【作者】 武永胜；

【导师】 龚月桦；

【作者基本信息】 西北农林科技大学 ， 植物学， 2009， 硕士

【摘要】 本试验于2007～2008年在西北农林科技大学生命科学学院防雨蓬中进行,选用4个冬小麦品种小偃22号(XY22)、温麦6号(WM6)、豫麦66号(YM66)、潍麦8号(WM8),研究了不同水分处理下小麦的持绿特性和抗旱性的关系。根据以前的研究,WM6为早衰型品种;XY22为正常品种;WM8、YM66为持绿型小麦品种。实验设正常供水处理,中度干旱和严重干旱三个处理。研究了花后不同干旱处理对持绿型小麦叶片衰老、光合功能、根系特征、物质生产的影响,主要结果如下:1、不同冬小麦品种间,持绿型小麦品种的绿叶面积、光合色素含量在整个灌浆期都大于非持绿型小麦品种;而丙二醛含量在整个灌浆期都小于麦非持绿型小麦品种。在不同干旱胁迫下随着生育进程的推进绿叶面积、光合色素含量的下降幅度和丙二醛含量的上升幅度都表现为严重干旱>正常供水>中度干旱,但与非持绿型小麦相比,持绿型小麦不论是上升指标的幅度还是下降指标的幅度都相对较小。持绿型小麦品种膜脂过氧化程度较低,抗氧化酶活性相对较高,叶片功能期较长。2、四个冬小麦品种的旗叶净光合速率在整个灌浆期表现先升后降的趋势,在花后7d达最大值,在灌浆后期持绿型小麦品种维持较高的光合速率,光合速率高值持续时间长。在不同干旱处理下光合速率的大小表现为中度干旱>正常供水>严重干旱,严重干旱下小麦叶片的光合速率大大降低。但与非持绿型小麦相比,持绿型小麦在各个处理下光合速率降低的幅度都相对较小。3、四个冬小麦品种在灌浆期的荧光参数变化表明,随着生育进程推进,Fv/Fm、Fv/Fo、qP、Yield、ETR都呈现降低的趋势,而且在严重干旱胁迫下前述指标也迅速下降;而qN却表现出增加的趋势;严重干旱胁迫使qN增加明显,表明在叶片衰老的后期和严重干旱胁迫下, PSⅡ的光化学效率和电子传递速率都有所降低,而热耗散加强。但持绿型小麦具有较高的PSⅡ的潜在活性和光化学效率,光能的捕获效率、光化学电子传递份额和电子传递效率的降低幅度在干旱处理下都相对较小,可见持绿型小麦后期光合机构保持完整,有较高的光合功能。4、不同冬小麦品种间,持绿型小麦叶片和茎秆贮存的干物质转移量、干物质转移率、贮存干物质对籽粒的贡献率都高于非持绿型小麦品种;在不同干旱处理下叶片和茎秆贮存的干物质转移量、干物质转移率、贮存干物质对籽粒的贡献率都表现为严重干旱>正常供水>中度干旱。茎秆贮存的干物质转移量、干物质转移率、贮存干物质对籽粒的贡献率都大于相对应的叶片。5、不同冬小麦品种叶片和茎秆的含水量都表现为正常供水>中度干旱>严重干旱,持绿型小麦叶片和茎秆在不同水分处理下有相对较高的含水量,充分延缓了叶片的衰老,可能是由于持绿型小麦品种吸水能力较强或者保水能力强6、不同冬小麦品种在严重干旱胁迫下根数量、长度、体积、干重以及根冠比都下降,中度干旱变化不明显,持绿型小麦在不同水分处理下都具有较多的根数量和较大的根长度、体积、干重和根冠比,因而具有较好的抗旱能力。7、不同冬小麦品种在严重干旱胁迫下穗重、穗粒数、千粒重、籽粒产量和总生物量都下降,中度干旱变化不明显。持绿型小麦在不同干旱处理下穗重、穗粒数、千粒重、籽粒产量和总生物量都相对较高,因此具有较高的增产能力。更多还原

【Abstract】 In order to elucidate the relationship between the stay-green traits and resist to drought of winter wheat in different water conditions,four different winter wheat XY22、WM6、YM66、WM8 were studied in the field under a retractable awning in life-science department of Northwest A&F University in 2007-2008.According to the study before,WM6 belongs to premature senility variety,XY22 belongs to routine variety,YM66 and WM8 belongs to stay-green variety.The wheat were subjected to three levels of drought stress: normal -watered,midding-drought and severe drought.The effects of different drought level to the senescence of stay-green wheat leaves such as the photosynthetic function、roots character and substantial production under anthesis were studied,the results as follows:1.In different winter wheat varieties,The area of green leaves and the content of photosynthetic pigment of stay-green wheat are all higher than nonstay-green wheat in grain filling stage.But the MDA content are lower than nonstay-green wheat.As breeding processing,the decline extent of the area of green leaves and the photosynthetic pigment,and the ascend extend of MDA are all present as follows: severe drought>normal -watered>midding drought,But compared with nonstay-green wheat,either its ascend extend or its descend extend are all small.The stay-green wheat varieties maintained lower MDA content,the activities of antioxidative enzymes is relatives more higher,the functional stage is relatively longer.2.The Net photosynthetic rate(Pn)in flag leaves of four wheat varieties increased from flowering stage and reached their maximal Pn about 7 days after anthesis,and after that,declined gradually,the Pn of stay-green wheat maintain a higher level at late grain filling stages and persist a longer time.The Pn at different drought levels present as follows: midding drought > normal -watered > severe drought,the Pn at severe drought level descend significantly. But compared with nonstay-green wheat its Pn are all relatively smaller at different levels.3.The varieties of fluorescence parameter of different four winter wheat in grain filling stages show that, As breeding processing,Fv/Fm、Fv/Fo、qP、Yield、ETR are all present a declining trend, And they are decline significantly at the severe drought level.But ,qN present a increasing trend;qN increased significantly at the severe drought level.This indicate that the Yield、ETR present a descending trend,and the dissipation of heat increasing at late stage of senescence or severe drought.But,the PSⅡof stay-green wheat have a high Fv/Fo、Fv/Fm,the descend extent of Yield、qP、ETR are relatively small under drought stress,this indicate photosynthetic organ of the stay-green wheat maintain integrity and have a high photosynthe tic function.4.The dry matter transloction、dry matter transloction efficiency and the proportion of dry matter transloction in grain of leaves and stems of stay-green wheat are higher than nonstay-green wheat in different winter wheat; The dry matter transloction、dry matter transloction efficiency and the proportion of dry matter transloction in grain of leaves and stems at different drought stress present: severe drought>normal-watered>midding drought. The dry matter transloction、dry matter transloction efficiency and the proportion of dry matter transloction in grain of stems are higher than of leaves.5.The water content of leaves and stems of different winter wheat present as follows: normal-watered>midding drought >severe drought,the leaves and stems of stay-green wheat have a relatively high water content under different drought stress,delay senescence largely,this maybe results of high absorption ability and maintain water ability of stay-green wheat.6.The root number、length、volume、dry matter and root/shoot of different wheat are all descend under severe drought stress,but its not so evident under midding drought stress.The stay-green wheat have larger root number、longer root length、volume、dry matter and root/shoot,so it has a better resistant drought ability.7.The Ear weight、Kernels、Grain weight、Seed Yield、Total Biomass of different wheat are all descend under severe drought stress,but its not so evident under midding drought stress.The stay-green wheat have larger Ear weight、Kernels、Grain weight、Seed Yield、Total Biomass,so it has a better increase production ability.更多还原