【作者】 周文鳞；

【导师】 娄运生；

【作者基本信息】 南京信息工程大学 ， 应用气象学， 2013， 博士

【摘要】 水稻是主要粮食作物之一,为全球近一半人口提供粮食。中波紫外辐射(UV-B)增强对水稻的影响广受关注；人口的增加和耕地面积的减少是影响粮食安全的主要矛盾,增施化肥是提高粮食产量的重要措施。本研究通过大田试验、盆栽试验及室内分析等方法,研究了UV-B增强和控释氮肥对抗除草剂转基因水稻生长及产量、光合特性、甲烷排放和水稻土甲烷产生潜力等方面的影响。开展本研究对于进一步完善转基因水稻生态风险评价的内容、指标和体系等方面具有重要的理论和实践意义。主要研究结果如下：(1)水稻生长及产量UV-B增强抑制了转基因水稻及其亲本常规水稻叶面积、分蘖数、株高、地上部和地下部生物量,最终造成水稻产量及其构成因素(主穗长、有效穗数、实粒数、结实率、千粒重等)的下降。控释氮肥处理的水稻叶面积和株高,于孕穗期前低于尿素分施处理,而孕穗期后逐渐接近。控释氮肥处理的水稻分蘖数于分蘖末期前少于尿素分施处理,分蘖末期后肥料处理间差距缩小。控释氮肥可促进水稻地上部、地下部生物量,从而促进水稻产量及其构成因素(有效穗数、实粒数、千粒重等)的增长。(2)水稻光合生理特性与对照相比,在分蘖期、扬花期及完熟期,UV-B增强抑制了转基因水稻及其亲本水稻剑叶的饱和光强净光合速率、蒸腾速率和单叶水分利用率；抑制了扬花期两种水稻剑叶的气孔导度。UV-B增强抑制了转基因及其亲本水稻分蘖期、扬花期及完熟期内剑叶净光合速率、气孔导度、蒸腾速率和单叶水分利用率的日变化以及分蘖期它们对光合有效辐射的响应。非直角双曲线Farquhar模型模拟的光合参数显示,在分蘖期,UV-B增强抑制了两种水稻的最大净光合速率(Pnmax)、暗呼吸速率(Rd)、光合补偿点(LCP)和光合饱和点(LSP)。与尿素相比,在分蘖期、扬花期及完熟期,控释氮肥提高了转基因及其亲本水稻剑叶饱和光强净光合速率、蒸腾速率和单叶水分利用率：提高了扬花期水稻剑叶的气孔导度。控释氮肥提高了转基因及其亲本水稻分蘖期、扬花期及完熟期内剑叶净光合速率、气孔导度、蒸腾速率和水分利用率的日变化以及分蘖期、完熟期它们对光合有效辐射的响应。非直角双曲线Farquhar模型模拟的光合参数显示,分蘖期控释氮肥促进了转基因水稻的Pnmax、Rd和LCP,促进了亲本水稻的Rd和LCP。完熟期控释氮肥促进了转基因及其亲本常规水稻的Pnmax、Rd、LCP和LSP。(3)水稻土甲烷排放UV-B增强对稻田CH4排放通量的季节性变化趋势没有影响。与对照相比,UV-B增强显著提高CH4排放通量、累积排放量(p<0.05)以及CH4排放通量日变化趋势(p>0.05)。与尿素相比,控释氮肥可显著降低CH4排放通量、全生育期累积排放量(p<0.05)以及CH4排放通量日变化趋势(p<0.05)。抗除草剂转基因水稻的CH4排放通量和累积排放量均显著低于亲本常规水稻(p<0.05)。(4)水稻土甲烷产生潜力UV-B增强明显提高水稻扬花期和完熟期内的根际与非根际水稻土的CH4产生潜力(p>0.05),控释氮肥则是抑制作用(p>0.05)。亲本常规水稻两个生育期内的根际与非根际水稻土CH4产生潜力高于转基因水稻。水稻根际土壤CH4产生潜力大于非根际。(5)水稻根系残体分解在相同水分条件下,CH4和C02的排放通量均表现为转基因水稻高于常规水稻。施用稻根可明显提高CH4和CO2的排放通量。在添加同种根系残体下,CH4排放总量呈现为好气明显低于淹水,而C02排放通量则相反。好气条件下,培养后期CH4排放通量与气温呈显著负相关。淹水条件下,在整个培养期内,无论添加何种根系残体,CH4排放通量与气温均呈显著正相关。淹水条件下,CH4排放通量与土壤微生物量碳呈显著正相关。更多还原

