【作者】 张鑫；

【导师】 王振林； 李勇；

【作者基本信息】 山东农业大学 ， 作物栽培学与耕作学， 2019， 硕士

【摘要】 黄淮海区域是我国小麦的主产区,降雨季节分布不均,小麦生长季年均降雨量仅占其全生育期需水量的35%-50%。灌浆期间干旱频发对籽粒产量的影响尤为显著。因此,本试验通过研究干旱逆境下外源脱落酸（ABA）对小麦光能利用与同化物转运的调控作用,探讨外源ABA对干旱条件下不同基因型小麦花后冠层温度和同化物积累与分配的影响,为提高小麦稳产抗逆性及花后延衰增粒重提供理论依据。本试验于2016-2018年在山东农业大学试验农场遮雨棚水分池内进行,主区为品种,供试品种为水分敏感型品系辐287（F287）和耐旱型品种山农20（SN20）。副区设置正常灌水条件（田间持水量的75%-80%,W）和水分胁迫条件（田间持水量的40%-50%,D）。副副区设置外源激素处理,花后连续4天喷施10 mg·L^-1外源脱落酸（ABA）,用量为100 mL·m^-2,以喷施含0.5%（V/V）Tween-20的清水为对照（CK）。主要研究结果如下:1.外源ABA对干旱条件下小麦冠层温度的影响干旱处理显著提高两品种的叶、穗温及穗叶温差（SLTD）,显著降低冠层温差（CTD）。整个灌浆期间,山农20的叶温显著高于辐287,穗温显著低于辐287。灌浆中后期山农20的CTD及SLTD均显著低于辐287,说明耐旱型品种叶片的水热损失较小。喷施外源ABA可以显著提高两品种叶温,显著降低穗温、CTD和SLTD。品种与ABA互作对SLTD影响显著,水分条件与ABA互作对CTD和SLTD造成显著影响。2.外源ABA对干旱条件下小麦光合机构活性的影响干旱处理后两品种PI_abs（吸收光能性能指数）及φ₀（捕获电子传递到电子传递链Q_A^-中下游的其它电子受体概率）均出现显著降低,尤其在灌浆后期,二者降幅均达到50%以上。整个灌浆期间山农20的PI_abs值和φ₀值均高于辐287,说明耐旱型品种吸收光能及传递电子的能力较强。喷施ABA能显著提高PI_abs值和φ₀值,说明喷施ABA可以改善光合机构活性,从而为光合作用吸收更多光能和同化力。干旱处理下两品种psbA基因相对表达量均显著降低。整个灌浆期间,干旱处理下山农20的psbA基因相对表达量均显著高于辐287,说明耐旱型品种较水分敏感型品种受水分胁迫影响较小,可以维持正常的psbA基因表达水平来合成更多D1蛋白,以保持其光系统活性。喷施外源ABA可以显著减小psbA基因相对表达量的降幅。与DCK处理相比,外源ABA处理下辐287和山农20的psbA基因相对表达量分别升高56.64%和29.29%。3.外源ABA对干旱条件下小麦光合能力的影响干旱处理后两品种净光合速率（P_N）、气孔导度（g_s）、蒸腾速率（T_r）显著降低,在中后期降幅更大。羧化效率（CE）呈现先升高再降低的趋势,在花后21天左右达最大值,灌浆中后期山农20旗叶的CE较为稳定。干旱处理下辐287的叶片水分利用效率（WUE_L）显著低于正常灌水处理,相反,山农20的WUE_L呈现小幅升高趋势。外源ABA能显著提高两品种的WUE_L、P_N和CE,显著降低g_s和T_r。与DCK处理相比,DABA处理下辐287和山农20的P_N分别提高了53.35%和31.31%,g_s分别降低35.46%和47.74%,T_r分别降低19.34%和32.23%。说明外源ABA通过降低叶片g_s和T_r以增强叶片保水性能,以提高旗叶的光合能力并延长其光合持续时间。4.外源ABA对干旱条件下小麦籽粒灌浆的影响干旱处理显著降低了两品种强、弱势粒重,中后期降低幅度更大。与WCK处理相比,DCK处理下辐287的最大灌浆速率、平均灌浆速率及生长活跃期均显著减小,山农20的最大灌浆速率、平均灌浆速率显著减小。说明干旱条件下水分敏感型品种是通过降低籽粒灌浆速率并缩短生长活跃期引起导致粒重降低的,而耐旱型品种主要是通过降低籽粒灌浆速率来引发粒重降低。与DCK处理相比,外源ABA处理后两品种强势粒最大灌浆速率、平均灌浆速率、生长活跃期及实际灌浆终期均有所提高,说明ABA处理后粒重的增加主要是由于其可以促进籽粒灌浆,提高灌浆速率并延长生长活跃期。5.外源ABA对干旱条件下小麦干物质积累与分配以及产量的影响干旱条件下两品种植株总重及粒重均出现显著降低。与WCK处理相比,DCK处理后两品种花后干物质转运量及花后贮藏同化物转运量对籽粒的贡献率均显著降低,水分敏感型品种降幅大于耐旱型品种。与DCK处理相比,DABA处理显著提高了花后干物质转运量及花后同化物转运量对籽粒的贡献率,表明灌浆期发生干旱时,耐旱型品种籽粒中的干物质主要来源于花后干物质积累,水分敏感型品种籽粒干物质来源于营养器官花前贮藏同化物的转运和花后干物质的积累。干旱处理下两品种产量均显著低于正常灌水处理,水分敏感型品系辐287千粒重和产量的降幅均高于耐旱型品种山农20。喷施ABA可以缓解干旱对千粒重的降低幅度。品种、水分和ABA均对粒重和产量影响极显著（P<0.01）,品种水分互作及水分ABA互作对粒重和产量造成显著影响（P<0.05）。更多还原

【Abstract】 The Huang-Huai-Hai area is the main producing area of wheat in China.The rainfall season was unevenly distributed.The average annual rainfall during the growing season of wheat accounted for only 35%-50%of the water requirement during the whole growth period.Therefore,this experiment studied the regulation of exogenous ABA on the radiation and photoassimilates transportation wheat under drought stress.The effects of exogenous ABA on canopy temperature and assimilates accumulation and distribution of different genotypes of wheat under drought conditions was investigated.Aiming to supply theoretical basis for improving the stress resistance of stable yield and the weight gain after anthesis.The experiment was carried out in the shelter pool of the experimental farm of Shandong Agricultural University in Shandong Tai’an,Shandong Province from 2016-2018.The water sensitive variety Fu 287（F287）and the drought-tolerant variety Shannong 20（SN20）were selected in this experiment.The experiment was conduct with two water gradients,normal irrigation conditions（75%-80%of the field moisture capacity,expressed in W）and water stress conditions（40%-50%of the field moisture capacity,indicated by D）.The experiment also set up exogenous hormone treatment.At the beginning of