花后轻干-湿交替灌溉提高水稻籽粒淀粉合成相关基因的表达

【目的】水稻籽粒灌浆是光合同化产物向籽粒运输并合成淀粉的生理过程,决定水稻结实率、粒重高低及品质优劣。籽粒灌浆过程不仅受遗传因素的影响,而且受到温度和水分等环境因子的调节。灌溉是水稻生产上一项重要的技术,对水稻产量的形成有重要调控作用。但有关花后灌溉方式对水稻籽粒淀粉合成相关基因表达的影响,缺乏研究。本研究旨在探讨花后干湿交替灌溉对水稻籽粒灌浆的影响并阐明其分子机理。【方法】2012-2013年以两优培九（两系杂交籼稻）和扬粳4038（杂交粳稻）为材料种植于土培池,自抽穗（50%穗伸出剑叶叶鞘）至成熟设置3种灌溉方式处理：（1）常规灌溉（conventional irrigation,CI）,保持浅水层,收获前一周断水;（2）轻干-湿交替灌溉（alternate wetting and moderate soil drying,WMD）,自浅水层自然落干至土壤水势达-20 kPa时,灌水1-2 cm,再自然落干至土壤水势为-20 kPa,再上浅层水,如此循环;（3）重干-湿交替灌溉（alternate wetting and severe soil drying,WSD）,自浅水层自然落干至土壤水势达-40 kPa时,灌水1-2 cm,再自然落干至土壤水势为-40 kPa,再上浅层水,如此循环。观察花后干湿交替灌溉对水稻强、弱势粒灌浆速率、粒重和淀粉合成相关酶活性的影响,并应用实时荧光定量PCR技术测定编码这些酶基因的相对表达量。【结果】强势粒的平均灌浆速率、粒重、淀粉合成有关的蔗糖合酶（SuS）、腺苷二磷酸葡萄糖焦磷酸化酶（AGP）、淀粉合酶（StS）和淀粉分支酶（SBE）等相关酶活性以及蔗糖合酶基因SuS2、SuS4,腺苷二磷酸葡萄糖焦磷酸化酶基因AGPL1、AGPL2、AGPL3、AGPS2,淀粉合酶基因SSI、SSIIa、SSIIc、SSIIIa和淀粉分支酶基因SBEI、SBEIIb的相对表达量在3种灌溉方式处理间没有显著差异。与常规灌溉相比,轻干-湿交替灌溉处理显著增加了弱势粒的平均灌浆速率、粒重、4种籽粒淀粉合成相关酶活性和除AGPL1外各基因的相对表达量,重干-湿交替灌溉处理则显著降低弱势粒的平均灌浆速率、粒重、各淀粉合成相关酶活性和基因的相对表达量。两供试品种试验结果趋势一致。相关分析表明,弱势粒的平均灌浆速率、粒重与SuS、AGP、StS、SBE活性以及SuS2、SuS4、AGPL2、AGPL3、AGPS2、SSI、SSIIa、SSIIc、SSIIIa、SBEI、SBEIIb基因的相对表达量呈极显著正相关关系。【结论】在轻干-湿交替灌溉处理下,水稻弱势粒淀粉合成相关酶活性及其基因表达的增强促进了弱势粒中淀粉的合成与积累,提高灌浆速率和增加粒重;而在重干-湿交替灌溉处理下,弱势粒中上述淀粉合成相关酶活性和基因表达的下降使其灌浆速率和粒重显著降低。     

Factors influencing activation of wet fly ash

To use fly ash, it is necessary to understand its activity variation under different wet conditions. Four low-calcium wet fly ash preparations are simulated in the laboratory. Fly ash activity is indicated by measuring specific compressive stre     

Design and optimization of drawing surface and FE analysis forthe front side panel of autobody

The drawing process of the front side panel of autobody is simulated by using the finite element software, Dynaform. The drawing surface is designed, focusing on the optimization of the addendum and the drawbead layout. By comparing the stress/strain conditions and the FLD in two types of addendum (stepped and slope) and three types of drawbead layout (closed, discontinuous and oblique drawbead), the slope addendum is chosen as the optimized addendum and the oblique drawbead is chosen as the optimized drawbead layout. The simulation results show the material flow in the corner and the quality of the part can be improved effectively with the optimized drawing surface. The optimized parameters are employed in production and acceptable quality parts are produced. Therefore, the optimized drawing surface is verified to be effective.     