【Abstract】 Rice is one of the predominant staple foods in the world, which feeds over50%of the worldwide population for about80%of their food requirements. So far, the effect of elevated UV-B radiation on rice production has received more attentions. Population explosion and limited arable soils are threatening food supply security. Field and pot experiment with rice cultivars were conducted to investigate the effects of elevated UV-B radiation and controlled-release nitrogen fertilizer (CRNF) on the growth characteristics, photo synthetic characteristics, CH4emission, CH4production potentials and so on. This study will be helpful in further improving ecological risk assessment on transgenic rice.Main results are as follows:(1) Rice growth characteristics:Elevated UV-B radiation inhibited rice single leaf area, till numbers, plant height, above and underground biomass, finally decreased rice production and component factors (i.e. main panicle length, effective panicles, filled grains, productive panicle rate,1000-grain weight and so on).Single leaf area and plant height were higher under urea treatment than CRNF treatment until booting stage, and then the difference between two fertilizer treatments gradually diminished. Tiller numbers between before and after late-tillering stage came to the similar conclusion. Application of CRNF finally increased above and underground biomass, rice production and component factors (i.e. effective panicles, filled grains,1000-grain weight and so on).(2) Rice photosynthetic characteristics:Elevated UV-B radiation decreased the net photosynthetic rate (Pn), transpiration rate (Tr), water use efficiency (WUE) of two cultivars at tillering, blooming and mature stage, stomata conductance (Gs) at blooming stage under saturation light. In addition, elevated UV-B radiation decreased the diurnal variation of Pn, Tr, Gs and WUE at above three stages and Pn, Tr, Gs and WUE to photosynthetic active radiation at tillering stage. Farquhar models showed that maximum apparent photosynthesis rate (Pnmax)、dark respiration rate (Rd)、light compensation point (LCP) and light saturation point (LSP) of two culivars were inhibited by elevated UV-B radiation at tillering stage.CRNF increased Pn, Tr, WUE of two rice cultivars at tillering, blooming and mature stage, Gs at blooming stage under saturation light. In addition, diurnal variation of Pn, Tr, Gs and WUE at above three stages and Pn, Tr, Gs and WUE to photosynthetic active radiation at tillering and mature stage were improved by CRNF application. Farquhar models showed that CRNF increased Pnmax、Rd and LCP of transgenic rice, Rd and LCP of parent rice at tillering stage and Pnmax、Rd、LCP and LSP of two cultivars at mature stage.(3) CH4emission in rice:Elevated UV-B radiation had no effect on seasonal dynamics of CH4flux in paddy field. Compared with control, elevated UV-B radiation increased CH4flux and total amount of CH4emission (p<0.05) and CH4diurnal variation (p>0.05).Compared with control (urea), one-time basal application of CRNF decreased CH4emission (p<0.05) and CH4diurnal variation (p<0.05) in the paddy soil.Regardless of UV-B radiation and fertilizer treatments, CH4flux and total amount of CH4emission were higher in parent rice than transgenic rice.(4) Methane production potentials in rhizosphere and non-rhizosphere paddy soil:Elevated UV-B radiation increased methane production potentials in rhizosphere and non-rhizosphere soils(p>0.05), while CRNF decreased them(p>0.05)at blooming and mature stage. Regardless of UV-B radiation and fertilizer treatments, methane production potentials in rhizosphere and non-rhizosphere from parent rice paddy soils were higher than from transgenic rice. Methane production potentials in rhizosphere soil were larger than non-rhizosphere soil.(5) Rice root residues decomposition:The fluxes of CH4and CO2were higher in the soil amended with transgenic rice root residues than those with conventional parental root residues. Compared with the control, the fluxes of CH4and CO2were obviously increased by amending rice root residues. The CH4fluxes were lower in the aerobic treatments than in the flooding treatments, but opposite for CO2fluxes. A significant correlation was found between CH4fluxes and soil temperatures, negatively under aerobic conditions at the later stage and positively under flooding condition. The CH4fluxes were significantly correlated with the amounts of microbial biomass C under flooding condition, regardless of the type of rice root residues amended.更多还原