the flowering period,10 mg·L^-1exogenous ABA（American Sigma）was sprayed at a rate of 100 mL·m^-2 for 4 days after anthesis（DAA）.The water containing 0.5%（V/V）Tween-20 was sprayed as a control（CK）.The main results were as follows:1.The effects of exogenous ABA on canopy temperature of wheat under drought conditionsAfter drought treatment,the leaf and spike temperature of the two varieties was significantly increased,resulting in a significant decrease in canopy temperature depression（CTD）and a significant increase in the spike-leaf temperature depression（SLTD）.During the whole grain filling stage,the leaf temperature of SN20 was significantly higher than that of F287,and the spike temperature was significantly lower than that of F287.The CTD and SLTD of SN20 in the middle and late filling stage were significantly lower than those of F287.It indicated that the heat dissipation of leaves of drought-tolerant varieties was lower than that of water-sensitive varieties.Spraying exogenous ABA could significantly increase the leaf temperature of the two varieties and significantly reduce the spike temperature,CTD and SLTD.The interaction between cultivars and ABA had significant effects on SLTD,and the interaction between water conditions and ABA had significant effects on CTD and SLTD.2.The effects of exogenous ABA on photosynthetic mechanism activity of wheat under drought conditionThe PI_abs（the photosynthetic performance index）andφ₀（the probability that a trapped exaction transfers an electron into the electron transport chain beyond Q_A^-）of the two varieties were significantly reduced under drought condition,especially in the late filling stage,both of which decreased by 50%the above.The PI_abs andφ₀ value of SN20 were higher than that of F287 during the filling stage.It showed that drought-tolerant varieties have stronger ability to absorb light energy and transmit electrons than water-sensitive varieties.Spraying ABA could significantly increase the PI_abs and theφ₀ value.It showed that spraying ABA can improve the activity of photosynthetic mechanism,thus providing more light energy and assimilation force for optical contracting.The relative expression levels of psbA genes in both varieties were significantly reduced under drought treatment.During the whole grain filling stage,the relative expression of psbA gene in SN20 under drought treatment was significantly higher than that in F287.This indicated that drought-tolerant varieties were less affected by water stress than water-sensitive varieties,and could maintain normal psbA gene expression levels to synthesize more D1 proteins to maintain their photosystem activity.Exogenous ABA significantly reduced the relative expression of psbA gene.Compared with DCK treatment,the relative expression levels of psbA gene in F287 and SN20 increased by56.64%and 29.29%,respectively.3.The effects of exogenous ABA on the photosynthetic assimilative power of wheat under drought conditionsAfter drought treatment,the net photosynthetic rate（P_N）,stomatal conductance（g_s）and transpiration rate（T_r）of the two varieties decreased significantly,and the decrease was larger in the middle and late stages.The carboxylation efficiency（CE）of both varieties after anthesis increased and then decreased,reaching a maximum at 21 DAA.The leaf water use efficiency（WUE_L）of F287 under the drought treatment was significantly lower than that of the normal irrigation treatment.On