压片式微喷带单孔水量分布特性试验研究

试验研究了不同工作压力(0.1MPa和0.15 MPa)、不同喷射角度(43°、65°和79°)和不同喷孔直径(0.5、0.6和0.7mm)对压片式微喷带水量分布的影响。试验结果表明,干燥区宽度、湿润区长度和湿润区面积主要受喷射角度影响,均随喷射角度的增大而减小;湿润区宽度相对稳定,但在0.15MPa下,随着喷孔直径的增大有明显的增加趋势;平均灌水强度随着喷射角度、喷孔直径和工作压力的增大均有增加趋势,其中喷射角度影响最为明显。     

沟灌条件下灌水沟入渗特性研究

为探明沟灌时灌水沟的水分入渗规律,从沟灌二维入渗过程、入渗湿润锋运移特性、累计入渗水量变化过程、土壤含水量分布等方面研究了沟灌的入渗特征及其影响,研究表明：灌水沟中水深、沟底宽、湿周对沟灌入渗过程均有明显影响。沟中水深增大,有利于加大侧向入渗,垂向入渗减少,而水深减小,会加大垂向入渗,增加深层渗漏。灌水沟底宽不影响灌水沟的侧向入渗,仅影响垂向入渗,底宽减小,垂向入渗深度相应减小,且土壤表面以下40 cm深以内水平向入渗深度平均值与最大垂向入渗深度的比值在沟底宽小时均大于沟底宽大时。合理的断面形式和大小有利于减小垂向入渗,加大水平侧向入渗,灌水沟断面形式为梯形断面时,宽深比近似为2效果最优。研究结果可为改进沟灌灌水技术提供参考。     

Evaluation and application of ORYZA2000 for irrigation scheduling of puddled transplanted rice in north west India

Water-saving technologies that increase water productivity of rice are urgently needed to help farmers to cope with irrigation water scarcity. This study tested the ability of the ORYZA2000 model to simulate the effects of water management on rice growth, yield, water productivity (WP), components of the water balance, and soil water dynamics in north-west India. The model performed well as indicated by good agreement between simulated and measured values of grain yield, biomass, LAI, water balance components and soil water tension, for irrigation thresholds ranging from continuous flooding (CF) to 70 kPa soil water tension.Using weather data for 40 different rice seasons (1970-2009) at Ludhiana in Punjab, India, the model predicted that there is always some yield penalty when moving from CF to alternate wetting and drying (AWD). With an irrigation threshold of 10 kPa, the average yield penalty was 0.8 t ha⁻¹ (9%) compared with CF, with 65% irrigation water saving, which increased to 79% at 70 kPa with a yield penalty of 25%. The irrigation water saving was primarily due to less drainage beyond the root zone with AWD compared to CF, with only a small reduction in evapotranspiration (ET) (mean 60 mm).There were tradeoffs between yield, irrigation amount and various measures of WP. While yield was maximum with CF, water productivity with respect to ET (WP_ET) was maximum (1.7 g kg⁻¹) for irrigation thresholds of 0 (CF) to 20 kPa, and irrigation water productivity (WP_I) increased to a maximum plateau (1.3 g kg⁻¹) at thresholds ≥30 kPa.Because of the possibility of plant stress at critical stages known to be sensitive to water deficit (panicle initiation (PI) and flowering (FL)), treatments with additional irrigations were superimposed for 2 weeks at one or both of these stages within the 10, 20 and 30 kPa AWD treatments. Ponding for two weeks at FL was more effective in reducing the yield penalty with AWD than ponding at PI, but the biggest improvement was with ponding at both stages. This reduced the average yield loss from 9% (0.8 t ha⁻¹) to 5% (0.5 t ha⁻¹) for AWD with thresholds of 10 and 20 kPa. However, maximum WP_I (1.1 g kg⁻¹) was achieved with an irrigation threshold of 20 kPa combined with more frequent irrigation at FL only, but with a greater yield penalty (8%). Thus the optimum irrigation schedule depends on whether the objective is to maximise yield, WP_ET or WP_I, which depends on whether land or water are most limiting. Furthermore, the optimum irrigation schedule to meet the short term needs of individual farmers may differ from that needed for sustainable water resource management.     

