| This study was conducted from2011to2012in the agronomy experimental station andState Key Laboratory of Crop Biology of Shandong Agricultural University, Taian, China.With twelve peanut (Arachis Hypogaea L) cultivars of five botanical types grown underartificial water control at seedling and pod-setting stage, the drought resistance relatedmorphology, physiological and biochemical traits of peanut leaves and roots were studied, torevel key drought resistance traits and the drought resistance mechanism of different peanutcultivars. Two water treatments were designed, that were40%and70%of the soil relativewater content at seedling stage and50%and70%of the soil relative water content of the0~80cm soil layer, respectively, at pod-setting stage. Weighing method andsupplemental irrigation based on testing soil water were adopted at seedling pod planting andpod-setting stage pond culture respectively. Then, identifying the drought resistance and traitsof forty main popularized cultivars of main peanut production area in China. The main resultsshowed that:1Changes of drought resistance and drought adaptability in different peanut cultivarsDrought resistance applied at seedling and pod-setting stage was basically identical.According to yield-drought resistance coefficient, sorting of twelve peanut cultivars was thatRugaoxiyangsheng> A596> Shanhua11> Nongda818> Huayu20> Shanhua9> Haihua1>79266> Penglaiyiwohou> Hua17> ICG6848> Baisha1016, which can be divided into3grads: high-resistance, including A596, Shanhua11and Rugaoxiyangsheng; mid-resistance,which were Huayu20, Nongda818, Haihua1, Shanhua9and79266; weak-resistance, asICG6848, Baisha1016, Hua17and Penglaiyiwohou. Rewatering after drought at seedling, thecapacity of compensatory growth was significant positive correlation with drought resistance (P<0.01), high drought adaptability cultivars were Shanhua11, Rugaoxiyangsheng, A596,Shanhua9, Nongda818, which were over-compensatory growth after rewatering.2Drought resistance mechanism of water balance and morphological traits in differentdrought resistant peanut cultivarsThe trend about dry weight, volume and absorbing area of roots was increased first andthen decreased, and root shoot ratio showed a growing trend with the drought processperformance. There were greater root morphological traits of the peanut cultivars with higherdrought resistance, throughout the course of the drought stress. Applied40%RWC droughtstress at10d-24d after germination, the root weight, volume, total absorption area per plantwere significantly positive correlated with drought resistance，which could identify thedrought resistance ability of peanuts root, it was suitable that identifying them under normalwater. Leaf area per plant, functional leaf area and stomatal conductance(Gs) were reduced,but SLW and Lswas increased under soil drought stress, so that reducing moisture loss andmaintaining moisture balance. The leaf area per plant and SLW of high-resistance cultivarswere significantly greater but functional leaf area were less than weak-resistance cultivarsunder both normal irrigation and drought stress. Haihua1, Shanhua9, Shanhua11and Huayu20presented as larger biomass and strong absorptive capacity, the ability of root waterabsorption was better. SLW of Rugaoxiyangsheng and Shanhua11were larger, stomatalregulation of Nongda818was optimal, which had better water retention. Shanhua9andHuayu20had larger photosynthesis area.3Physiological mechanism and related traits of drought resistance of different peanutcultivarsThe content of proline, soluble sugar, soluble protein were increased under drought stress,the amplification at seedling stage was greater than pod-setting stage, which were significantpositive correlation with osmotic adjustment ability (OA), the OA and its correlationcoefficient with drought resistance of seedling were greater than pod-setting stage. Justproline and drought resistance was significant positive correlation under both seedling andpod-setting stage. It was appropriate that identifying the OA of different peanut cultivars atseedling stage. Applied40%RWC drought stress at10d-24d after germination, The contentof proline and OA significantly positive correlated with drought resistance, A596,Rugaoxiyangsheng, Shanhua11, Nongda818were