their adaptation and adjustment mechanism under drought conditions will be of great significance on breeding new drought-resistance species of high efficiency and solving the current shortage of water resources and the deterioration of ecological environment. In the study, I have selected sugarcane ROC22for material, and gained a large number of candidate gene fragments related to drought resistance by comparing the drought-resistance structure of the sugarcane seedling roots under drought stress, constructing full-length cDNA library of the sugarcane seedling roots under drought stress and sequencing positive clones. The results will lay the foundation to clarify the physiological and molecular biological mechanisms of sugarcane roots drought-resident, and they can also provide a theoretical basis for a comprehensive understanding of the genetic basis of sugarcane drought resistance, cultivating the new varieties of drought resistance and developing drought cultivation techniques. The main research contents and results are as follows:1、With the extension of drought time and the increase of drought degree, root epidermal cells and cortical parenchyma cells both became smaller and their shapes also changed, the number of cortical cell layers reduced, the cells of endodermis and casparian strip became thicker, the pore size of column tube became larger, and the middle parenchyma cells reduced、 or even disappeared.2、With the increasing drought degree, the contents of proline and free amino acid were both on an upward trend, and a big increase in the late of the dry period; there was a significant difference when compared with the control groups at that time. The content of soluble sugar started to grow substantially in the mid to late period, there was also a significant difference when compared with the control groups; during the late of the dry period, the content of soluble sugar stoped growing and began to fall after it has increased to a certain extent.3、I have got523high-quality EST sequences from selection of526positive clones on random by constructing full-length cDNA library of the sugarcane seedling roots under drought stress, sequencing and screening; the468Uni-ESTs including29contigs and439singlets have been obtained respectively after sequence assembly splicing. By homology comparison,444Uni-ESTs were homologous or similar to known functional genes,24Uni-ESTs were homologous or similar to unknown functional genes, and55new sugarcane genes were not found homologies.