the contrary,the WUE_L of SN20 under the drought treatment showed a slight increase trend.the CE of flag leaf of drought-tolerant varieties in the middle and late filling stage is relatively stable.Spraying ABA significantly increased WUE_L,P_N,CE and significantly reduced g_s,T_r.At 21 DAA,Compared with DCK treatment,the P_N of exogenous ABA treatment under F287 and SN20 increased by 53.35%and 31.31%,and g_s decreased by 35.46%and 47.74%,and T_r decreased by 19.34%and 32.23%,respectively.It is indicated that exogenous ABA could enhance the water retention capacity of leaves by reducing the leaves g_s and T_r,so as to improve the photosynthetic capacity of flag leaves and prolong the photosynthetic duration.4.The effects of exogenous ABA on grain filling of wheat varieties under drought conditionDrought treatment significantly reduced the strong and weak grain weight of the two varieties,and the reduction was greater in the middle and late stages.Compared with WCK treatment,the maximum grain filling rate,average grain filling rate and active growth stage of F287 were significantly reduced,and the maximum grain filling rate and average grain filling rate of SN20 were significantly reduced.It indicated that the water-sensitive varieties reduced the grain weight by reducing the grain filling rate and shortening the active growth stage under drought condition.The drought-tolerant varieties mainly reduced the grain weight by reducing the grain filling rate.Compared with DCK treatment,the maximum grain filling rate,average grain filling rate,active growth stage and actual grain filling stage of the two varieties were increased after exogenous ABA treatment.It indicated that the increase of grain weight after ABA treatment was mainly due to its ability to promote grain filling,increase the filling rate and prolong the active growth stage.5.The effects of exogenous ABA on dry matter accumulation and distribution and yield of wheat varieties under drought stressThe total weight and grain weight of the two varieties were significantly reduced under drought condition.Compared with WCK treatment,the dry matter translocation and post-anthesis storage capacity of the two varieties after the DCK treatment significantly decreased the contribution rate to the grain,and the moisture sensitive variety decreased more than the drought-tolerant variety.Compared with DCK treatment,DABA treatment significantly increased the contribution of post-anthesis dry matter transport and post-anthesis assimilate transport to grain.It indicated that the dry matter in the drought-tolerant varietiy mainly originated from the dry matter accumulation after anthesis,and the water-sensitive varietiy dry matter was derived from the transport of the pre-flowering storage assimilates of the vegetative organs and the accumulation of dry matter after anthesis.The yields of the two cultivars were significantly lower than that of normal irrigation under drought treatment.The water-sensitive cultivars F287 had a higher yield than the drought-tolerant variety SN20.Spraying ABA could alleviate the reduction of drought to1000-grain weight.In a word,significant effects on grain weight and yield were obtained from interaction treatment between exogenous ABA and variety,water condition（P<0.01）.Interaction between Variety and water conditon and interaction between water condition and ABA had significant effects on grain weight and yield（P<0.05）.更多还原