Detection Of Antioxidant Protection System In Winterwheat At Low Temperatures Induced By ABA

The winter wheat Dongnongdongmai1cμLtivar has an above85%winter survival rate and is the first winter wheat race grown in Heilongjiang province.lt can be resistant to-30℃. The mentioned above provides the guarantee us with northern winter of ecological environment construction. Cold stress generally induces oxidative damage to plants. Plants could adjust to adversity caused oxidative damage by enhancing antioxidant system containing antioxidative enzymes and nonenzymatic substances. So cold resistance is closely connected with antioxidant capacity.And the development of study on effect of exogenous abscisic acid on cold resistance and antioxidant activity, we explore the antioxidative mechanism of Dongnongdongmai1induced by ABA. There are the important oretical significance and application prospect for to further search after the strong cold resistance mechanism of Dongnongdongmai1and to get more of the high quality and more suitable for new cold material. In this test, we examined changes in the antioxidant content and gene expression levels of key enzymes involved in ASA-GSH cycle as temperatures dropped in Dongnongdongmai1.The samples were treated with exogenous abscisic acid. water and ABA inhibitor sodium tungstate. The antioxidant content are consist of AsA、total AsA、GSH、total GSH、AsA/DHA and GSH/GSSG and the activity of antioxidant enzyme.The key enzyme activity in ASA-GSH cycle including GR、DHAR、APX and MDHARwere also investigated by using Real-time PCR. Our main res μ Lts are as follows:1) The effects of cold stress on H2O2content and relative conductivity in leaves and tillering nodes of Dongnongdongmai1showed a rising trend. Appropriate ABA significantly inhibited oxidative damage caused low temperature. The ABA treatment effect with spraying foliage was superior to that with irrigating rhizosphere. When exogenous sodium tungstate was added, the degree of oxidative damage was conversed. Furthermore, the level of active oxygen in leaves was higher than that in trilling nodes.2) Suitable ABA induced a significant increase in non-enzymatic antioxidant contents and antioxidant enzyme activity. GSH、AsA、total AsA、total GSH content had a first increasing then decreaseing trend. In trilling nodes, these contens almost peaked on2010.12.22(-20℃), but the point of maximum were2010.11.30(-10℃) or2010.12.22(-20℃) in leaves, indicating that trilling nodes were alittle long compared to the storage time of the leaves. ABA pretreatment co μ Ld obviously increase the activity of SG、CAT、POD. Specifically, at late of cold stress, a low concentration of ABA could reduce these activities.However, AsA/DHA and GSH/GSSG showed similar trends as the temoerature fell further. At the same temperature, comparing with water, sodium tungstate resμLt in decrease of AsA/DHA and GSH/GSSG. Treatment with ABA could reverse the effect of sodium tungstate.3) According to changes in the level of active oxygen、non-enzymatic antioxidant contents and antioxidant enzyme activity at low temperature, we included that the optimum control of ABA was spraying foliage and10-5mol/L. ABA application induced pronounced increase in the activies and the expression levels of the key enzyme of AsA—GSH cycle including APX、GR、DHAR、 MDHAR. As the temperature dropped, they appeared firstly increasing and then dreaseing tread. In leves the activies and the expression levels of APX and DHAR peaked on2010.11.30(-10℃) and then dreased gradually, and GR and MDHAR reached a peak on2010.12.22(-20℃), with only a slight decrease after that. In trilling nodes the activies and the expression levels of GR and DHAR had the point of maximum on2010.11.30(-10℃),whereas that of APX and MDHAR was2010.12.22(-20℃).From the analysis of AEL of the key enzyme and correlation between gene expression, the level of expression of TaGR、TaAPX、TaDHAR both in leaves and trilling nodes were differenent. The correlation between gene expression of TaAPX、TaMDHAR and TaGR、 TaDHAR remained a higher level, suggesting that they were regμLated consistently.4) Using the method of integrate phytophysiology with molecμLar biotechnology, comprehensively showed ABA played an positive role in regulation of AsA—GSH cycle by ABA in winter wheat. Cold stress-inducd ABA accumulation could increase the the activies and the expression levels of APX、GR、DHAR and MDHAR,which,in turn, enhanced the antioxidant ability and protected winter wheat against oxidative damge induced by cold sress. At the same time, the res μ Lts of our research might indicate that ABA involved in the expression level of the key enzyme in AsA—GSH cycle was the main way regulated by ABA at low temperature.