【作者】 刘瑞娜；

【导师】 郑有飞；

【作者基本信息】 南京信息工程大学 ， 环境科学， 2011， 硕士

【摘要】 近年来,南京地区及长江三角洲地区的NOX等臭氧前体物浓度迅速上升,导致地表03浓度不断增加,其对农作物等地表植物的影响已受到普遍关注,同时,广泛研究表明地表UV-B辐射对于地表生物有严重的胁迫效应。开展UV-B辐射和03浓度复合胁迫对作物生长和产量的影响研究,对于进一步探明逆境条件下农作物的响应机制具有重要的科学意义。本论文以冬小麦为受试作物,基于开顶式气室(OTCs),设置了UV-B增强10%(EUl)、UV-B增强20%(EU2)、100nL·L-103(E01)、150 nL·L-103(E02)、UV-B增强10%与100nL·L-103复合(EU1+EO1)、UV-B增强20%与100 nL·L-103复合(EU2+E01)、UV-B增强10%与150 nL·L103复合(EU1+E02)、UV-B增强20%与100 nL·L-103复合(EU2+E01)8个处理组,开展了UV-B辐射增强和03浓度增加对冬小麦生长和产量的影响及其模拟研究。主要结果如下：(1)孕穗期-杨花期UV-B和03复合作用对冬小麦叶面积指数的影响表现为协同作用,但灌浆期和成熟期叶面积指数高于单因子处理组。杨花期-成熟期03熏气在一定程度上缓解了UV-B对冬小麦单株叶片数和单叶叶面积的不利影响。复合作用对株高和节点数没有明显的效应。灌浆期-成熟期倒一节长介于EO1和EU2组之间。杨花期-成熟期倒二节长度为EU2>E01>CK>EU2+EO1。UV-B辐射增强在一定程度上能够缓解03对冬小麦茎粗的负作用。EU2、EO1、EU2+E01形态响应指数分别为49.4%、32.87%、33.25%。上述表明,复合作用对冬小麦形态特征的影响并不是单独作用的简单叠加。(2)UV-B和03复合胁迫下叶绿素含量显著下降；丙二醛和类黄酮含量显著增加,干物质量显著下降,且杨花期之后变化幅度均大于EU2和E01组。灌浆期-成熟期,复合胁迫组叶分配指数最高,穗壳分配指数显著下降,且下降幅度大于EU2和EO1组。灌浆后期籽粒分配指数介于E01和EU2组之间。EU2组旗叶转运率显著下降35.01%P<0.01),EO1组茎鞘转运率增加了7.63%(P<0.05),复合胁迫下旗叶可溶性糖含量和茎的转运率显著下降(55.61%),导致成熟期穗粒数和千粒重显著下降,且下降幅度大于单因子处理组。EU2、E01、EU2+EO1冬小麦产量分别下降了31.54%(P<0.05)、23.64%(P<0.05)、40.72%(P<0.01)。以上结果表明,灌浆期-成熟期是UV-B和03复合胁迫对冬小麦生长产量影响的敏感时期,冬小麦不同的生长生理指标对UV-B和03复合胁迫表现出不同的相互作用。(3)基于大田试验,在Vensim PLE系统动力学软件下,通过引入UV-B和03对冬小麦最大光合速率和叶面积指数的影响的胁迫系数(fc1,fc2),建立了模拟冬小麦干物质累积和产量形成的系统动力学模型。模拟结果表明,总干重、地上总干重和产量模拟值与实测值相关性达到了显著性水平(P<0.01),总干重、地上总干重和籽粒重量的模拟值与实测值的相对误差分别为9.05%、10.01%、16.19%。表明,在灌浆后期UV-B和03复合胁迫对干物质生产和生物产量以及籽粒产量存在协同作用。更多还原

