【作者】 张宁；

【导师】 陈佰鸿；

【作者基本信息】 甘肃农业大学 ， 园艺（果树学）， 2021， 硕士

【摘要】 植物的向光性是植物对蓝光的向性反应,在植物界中广泛存在着向光性反应。葡萄作为一种喜光植物,具有明显的向光性。通过用赤霉素处理葡萄叶片,发现赤霉素对叶片的向光性有抑制作用。因此本研究以6年生?意斯林‘（Italian Riesling）葡萄为试材,选择晴朗的天气,选取生长健壮且无病虫害的植株,于8:00前将长度超过80 cm的新蔓去除副梢后拉平用塑料胶带固定在立架的第三道铁丝上,使叶片正面向下、背面向上,叶片呈水平状态,然后对固定后的叶片喷施药剂进行处理,共设3个处理,分别为75 mg/L的赤霉素（GA₃）、200 mg/L的烯效唑（S3307）和清水（CK）。处理后观察并测定叶片的旋转进程,同时测定叶片的水势、光合参数、叶绿素荧光参数、卡尔文循环关键酶活性及其基因的表达量、内源激素含量及GA信号传导途径关键基因的表达量等指标的日变化,探究外源GA₃对葡萄叶片向光性的调控机理,以期为进一步研究外源激素对叶片向光性的影响提供一定的理论基础。主要研究结果如下:1.随着光照时数的变化叶片逐渐发生旋转,叶片与水平面的夹角逐渐增大,叶柄与水平面的夹角逐渐减小。外源GA₃处理后较对照显著减缓了叶片的向光性旋转速度,而其抑制剂S3307处理则加速了叶片的向光性旋转。2.在外源GA₃减缓叶片向光性旋转的过程中,测定发现该处理的叶片水势在10:00-18:00时显著低于对照,而其抑制剂S3307处理后,叶片的水势在14:00-16:00时显著高于对照。3.外源GA₃处理后,叶片和叶柄卡中尔文循环过程的关键酶Rubisco、FBPase、GAPDH和FBA的活性及其基因表达量较对照显著降低;同时,叶片的光合参数Pn、Gs、Tr在12:00-18:00时较对照显著降低,Ci的变化则与Pn、Gs和Tr相反;叶绿素荧光参数Fm、Fv/Fm、ETR出现不同程度的降低,NPQ较对照显著升高。而其抑制剂S3307处理效果则与GA₃相反。表明GA₃对叶片的向光性旋转产生的抑制作用与其负调控光合作用相关调控基因,减弱叶片和叶柄的光合能力,降低光合产物的积累量有关。4.外源GA₃处理后,GA在叶片和叶柄中通过信号传导,引起了GA信号传导途径中的关键蛋白基因Vv GAI1、Vv RGA、Vv SLR1及Vv GID1A表达量的降低,提高了叶片和叶柄中GA₃、IAA和ZT的含量及GA₃/IAA的比值,降低了ABA的含量。由此可见,GA₃对叶片的向光性旋转产生的抑制作用与其调控内源激素的含量,提高叶片和叶柄中GA₃/IAA的比值有关。综上所述,外源GA₃通过降低叶片和叶柄的光合作用和光合产物的积累,提高内源GA₃与IAA的比值,进而对叶片的向光性旋转产生了一定的抑制作用。更多还原

【Abstract】 The phototropism of plants is the tropic response of plants to blue light,and phototropism is widespread in the plant kingdom.As a kind of light-loving plant,grape has obvious phototropism.By treating grape leaves with gibberellin,it was found that gibberellin has an inhibitory effect on the phototropism of leaves.Therefore,this study chose 6-year-old’Italian Riesling’grapes as the test material,and selected robust plants without diseases and insect pests on sunny days,remove the secondary shoots of new tendrils over 80 cm in length before 8:00 and then flatten them and fix them on the third wire of the vertical frame with plastic tape.Make the leaves face down and back up,and the leaves were in a horizontal state.And then spray the fixed leaves with chemicals.There are 3 treatments,namely 75 mg/L gibberellin（GA₃）,200 mg/L uniconazole（S3307）and clear water（CK）.After treatment,the rotation process of leaves was observed and measured.At the same time,the diurnal changes of water potential,photosynthetic parameters,chlorophyll fluorescence parameters,Calvin cycle key enzyme activities and the expression levels of genes,endogenous hormone content and the expression levels of key genes in GA signal transfection pathway were measured.By exploring the regulation mechanism of exogenous GA₃ on the phototropism of grape leaves,in order to provide a certain theoretical basis for further research on the influence of exogenous hormones on the phototropism of leaves.The main findings are as follows:1.With the change of lighting hours,the leaves gradually rotate,the angle between the leaf and the horizontal plane gradually increases,and the angle between the petiole and the horizontal plane gradually decreases.The exogenous GA₃treatment significantly slowed down the phototropic rotation speed of the leaves compared with the control,while the inhibitor S3307 treatment accelerated the phototropic rotation of the leaves.2.In the process of exogenous GA₃ slowing down the photosynthetic rotation of the leaves,the measurement found that the water potential of the treated leaves was significantly lower than that of the control at 10:00-18:00,and the water potential of the leaves after treatment with its inhibitor S3307 was significantly higher than the control at 14:00-16:00.3.After exogenous GA₃ treatment,the activities and gene expressions of the key enzymes Rubisco,FBPase,GAPDH and FBA in the Karvin cycle process of the leaves and petioles were significantly lower than those of the control.At the same time,the photosynthetic parameters Pn,Gs,Tr of the leaves were significantly lower than the control from 12:00 to 18:00,and the change of Ci was opposite to Pn,Gs and Tr.The chlorophyll fluorescence parameters Fm,Fv/Fm,ETR decreased to varying degrees,and NPQ was significantly higher than the control.The inhibitor S3307 has the opposite effect to GA₃.It shows that the inhibitory effect of GA₃ on the phototropic rotation of leaves is related to its negative regulation of photosynthesis-related regulatory genes,weakening the photosynthetic capacity of leaves and petioles,and reducing the accumulation of photosynthetic products.4.After exogenous GA₃ treatment,the expression of Vv GAI1,Vv RGA,Vv SLR1and Vv GID1A,the key protein genes in GA signal transduction pathway,were decreased in leaves and petioles,and the contents of GA₃,IAA and ZT and the ratio of GA₃/IAA in leaves and petioles were increased.It reduced the content of ABA.It can be seen that the inhibitory effect of GA₃ on the phototropic rotation of leaves is related to the regulation of endogenous hormone content and the improvement of the ratio of GA₃/IAA in leaves and petioles.To sum up,exogenous GA₃ reduces the photosynthesis and accumulation of photosynthetic products of leaves and petioles,increases the ratio of endogenous GA₃to IAA,and thus has a certain inhibitory effect on the phototropic rotation of leaves.更多还原