【作者】 刘娜；

【导师】 郑云普；

【作者基本信息】 河北工程大学 ， 农业水土工程， 2021， 硕士

【摘要】 十九世纪工业革命以来,大气中温室气体(CO_2、N₂O、CH₄等)的浓度快速增加,尤其是全球二氧化碳浓度（[CO₂]）明显从工业革命前的280μmol mol^-1上升到400μmol mol^-1,甚至将在本世纪末上升至730～1000μmol mol^-1,这些变化主要归因于人类活动,例如燃烧大量矿物燃料、砍伐原始森林和改变土地利用方式等。我国以农业用水为主,但水资源供不应求,因此,利用水分调控机制提高土壤水分利用率对节约水资源具有重要意义。相比之前,[CO₂]倍增或不同水分亏缺条件对冬小麦的影响的研究均已较为成熟,但是对其多因素综合分析和各因素间相关关系分析的研究较少。本研究在可以精确控制[CO₂]的大型人工培养箱内模拟大气[CO₂]升高,设置2个不同的[CO₂],即400μmol mol^-1（a[CO₂]）和800μmol mol^-1（e[CO₂]）,并在不同水分亏缺条件下盆栽冬小麦,探讨水分对冬小麦的调控机制以及冬小麦气孔特性、光合性能和水分利用效率（WUE）对大气[CO₂]增加的响应,本研究得出的结论如下:（1）充分灌水条件下[CO₂]倍增使得冬小麦叶片近轴面气孔开度和气孔密度与对照组相比均显著增加,而对远轴面气孔并未产生显著影响。然而,水分亏缺降低冬小麦叶片远轴面和近轴面的气孔密度以及气孔开度,增加[CO₂]并没有产生缓解作用。另外,轻度亏水导致冬小麦叶片的气孔密度显著升高。（2）充分灌水条件时[CO₂]升高使得冬小麦叶片近轴面的气孔空间分布格局更加规则。而轻度亏水时[CO₂]增加导致冬小麦叶片远近轴面气孔在较小空间尺度范围的空间分布格局表现为规则分布。（3）水分亏缺显著降低冬小麦叶片净光合速率。在轻度亏水时,[CO₂]升高使净光合速率增加,但未达到显著水平,而在中度亏水和重度亏水时,净光合速率却降低。此外,冬小麦叶片WUE随着土壤含水量的减少而降低,而提高[CO₂],并没有阻止冬小麦叶片WUE的降低。（4）充分灌溉、轻度亏水和中度亏水条件下,提高[CO₂]使得冬小麦根系可溶性糖含量以及总非结构性碳含量均显著降低,而在重度亏水时提高[CO₂]增加了冬小麦根系可溶性糖和总非结构性碳含量。充分灌溉条件下,[CO₂]升高显著降低淀粉含量。而在水分亏缺条件下,[CO₂]倍增导致冬小麦叶片的蔗糖含量、可溶性糖含量和非结构性碳含量均增加。另外,在不同水分亏缺条件下,提高[CO₂]增加了冬小麦组织碳含量和氮含量,同时增加了冬小麦根系的碳氮比,而导致叶片的碳氮比降低。（5）不同水分亏缺条件下,提高[CO₂]使冬小麦叶绿素含量增加。而且在轻度亏水和重度亏水时分别显著提高40.8%和69.3%,表明[CO₂]升高可以缓解水分胁迫对冬小麦叶绿素含量的影响。此外,在充分灌溉条件下e[CO₂]使冬小麦地上生物量、地下生物量和总生物量分别显著提高33.8%、99.5%和48.0%,而轻度亏水时[CO₂]升高使冬小麦地下生物量增加,中度亏水时提高[CO₂]导致地上生物量增加。（6）冬小麦叶片远近轴面气孔密度均与WUE呈正相关关系。同时,冬小麦叶片净光合速率在远近轴面均随着气孔长度和气孔周长的增加而线性增加,却随着近轴面气孔形状指数的增加线性减小。另外,叶片近轴面气孔密度与叶片净光合速率的线性相关性较远轴面更高。此外,叶片净光合速率与气孔导度、总生物量及WUE呈正相关关系,但是与非结构性碳含量呈负相关关系。更多还原