生物质炭对磺胺类抗生素在坡耕地紫色土中吸附-解吸及淋溶过程的影响

吸附-解吸是影响抗生素类污染物在土壤中迁移转化及生物有效性的重要过程,本文以川中丘陵区坡耕地紫色土为研究对象,通过批量平衡实验和柱实验研究生物炭施用（投加量0(B0)、39.75 (B1)t/hm2和198.75 (B2) t/hm2）及田间老化作用（夏季干湿交替）对三种典型磺胺类抗生素（磺胺嘧啶（SD）、磺胺二甲基嘧啶（SM2）及磺胺甲恶唑（SMZ））在紫色土中的吸附-解吸和淋溶行为的影响。结果表明：在几种处理中,三种磺胺类抗生素吸附强弱的顺序都表现为SD>SMZ>SM2;与B0处理相比,添加生物炭能增加土壤对三种抗生素的吸附能力,其中SM2的吸附显著增加（P<0.05）,但这种促进作用在经过老化过程后有所减弱。在解吸过程中,三种抗生素的Freundlich常数Kf大小顺序为SD>SMZ>SM2,表明SD在土壤中吸附容量最大且不易解吸,其次是SMZ和SM2;相应的迟滞系数H大小顺序为SD相似文献   

“4.30”闽东暴雨的结构分析

利用2013年4月30日8:00到5月1日8:00的MICAPS资料、NCEP1°×1°再分析资料、福建省区域自动站资料等,分析闽东一场在高空槽、低层切变和地面冷空气共同作用下的冷锋锋前暴雨天气过程。通过物理量结构分析发现,槽前西南急流为此次降水提供了充足的水汽,冷锋过境使得大气条件性不稳定,强的辐散场和锋面南压为此次暴雨提供了强的抬升条件。并浅析此次暴雨对铁观音茶青生产及品质的影响。     

非常规水水质对红壤水分运移参数的影响及其过程模拟

为了探究非常规水水质对亚热带红壤水分运移参数的影响,采用蒸馏水(CK)、再生水(RW)、稀释2,4,6倍再生水(RW-D2、RW-D4、RW-D6)和生活污水(_(WW))等6种不同水质的非常规水模拟红壤水分入渗过程,利用水平土柱吸渗法测定红壤湿润锋运移速率和水分扩散度,应用压力膜仪法测定了土壤水分特征曲线并且借助van Genuchten(VG)模型提取了相应的土壤残余含水量θ_r、土壤饱和含水量θs、α和n等特征参数值。结果表明:不同水质入渗下红壤湿润锋运移速率、水分扩散度均存在着一定差异,湿润锋运移速率由快到慢分别为V_(CK)≈V_(RW-D2)V_(RW-D6)≈V_(RW-D4)V_(WW)V_(RW);在同一含水率下D_(RW-D6)(θ)D_(RW-D4)(θ)D_(WW)(θ)D_(RW-D2)(θ)D_(CK)(θ)D_(RW)(θ)。不同水质处理对VG模型参数变化率的影响程度不同,对α的影响最大,对θ_r的影响最小。因此,非常规水灌溉会降低红壤入渗速率、持水性能以及抗旱能力。     

剪式座椅和前桥空气悬架匹配对拖拉机振动特性的影响

以常发CF700型拖拉机为研究对象,基于MATLAB/SIMULINK为研究平台,选用布置空气弹簧的剪式座椅悬架和前桥空气悬架,建立拖拉机系统的四自由度平面振动模型。通过仿真分析得到,拖拉机机身质心垂向加速度均方根值、俯仰角方向加速度均方根值、座椅垂向加速度均方根值以及前轮胎动载荷均方根值较无悬架拖拉机系统分别下降了16.92%、36.82%、32.71%和20.57%。在GB/T 10910-2004规定的100 m较平滑跑道上对样机进行振动测试并与同等条件下的仿真结果对比,结果表明平均误差率为11.37%,在可接受的范围内,仿真结果可以真实反映拖拉机的振动趋势。