【作者】 麦博儒；

【导师】 郑有飞； 李占清；

【作者基本信息】 南京信息工程大学 ， 大气物理学与大气环境， 2011， 博士

【摘要】 当前,太阳辐射减弱所引起环境效应受到了人们的广泛关注。近年来,中国地区大气气溶胶的浓度、大气浑浊度及灰霾日数增加导致到达地表的太阳辐射呈现降低趋势,其中长江三角洲地区的降低较明显。本研究通过大田试验及模型模拟方法系统研究了太阳辐射减弱对冬小麦生长发育、光合生理特性、干物质累积及分配、产量的影响,建立、修订光合作用及干物质生产模型。通过作物模式分析了辐射减弱条件下农作物干物质的累积和分配特征,提出了模式的改进措施,为全面准确评估气候变化对我国主要粮食作物产量的影响提供依据。主要结果如下：(1)在太阳辐射减弱条件下,冬小麦叶绿素(Ch1)、类胡萝卜素(Car.)和叶黄素(Xanthophy)的含量明显上升,增强了作物对光能的吸收和利用能力。从拔节期至成熟期,60%-40%自然光处理降低了叶片净光合速率(Pn)、气孔导度(Gs)、蒸腾速率(Tr)、水分利用率(WUE)和气孔导度限制值(Ls),增加了胞间二氧化碳浓度(Ls)。在同样的辐射减弱条件下,上述变量对光强的敏感度明显受到抑制。太阳辐射减弱条件下,冬小麦叶片光合系统未发生光抑制或光破坏,因此其最大量子效率和初始荧光上升。辐射减弱显著抑制光合系统Ⅱ(PSII)反应中心的吸收与利用光能的能力、光化学猝灭系数(qP)及叶片的电子递体(PQ)的活性,增加了PSII吸收的光能向热耗散途径分配的比例。60%-40%自然光处理显著增强冬小麦叶片的过氧化物酶(POD)、超氧化歧化酶(SOD)活性,提高丙二醛(MDA)和电导率(EC)的含量,有效清除了自由基对质膜系统的伤害。太阳辐射减弱降低叶片可溶性糖、可溶性蛋白质的含量,但促进总游离氨基酸的累积。(2)60%-20%自然光条件下,冬小麦增加株高(PH)和叶面积(LA),降低单位叶重(LMA)、根干物质比(RMR)、茎干物质比(SMR)和根冠比(LCR),提高叶干物质比(LMR)、叶重分数(LMF)、叶面积比(LAR)和叶面积-根干物重比(LARMR)。上述调整一定程度上提高了光能的获取和利用能力,但不足以弥补光能不足所带来的影响,因此总生物量(TB)净同化率(NAR)和相对生长率(RGR)持续下降。(3)修订的WheatGrow(WG)模型能较好地反映太阳辐射减弱条件下冬小麦光合作用和干物质生产的变化。在水肥充足条件下60%、40%自然光处理的冬小麦光合作用和总干物质质量分别下降了23%、31%,35%、41%,籽粒产量下降了34.08%和47.91%。在极端情况下,20%和15%自然光处理的冬小麦光合速率、总干物重及籽粒产量分别下降了46%和48%,56%和57%,88.31和87.40%。(4)CERES-Wheat模型一定程度上能反映太阳辐射减弱对冬小麦干物质的累积的影响,但未能反映干物质在不同器官中的分配特征。60%-15%自然光条件下,冬小麦总生物量下降了37.61%-71.69,根、茎和叶生物量分别下降了46.49%-57.30%、21.7-76.76%和51.8%-66.2%。更多还原

【Abstract】 The solar irradiance and its environmental impacts are growing concerns worldwide. In the recent years, the aerosol loading, atmospheric turbidity and haze day over china area increase considerably, resulting in decrease in the surface shortwave radiation and the reduction in Yangtze delta is more obvious. On this study, the reduced solar irradiance on the growth, photosynthetic characteristics, biomass production and yield of winter wheat were investigated via field experiments and model simulation. Further more, the dry matter accumulation and distribution characteristics of this cultivar were elucidated by means of CERES-Wheat model. Results are as follows:(1) Under reduced solar irradiance condition, the contents of chlorophyll (Chla, Chlb, Chl(a+b)), carotenoid and xanthophyll in winter wheat leaves increase significantly, which can improve the plant’s ability for light absorption and utilization. Irradiance of 60%-20% incident solar light significantly decreased the net photosynthetic rate(Pn), stomata conductance(Gs), transpiration rate(Tr), water use efficience(WUE) and stomatal limitation(Ls), but increased the intercellular CO2 concentration(Ci), and the sensitivity to light of the above parameters was also restrained. Photoinhibition or photo-damage to the PSII didn’t occur when the plants were subjected to 60%-20% incident solar irradiance, thus the maximum quantum yield of PSII(Fv/Fm) and the initial fluorescence(Fo) increased substantially. The effective quantum yield of PSII(Yield), maximum photosynthesis(Pm) and photochemical quenching(qP) were restricted under reduced solar irradiance condition, while the non-photochemical quenching(NPQ) increased significantly, demonstrating that more excess of light energy in PSII was dissipated through heat dissipation. The contents of peroxidase(POD), superoxide dismutase (SOD), malonaldehyde(MDA) and electrolyte leakage(EC) increased pronouncedly in response to 60%-20%incident solar irradiance treatments, thus the plants could effectively eliminate the attack of active oxygen species (AOS) to cell membrane, preventing peroxidation damage caused by reduced solar light. The solar irradiance intensity lower than 60% incident solar light significantly decreased the contents of soluble sugar and soluble protein, while increased the total free amino acid content in leaves of winter wheat.(2)Under long term negative effects of 60%-20% incident solar light, the plant height(PH), leaf area(LA), leaf mass ratio(LMR),leaf mass fraction(LMF),leaf area ratio(LAR) and leaf area-root mass ratio(LARMR) of winter wheat increased significantly, on the contrary, the leaf mass per unit area(LMA), root mass ratio(RMR), stem mass ratio(SMR) and root crown ratio(RCR) presented a trend of increase. This strategy of biomass distribution could enhance the ability of light capture and light use efficiency to a certain extern, but could not off set the negative impact of insurfficient light, thus the total biomass(TB), net simulation rate(NAR) and relative growth rate(RGR) decreased substantially.(3) The revised WheatGrow(WG) model has good preferment on predicting photosynthesis and biomass assimilation of winter wheat. Solar irradiance of 60% and 40% incident solar light could respectively resulted in significant reduction of 23% and 31% in photosynthetic rate of winter wheat,35% and 41% for total biomass and 34.08% and 47.91% in grain yield. When the solar irradiance decreased to 20% and 15% incident solar light, thepho to synthetic rate declined by 46% and 48%, total biomass decreased by 56% and 57%, and reduction of grain yield was 88.31% and 87.40%, respectively.(4) The CERES-Wheat has certain of ability to assess the biomass accumulation of winter wheat, but can not well simulate the distribution of biomass among organs under reduced solar irradiance condition..When solar irradiance decreased to 60%-15% of incident solar light, the total biomass decreased by 37.61%-71.69%, and the root, stem and leaf biomass declined by 46.49%-57.30%,21.7%-76.76% and 51.8%-66.2%,respectively.更多还原