Drought Resistance Of Different Oat Cultivars To Water Stress Physiological Response Mechanism

In this paper, method of membership function is used to evaluate drought resistance of21oat cultivars. This paper studies the effect of water stress on growth and developmengt, dry matter accumulation, physiological characteristics in root and leaf,photosynthetic characterics,yield and quality of different oat cultivars at jointing stage and heading stage. In order to know the physiological differences of drought resistance of different oat cultivars under water stress, the trails aim is to provide theoretical basis for oat drought resistance breeding and water saving and high yield cultivation. The results showed that:(1) According to the methord of membership function,21oat cultivars which were widely planted in Inner Mongolia’s main producing area can be divided into four classes, they are strong drought resistance, drought resistance, moderate drought resistance and weak drought resistance. Mengyanl and Qingyoujiu440are strong drought resistance cultivars; large oat, Youmai4400, Yan2006, Yan2004and Yankel are drought resistance cultivars; Paul, Neiyan3, Baiiyan2, Baiyan7, Bayoul, Caoyoul, Xinyuan oat and Baiyan10are moderate drought resistance; Baiyan4, Baiyan8, Bayou3, Bayou8, Jizhangyou2, Neinongdayoul are weak drought resistance cultivars.(2) With the increasing of water stress gradient, the plant height, leaf area and dry matter accumulation of two cultivars are reduced. Under sereve water stress, the decrease change of drought resistance cultivar Mengyanl on plant height, plant height, leaf area and dry matter accumulation is less than that of moisture sensitive cultivar Bayou3. Compared with Bayou3, the decrease change of Mengyanl on plant height, leaf area and dry matter accumulation reduced3.9,14.2and6.6percentage point at jointing stage, and that reduce10.9,3and1.9percentage point at heading stage.(3)With the increasing of water stress gradient, RWC, REC, MDA, soluble sugar, praline and POD of two cultivars are increased at two stage. The increase change of drought resistance cultivar Mengyanl on RWC, REC, MDA and soluble sugar is less than that of moisture sensitive cultivar Bayou3. But The increase change of drought resistance cultivar Mengyanl on POD and proline is more than that of moisture sensitive cultivar Bayou3. SOD activity and root activity increased first than decreased, The increase change of Mengyanl on SOD and root activity is more than that of Bayou3. Under sereve water stress, the decrease change of Mengyanl on SOD and root activity is less than that of Bayou3.(4)With the increasing of water stress gradient, the Photosynthetic rate and Chlorophyll content of Mengyanl first increased than decreased, but that of Bayou3reduced. Under sereve water stress, the decrease change of Mengyanl on Chlorophyll content, Photosynthetic rate, Transpiration rate, Intercellular CO2concentration and stomatal conductance is less than that of Bayou3. Compared with Bayou3, the decrease change of Mengyanl on Chlorophyll content, Photosynthetic rate, Transpiration rate, Intercellular CO2concentration and stomatal conductance reduce4.8,11.4,17.6,13.8and14.6percentage point at jointing stage, and that reduce28.4、12.2,4.1,19and35.8percentage point at heading stage.(5)Water shortage at jointing stage will influence the formation of the effective spike number, with the increasing of water stress gradient, yield factors and yield of two cultivars decreased. Under sereve water stress, the decrease change of Mengyanl on effective spike number, spike grain weight, spike grain number and hundred grain weight is less than that of Bayou3. Compared with Bayou3, the decrease change of Mengyanl on effective spike number, spike grain weight, spike grain number and hundred grain weight reduce-8.1,29.7,10.9and14.7percentage point at jointing stage, and that reduce1.4,43,9.3and29percentage point at heading stage. Under mild water control, the yield of Mengyanl increased, the increase change of Mengyanl is2.8times that of Byou3.(6)The grain protein content of two cultivars is accumulated more at heading stage. Under sereve water stress, compared with Bayou3,the grain protein content of Mengyanl improved3.07percentage point. Under sereve water stress, the decrease change of Mengyanl on β-glucan content is less than that of Bayou3. Compared with Bayou3, the decrease change of Mengyanl on eβ-glucan content reduce19percentage point at jointing stage, and that reduce35.8percentage point at heading stage.(7)Oat yield with REC and POD in roots, RWC in leaves and Photosynthetic rate, Transpiration rate exist extremely significant correlation, it with soluble sugar in roots and REC in leaves exist significant correlation, there is no significant correlation between oat yield and other indexes. So REC and POD in roots, RWC in leaves and Photosynthetic rate, Transpiration rate could be used as identification indicators of drought resistance.