【Abstract】 Since the Industrial Revolution in the 19th century,the concentration of greenhouse gases（CO₂,N₂O,CH₄,etc）in the atmosphere has increased rapidly,especially the global atmospheric CO₂ concentration（[CO₂]）levels have significantly increased from the industrial revolution of 280μmol mol^-1 to the present level of nearly 400μmol mol^-1,and may even reach about 730～1000μmol mol^-1 at the end of this century.These changes are mainly due to a series of human activities such as the burning large amounts of fossil fuels,cutting down primary forests,and changing land use methods.However,our country relies mainly on agriculture water,but the water resources are in short supply.Therefore,the use of water control mechanisms to improve soil WUE is of great significance to saving water resources.In the past,studies on the effects of CO₂ concentration doubling or different water deficit conditions on winter wheat have been relatively mature,but there are few comprehensive analysis of its multiple factors and the analysis of the correlation between the factors.However,due to the diversity of climate change,the environmental fators are complicated,so we should focus on the influence of multi-factor interaction on the surface stomatal characteristics,photosynthetic performance and WUE of winter wheat leaves.The experiment was conducted in each of eight identical controlled growth chambers,which in full irrigation and regulated deficit irrigation on the basis of the set of two different CO₂ concentration(400μmol mol^-1 and 800μmol mol^-1)to the cultivation of winter wheat under different water deficit conditions to investigate the response of leaf structure,physiological and biochemical processes and WUE of winter wheat to atmospheric CO₂ concentration rise under different water conditions.This study draws the following conclusions:（1）The stomata density of winter wheat leaves increased significantly when the slight water deficit.The carbon dioxide concentration doubled when fully irrigated,significantly increasing the stomata opening and stomata density on the paraxial surface of winter wheat.However,the stomata density and stomata opening of the abaxial and adaxial surfaces of winter wheat show a decreasing trend by improved CO₂concentration under the deficient water.（2）The combined increase of CO₂ concentration makes the spatial distribution pattern of stomatal space in the adaxial side of winter wheat leaves more regular under the condition of full irrigation.However,increasing the concentration of CO₂ results in a more regular distribution of stomata on the abaxial and abaxial surfaces of the blade in a smaller spatial scale under the slight water deficit.（3）The near photosynthetic rate of winter wheat decreased significantly under water deficit.In mild water deficit,the increase in CO₂ concentration increases the net photosynthetic rate,however,it does not reach a significant level.Increasing the concentration of CO₂ leads to a decrease in the net photosynthetic rate under moderate water deficit and severe water deficit.Moreover,the leaf water use efficiency decreased with the increase of water deficit,while the increase of CO₂ concentration did not improve the WUE of winter wheat leaves.（4）Fully irrigated under mild and moderate water deficit conditions,high CO₂concentration significantly reduced winter wheat root soluble sugar concentration and total non-structural carbon content,while increasing CO₂ concentration during severe water deficit increased winter wheat root soluble sugar and Total non-structural carbon content.Under the condition of full irrigation,the concentration of CO₂ increases,which significantly reduces the starch content.Under water deficit conditions,the doubled CO₂ concentration caused the sucrose concentration,soluble sugar content and non-structural carbon content of winter wheat leaves to increase.In addition,under different water conditions,increasing the concentration of CO₂ increased the C%and N%of winter wheat tissues,and at the same time increased the C/N of the winter wheat root system,resulting in a decrease in the C/N of winter wheat leaves.（5）Under different water conditions,the chloroplast content increased the chlorophyll content of winter wheat by increasing the CO₂ concentration.Moreover,it significantly increased by 40.8%and 69.3%in mild and severe water deficits,respectively.It shows that e[CO₂]can alleviate the effect of water stress on the chlorophyll content of winter wheat.In addition,e[CO₂]significantly increased the aboveground biomass,underground biomass,and total biomass of winter wheat by33.8%,99.5%,and 48.0%under sufficient irrigation conditions,while the increase in CO₂ concentration increased the underground biomass of winter wheat under mild water deficit.When the water deficit is moderate,increasing the concentration of CO₂leads to an increase in above-ground biomass.（6）The stomata densities on the abaxial and adaxial surfaces are positively correlated with WUE.At the same time,leaf photosynthesis increased linearly with the increase of stomata length and stomata circumference on both the abaxial and adaxial surfaces.The increase of the stomatal shape index near the seed surface resulted in a linear decrease in leaf photosynthesis.In addition,the linear correlation between the stomata density on the paraxial plane and the net photosynthetic rate of leaves is higher than that on the far axis plane.In addition,the net photosynthetic rate of leaves is positively correlated with stomatal conductance,total biomass and WUE.But there is a negative correlation with non-structural carbon content.更多还原