低场核磁共振分析聚乙二醇对萌发期水稻种子水分吸收的影响   总被引：2，自引：2，他引：0  

杨洪伟  张丽颖  纪建伟  王成  王晓冬  宋平  宋鹏 《农业工程学报》2018,34(17):276-283

为研究聚乙二醇(PEG,polyethylene glycol)处理下水稻种子萌发过程中内部水分分布和变化规律,进而揭示水稻耐旱性在水分吸收规律上的重要特征。应用低场核磁共振的T2弛豫谱和质子密度加权成像分析了PEG处理下水稻种子萌发过程中的水分变化,研究了利用蒸馏水(对照)和质量分数分别为10%、20%PEG6000处理对两个水稻品种旱9710、辽星1发芽指标的影响,以及对两个水稻品种萌发0、6、22、48、72 h吸水量的影响,确定单位质量核磁信号幅值与水稻种子湿基含水率的回归函数关系。发芽指标检测结果显示:旱9710耐旱性高于辽星1。质子密度加权成像结果显示:在水分吸收初期,水分子直接通过种子表面裂缝进入种子体内,胚乳中的淀粉粒等物质开始吸水膨胀,种子体积增大。24 h后,种子内营养物质向种胚流动。PEG处理下,水稻种子吸水量明显减少,发芽速度明显降低,且PEG质量分数越高,发芽速度越慢。基于核磁共振理论及T2弛豫谱的多组分特征,当反演频率为10 000时,水稻种子萌发过程中的水分分为束缚水与自由水两部分。T2弛豫谱结果表明:在蒸馏水和质量分数分别为10%、20%PEG处理下,种子湿基含水率和核磁信号幅值均逐渐增长。PEG处理下,核磁信号幅值增长相比对照处理显著降低(P0.05)。PEG处理抑制了两个水稻品种种子对水分的吸收,PEG质量分数越高,抑制作用越强。PEG处理24 h后,耐旱性强的水稻品种吸水率相比对照处理的降低幅度小于耐旱性弱的品种。回归分析表明,3种处理下,核磁信号幅值和湿基含水率具有一致的线性关系(R2=0.983),由回归方程可以求得水稻种子萌发过程中各状态水分的含量。试验为研究水稻种子萌发过程对干旱胁迫的反应机制,开发种子水分微观活体无损检测技术等方面的研究提供理论支持和数据参考。  相似文献   

小麦条锈菌效应蛋白基因 PSTG_23616的时空表达特征分析     

宋平  谭成龙  郭嘉  戚拓  刘芃  郭军 《西北农业学报》2016,25(9):1279-1288

明确条锈菌(Puccinia striiformis f.sp.tritici,Pst)效应蛋白基因PSTG_23616的时空表达特征,旨在解析该基因在病菌生长发育及致病过程中的作用。利用RT-PCR和PCR克隆获得PSTG-23616的cDNA和基因组DNA全长;借助生物信息学软件分析PSTG-23616蛋白序列特征并构建系统进化树;通过酵母分泌系统、农杆菌介导的瞬时表达系统、实时荧光定量RT-PCR(qRT-PCR)、亚细胞定位技术初步明确该基因的功能。结果表明,PSTG_23616基因组全长937bp,开放阅读框(open reading frame,ORF)全长699bp。生物信息学软件预测结果显示,PSTG-23616信号肽为位于N端的1~22个氨基酸;酵母分泌系统分析表明,PSTG-23616的信号肽具有分泌功能,为典型的分泌蛋白;注射含有PSTG_23616的重组农杆菌菌液,可抑制由BAX引起的细胞程序性死亡(Programmed cell death,PCD)反应;qRT-PCR结果表明,PSTG_23616在小麦条锈菌初侵染过程中一直上调表达,24h表达量达到顶峰;亚细胞定位分析表明,PSTG_23616在整个细胞均有分布。推测,该效应蛋白参与条锈菌侵染结构的分化,同时在条锈菌与小麦互作过程中发挥毒性功能。  相似文献   

Experimental study on eccentric compression behaviour of autoclaved flyash lime brick masonry     