excellent than others. Photosynthetic rate(Pn), Gs, intercellular CO2concentration(Ci), maximumphotochemical efficiency(Fv/Fm), PSII actual quantum yield(ΦPSII), photochemical quenchingcoefficient(qP) were gradually decreased with the drought process, and that were graduallyincreased after rewatering, amplitudes of high-resistance cultivars were less than that ofweak-resistance. The recovery ability of Pn, Gs, ΦPSII, Fv/Fm, qPof Shanhua11,Rugaoxiyangsheng, A596and Shanhua9were faster than79266, ICG6848, Baisha1016andHua17, the former could recover to normal level in5d after rewatering and were higher thanthe control values in10d after rewatering, but the later could still not reach the normal valuesin10d after rewatering, photosynthetic parameters of the former were always higher than thelatter in the process of drought and rewatering(P<0.05). Correlation analysis showed that thedrought resistance significantly positive correlated with Pn, ΦPSII, Fv/Fm, qPin14d afterdrought stress and5d after rewatering, these traits could be used for identifies the damagedegree and repair capacity of peanuts. Pn、Ls、Fv/Fm、qPunder50%RWC drought stresssustained30d at pod-setting stage could stand for photosynthetic activity of peanut cultivars.In the process of drought stress, relative conductivity (RC) of peanut leaves showed atrend of increase gradually, which were very significant negative correlation with droughtresistance. The amplification of RC at seedling significantly less than pod-setting stage, thecoefficient of variation between cultivars was also. Antioxidase activity and antioxidantcontent of high-resistance cultivars leaves were significantly greater than weak-resistance, cellmembrane damage to a lesser degree. The anti-oxidation capability and correlation withdrought resistance of pod-setting stage were greater than seedling stage, it was appropriatethat identifying the anti-oxidation capability of different peanut cultivars at pod-setting stage.By correlation analysis, SOD activity, MDA content and relative conductivity of leaves under50%RWC drought stress sustained30d at pod-setting stage, were showed very significantlycorrelation with drought resistance coefficient. Under drought stress, antioxidase activity suchas SOD、POD、CAT and antioxidant content such as GSH and ASA of high-resistancecultivars were significantly greater than weak-resistance, but the content of MDA weresignificantly less than weak-resistance. Applied40%RWC drought stress at10d-24d aftergermination, the root SOD activities and MDA content were very significantly correlated withdrought resistance. Antioxidant ability and membrane stability of A596, Rugaoxiyangsheng, Shanhua11were preferable.4Technology system about identification of drought resistance and evalution of droughtresistance mechanism in different peanut cultivarsThe suitable relative soil water content of40%to identify drought resistance of peanutsat seedling stage, of50%to identify drought resistance of peanut at pod-setting stage, it wasappropriate to sustain stress14and30days respectively. Shanhua11and79266canrespectively serve as standard cultivar of high drought resistance and weaker droughtresistance identification. Shanhua11can serve as standard cultivar of drought resistance traitsidentification in peanut. The drought resistance mechanism of Shanhua11andRugaoxiyangsheng were excellent mutual compatibility. The main drought resistancemechanism of A596was the strong ability of OA and antioxidant capacity, of Shanhua9andHuayu20were better root water absorbing capacity, of Nongda818was higher leaf waterretention and osmotic regulation ability, of Haihua1was outstanding root water absorbingand ntioxidant capacity.According to the standard cultivar of drought resistance, in the40main cultivars, thehigh-resistance cultivars including0616(E1), Puhua28, Laibindadou and Shanhua11. Thekey drought resistance mechanism for higher SLW including Shanhua9, Shanhua12, Luhua11, Ji0212-4, Huayu25, for stronger OA including Shanhua7, Nongda073, Puhua28,Laibindadou, Fenghua1,0616(E1), for excellent resistance to oxidation including Xuzhou68-4, Shanhua10, Fenghua1,Weihua10, Laibindadou, for higher photosynthetic activityincluding Puhua28, Laibindadou,0616(E1), Shanhua12, Ji0212-4, Xuzhou68-4. |
PDF Full Text Request