【Abstract】 Emissions of ozone (O3) precursors of methane and NOx due to human activity and fossil-fuel combustion leaded to an increase in ground-level O3 in Yangtze River Delta, China, At present, the adverse effects of O3 on wheat have been reported extensively. Meanwhile The extensive research showed that UV-B radiation (UV-B:280-320 nm) is also a menace to many crops. The study on the influencing mechanism and influence degree of the compound stress on winter wheat is of profound theoretical and practical significance. In this study, with open-top chambers established in the field in Nanjing we investigated the responses of winter wheat to elevated UV-B and O3 levels at different growth stages, and analyzed yield components at harvest time. This study provides the first-hand field observations for studying the compound effects of two important environmental factors (UV-B and O3) that are projected to change in the future climate on winter wheat growth and development. The experimental design consisted of eight treatments:CK (the control, natural solar UV-B irradiance, ambient air with approximately 50nl·L-1O3), EU1(10% higher level of UV-B intensity, ambient air with approximately 50 nl·L-1 O3),EU2(20% higher level of UV-B intensity, ambient air with approximately 50 nl·L-1O3), EO1(natural solar UV-B irradiance, mixed gas with approximately 100 nl·L-1 O3), EO2(natural solar UV-B irradiance, mixed gas with approximately 150 nl·L-1O3),EU1+EO1(10% higher level of UV-B intensity, mixed gas with approximately 100 nl·L-1O3), EU2+EO1(20% higher level of UV-B intensity, mixed gas with approximately 100 nl-L-1O3), EUl+EO2(10% higher level of UV-B intensity, mixed gas with approximately 150 nl-L-1O3). The main conclusions of this paper were as follows:(1)From booting stage to blooming stage, the interactive stress of UV-B and O3 significantly decreased leaf area index, with the reductions larger than those under single stress, however, in filling and ripening stage, the leaf area index under compound stress was lager than that under single stress. From blooming to ripening and the compound effects of UV-B and O3 on leaf number per plant and leaf area per leaf can be explained as antagonistic action. There was no significant difference in the plant height and internode number. In filling and ripening the topmost knop length under compound stress was between those under EU and EO. The compound effects of UV-B and O3 can alleviate the adverse effects of O3 to stem diameter of winter wheat. Compared to the contral, the morpha response index under 20% higher level of UV-B intensity, mixed gas with approximately 100 nl·L-1 O3 and the compound stress is 49.4%,32.87%,33.25% respectively. The compound effects of UV-B and O3 on morphological character of winter wheat were not simple additive relation.(2) Under the interactive stress of ultraviolet-B and O3, the content of chlorophyll decreased very significantly, and the reductions had no significant difference with that under the single stress of UV-B. Malonaldehyde and flavonoids increased markedly with the increment larger than those under single stress after blooming. Dry matter weight decreased significantly with the decrements larger than that under any single stress in filling and ripening; The partitioning index of leaves was higher than that under other treatments in filling and ripening; The partitioning index of stalk decreased significantly with the decreament larger than that single stress; The partitioning index of grains was higher than that under ultraviolet-B treatment and lower than that under O3 treatment in later filling stage; However, no significant difference was detected in the partitioning index of stem. Under EU2 condition, the contribution of leaves was dcreased by 35.01%(P<0.01), however, under the EOl condition, the contribution of stalk wase increased by 7.63%(P<0.01). Under the compound stress, the average content of soluble sugar in the flag leaf and contribution of stem decreased significantly, which leaded to significant declines in both grains per panicle and 1000-grains weight. Compared to the contral, the yield of winter wheat under 20% higher level of UV-B intensity, mixed gas with approximately 100nl·L-1 O3 and the compound stress is reduced by 31.54%(P<0.05),23.64%(P<0.05),40.72%(P<0.01) respectinely. The above results showed that the filling-ripening stage is the sensitive developmental period of winter wheat under the compound stress.Different indicators for growth and physiology of winter wheat exhibited different compound effects in response to the interactive stresses of ultraviolet-B and O3.(3) A dynamic model is established in this study and runs under a Vensim PLE software. Indices (fc1, fc2) were built in the model to explore how the plant response to the stresses. Additionally, the correlation between the stress factors for UV-B intensity and O3 concentration and the increase rate of the fraction of grain weight was established to simulate the yield formation. The model was examined via experimental document. Results showed that the model has good performances on predicting the dynamic formation of total dry matter, aboveground dry matter and yield of winter wheat. The correlation coefficients between observed value and simulated value were significant (P<0.01). The relative errors (RE) for total dry matter, aboveground dry matter and grain weight were 9.05%,10.01%,16.19%, respectively. The model demonstrated that elevated UV-B and O3 has synergistic impacts on dry matter production, biological yield and yield formation in later filling stage of winter wheat.更多还原