QIN Shi hong  CAO Huan ming  NI Xiao jun  LUO Wan kang 《保鲜与加工》2009,(7):809-814

To study the eccentric compression performance of autoclaved flyash lime brick masonry, and validate the applicability of current code’s calculation method, static tests on 36 eccentrically loaded puncheons of standard autoclaved flyash lime solid brick and KP1 type perforated brick with circular holes masonry are carried out by applying eccentric load on the top of the specimens. The bearing capacity of eccentric compression is analyzed using plane section assumption and ideal stress/strain curve. The features and shapes during the process of failure are obtained and the eccentric compression impact factor formula is also obtained by regression analysis of experimental data. With eccentricity increasing, cracking load and failure load are gradually decreased, and the failure features gradually change into large eccentric compression from axial compression. Most test values of bearing capacity under eccentric compression are higher than code calculating values. The average strain distribution in the section is in accordance with the plane section assumption. The theoretical analysis method used is feasible, current code’s formula can be used to calculate the bearing capacity of flyash lime brick masonry under eccentric compression.  相似文献   

构建多层次供求均衡的现代农村金融体系初探   总被引：1，自引：0，他引：1  

宋平  罗剑朝 《西北农业学报》2009,18(6):389-393

为探讨现代农村金融运行机制,促进农村经济发展,对中国农村金融体系现状、金融供求矛盾和存在的主要问题进行了调研分析,认为中国农村金融表面上是供给量不足的问题,实际上是结构性失衡的问题.针对这些问题,提出了构建多层次供求均衡的现代农村金融体系的一种初步模式.  相似文献   

不同方法提取沙田柚柚皮精油成分的研究     

宋平  宋元德 《保鲜与加工》2014,14(1):41-46

以长寿沙田柚柚皮作为试验材料,采用冷压法、水蒸气蒸馏法和C02超临界萃取法三种方法提取柚皮精油．研究不同方法提取柚皮精油的成分与含量。结果表明．三种提取方法的精油提取率分别为0．126％、0．401％和0．252％;采用GC—MS检测分析结果表明,三种方法所得精油有效成分的种类分别为49种、35种和37种,其中有22种成分相同,包括6种最高含量的成分（0．4％）;水蒸气蒸馏法在提取过程中的高温会导致部分精油成分挥发或分解,CO2超临界萃取法提取前的冻干过程也会使部分精油成分随水分流失．冷压法依然是可保持沙田柚柚皮精油成分最有效的提取方法。  相似文献   

低磷胁迫下马尾松无性系磷效率性状对氮沉降的响应   总被引：2，自引：0，他引：2  

宋平  张一  张蕊  周志春  丰忠平 《植物营养与肥料学报》2017,23(2):502-511

【目的】剖析不同类型低磷胁迫下马尾松应对大气氮沉降的生长表现和适应机制,为在大气氮沉降背景下选育营养高效利用的马尾松速生优质新品种提供理论依据。 【方法】以来自马尾松 (Pinus massoniana) 全同胞子代的 5 个优良无性系 1 年生扦插幼苗为材料,分别在同质低磷 (介质表层与深层均缺磷) 和异质低磷 (介质表层磷丰富、深层缺磷) 两种土壤磷素环境下设置两种浓度梯度的模拟氮沉降试验,以研究低磷胁迫下马尾松无性系苗木生长、根系发育及氮、磷效率对模拟氮沉降的响应差异和规律。 【结果】1) 不同类型低磷胁迫下马尾松苗高和干物质积累量均表现出显著的无性系变异,且在同质低磷下存在明显的无性系 × 氮交互效应 (P < 0.05)。2) 马尾松无性系在不同类型低磷胁迫下应对氮沉降的适应机制有所差异。同质低磷、高氮环境下,33-4 和 19-5 等生长势较强的无性系,其根系长度、根表面积以及根分泌的酸性磷酸酶活性显著高于生长势较弱的无性系,干物质积累量与酸性磷酸酶活性之间的相关性增强,表明根系可通过增加在土壤中的分布面积和提高酸性磷酸酶活性来应对高氮、低磷的外界环境;异质低磷下,生长势较强的无性系,其根系长度和表面积在高氮沉降下显著增加,但比根长反而显著下降,意味着根系在高氮下增加吸收面积的同时,降低自身内部消耗可能是马尾松高磷效率的重要生物学基础之一。3) 马尾松无性系的磷吸收效率受氮沉降影响较大,在不同氮、磷水平下,其磷吸收效率与氮吸收效率均呈极显著正相关 (P < 0.01),表明模拟氮沉降有利于马尾松无性系对土壤中磷素的活化吸收,但磷利用效率无显著差异。4) 马尾松无性系的干物质积累量、根系长度、根表面积以及根分泌的酸性磷酸酶活性等指标的变幅较大,且无性系重复力均达到 0.75 (P < 0.05) 以上,这为高氮、低磷环境下马尾松耐受型植株的选择提供了可能。 【结论】以马尾松根系形态和根分泌的酸性磷酸酶活性变异为突破口,选育氮沉降下具有高磷效率的马尾松无性系将有利于遗传效益的提高。  相似文献   

Embedded terminal receiving capability matching in multimedia file transmission     

WANG Hai wei  NI Hong  SUN Peng  ZHU Xiao yong 《保鲜与加工》2010,(8):29-35

A novel transport protocol for large scaled multimedia file EMFTP (Embedded Multimedia File Transfer Protocol) is proposed to match the receiving capability of embedded terminal with sufficient network bandwidth. EMFTP is an application level protocol using UDP, and adopts a method of uniform retransmission as its error recovery strategy and it also introduces an improved DAIMD (AIMD with decreasing increases) rate control algorithm based on bandwidth probe. It can improve the data transfer rate with a low resource taken of embedded client. As the experimental result shows, compared with UDT and FTP protocol implemented on embedded terminal, EMFTP data transfer rate is increased by 3% and 17% respectively, the embedded client CPU occupancy ratios are reduced by 50.3% and 42.3% separately, and memory usage reduced by 15% and 4%.  相似文献   

Metabolic Profiling of Glucosinolates, Anthocyanins, Carotenoids, and Other Secondary Metabolites in Kohlrabi (Brassica oleracea var. gongylodes)     

Park WT  Kim JK  Park S  Lee SW  Li X  Kim YB  Uddin MR  Park NI  Kim SJ  Park SU 《Journal of agricultural and food chemistry》2012,60(33):8111-8116

We profiled and quantified glucosinolates, anthocyanins, carotenoids, and other secondary metabolites in the skin and flesh of pale green and purple kohlrabis. Analysis of these distinct kohlrabis revealed the presence of 8 glucosinolates, 12 anthocyanins, 2 carotenoids, and 7 phenylpropanoids. Glucosinolate contents varied among the different parts and types of kohlrabi. Glucoerucin contents were 4-fold higher in the flesh of purple kohlrabi than those in the skin. Among the 12 anthocyanins, cyanidin 3-(feruloyl)(sinapoyl) diglucoside-5-glucoside levels were the highest. Carotenoid levels were much higher in the skins than the flesh of both types of kohlrabi. The levels of most phenylpropanoids were higher in purple kohlrabi than in pale green ones. trans-Cinnamic acid content was 12.7-fold higher in the flesh of purple kohlrabi than that in the pale green ones. Thus, the amounts of glucosinolates, anthocyanins, carotenoids, and phenylpropanoids varied widely, and the variations in these compounds between the two types of kohlrabi were significant.  相似文献   

Biofortification of tomato (Solanum lycopersicum) fruit with the anticancer compound methylselenocysteine using a selenocysteine methyltransferase from a selenium hyperaccumulator     

Brummell DA  Watson LM  Pathirana R  Joyce NI  West PJ  Hunter DA  McKenzie MJ 《Journal of agricultural and food chemistry》2011,59(20):10987-10994

Methylselenocysteine (MeSeCys) is an amino acid derivative that possesses potent anticancer activity in animals. Plants that can tolerate growth on soils with high Se content, known as Se hyperaccumulators, do so by converting inorganic Se to MeSeCys by the enzyme selenocysteine methyltransferase (SMT). A cDNA encoding the SMT from a Se hyperaccumulator was overexpressed in tomato (Solanum lycopersicum). Transgenic plants were provided with selenite or selenate to the roots during fruit development, and liquid chromatography-mass spectrometry was used to show that MeSeCys accumulated in the fruit but not in the leaves. Depending on the transgenic line and Se treatment, up to 16% of the total Se in the fruit was present as MeSeCys. MeSeCys was produced more effectively from selenite on a percentage conversion basis, but greater accumulation of MeSeCys could be achieved from selenate due to its better translocation from the roots. MeSeCys was heat stable and survived processing of the fruit to tomato juice.  相似文献   

巴西里贝拉山谷的秘密     

宋平 《中国花卉园艺》2008,(3):43-45

巴西的园艺业有一个鲜为人知的秘密：在圣保罗州（Saoaul）南端的几个城镇,集中了约323家观赏花卉种植者,其栽培总面积达800公顷,这几个城镇已成为圣保罗州花卉种植的主要地区。该地区位于里贝拉河与大西洋交汇的低洼处,有着特别的微气候,年均温度在24℃,相对湿度85％,犹如天然温室一样。  相似文献