添加物和消化液对牛和小鼠类胚胎干细胞克隆效率的影响

研究了犊牛血清、饲养层、培养液、添加物和消化液对牛和小鼠类胚胎干细胞克隆效率的影响。结果表明 ,在 2 4h内使小鼠胚胎贴壁率达 86 %以上的犊牛血清可用于小鼠和牛胚胎干细胞的分离和克隆 ;在 ES细胞培养液中 ,犊牛血清体积分数以 15 %～ 2 0 %为宜 ,在 DMEM(L )培养液中添加 0 .1μm ol/ L Na2 Se O3+0 .1mm ol/ Lβ-巯基乙醇 +10 ng/ m L IGF+10 0 0 ng/ m L L IF,能显著提高牛 ES细胞分离与克隆效率 ;低糖 DMEM比TCM199和高糖 DMEM更适宜于牛 ES细胞的分离。优秀胚胎形成的团状 ICM更适宜于分离与克隆 ES细胞 ,在37℃用低体积分数消化液处理 ICM或 ES细胞集落 ,再以机械将其离散为细胞小块 ,ES细胞克隆效率最高     

油菜、荞麦根分泌物中糖及有机酸组分的研究

利用连续流动收集系统收集了油菜、荞麦根分泌物，对介质ｐＨ变化、分泌物中碳水化合物组成及有机酸进行了测定。结果表明，荞麦、油菜生长介质中ｐＨ值变化的差异反映了它们泌质子能力的差异。在油菜分泌物中检测出高水平的鼠李糖，在荞麦中则是阿拉伯糖含量最高。草酸、琥珀酸是两种作物根分泌物的主要有机酸。苹果酸、柠檬酸在油菜根分泌物中没有检测出。     

年龄对非妊娠母马垂体促性腺激素细胞形态计测学的影响

利用免疫组织化学和形态计测学的方法,在繁殖季节测量不同年龄非妊娠母马垂体促性腺激素细胞的数量和直径结果:非妊娠母马垂体促性腺激素细胞的直径伴随着年龄的增长而增大,但达到老年后却减小;非妊娠老年母马的FSH细胞数目显著地高于幼年、青年和中年母马(P<0. 05),而老年母马LH细胞的数目则显著地低于其它年龄的母马(P<0. 05)。结果表明:非妊娠母马垂体促性腺细胞大小及数量与年龄的变化有关。     

关于农业生产中的经济问题——试论社会主义农业生产经济学的研究对象与任务

我国正在从事农业现代化的建设工作,同时也在不同范围和深度上试行农村经济管理体制的改革。这是现阶段我国农业发展工作中的两件大事。现在已经开始看到明显的效果。这两大改革解决了我国农业发展中的一些问题,同时也出现了许多新的农村经济问题,有些老问题也在新形式下再现出来。例如,在落实生产队经营自主权过程中,出现了怎样把生产队经营自主权与国家计划结合起来的问题;在活跃农村集市     

滴灌技术在甘蔗生产上的应用前景

介绍了甘蔗滴灌类型、国内甘蔗滴灌的应用现状及其优点,指出甘蔗应用地埋式滴灌应注意的问题,提出了滴灌技术在甘蔗生产上的应用前景。     

Nano-structure and properties of maize zein studied by atomic force microscopy

Atomic force microscopy was used to investigate the nanostructure of zein from maize (Zea mays). In aqueous ethanol solution zein exists as small globules with diameters between 150 and 550 nm. The mechanism of zein film formation was also explored. The characteristic film structure consists of a meshwork composed of doughnut structures formed from asymmetric rods joined to each other.     

生物脱胶苎麻纤维性能研究

应用一种简便、廉价的细菌脱胶方法对苎麻进行脱胶，研究脱胶后的苎麻纤维性能。结果表明，苎麻细菌脱胶后残胶率1．82％，达到了脱胶要求。且松散了苎麻纤维横截面组织结构，对苎麻中纤维素无破坏，提高了上染色率12％左右，单纤维强力比碱液脱胶的大0．15N／tex，对白度影响不大。说明该脱胶法是一种绿色生产工艺。     

Differences in Grain Yield and Quality in Main and Ratoon Rice in Southern Henan Province

【Objective】 The combination of mid-season rice+ratoon rice is a new pattern of rice planting in southern Henan Province. However, the changes in grain yield and quality between the main and ratoon seasons remain unclear. Clarifying the changing law of grain yield and rice quality can lay a theoretical and practical basis for the screening of ratoon rice varieties with higher grain yield and better rice quality in southern Henan Province. 【Method】 In this study, 12 hybrid indica rice combinations suitable for single-cropping rice were used as materials under local high-yield cultivation conditions. The tested combinations were divided into four types according to their yields in main and ratoon seasons: BH, both high grain yields in main and ratoon season; HL, high grain yield in main season and low grain yield in ratoon season; LH, low grain yield in main season and high yield in ratoon season; BL, both low grain yields in main and ratoon seasons. The difference in rice quality was also analyzed. 【Result】 1) The processing quality and appearance quality in ratoon season were significantly improved, however, the protein contents decreased, and the eating quality of rice was improved to different extents as compared with those in main season; 2) Except for BL type (only one combination, Shenliangyou 11), the processing quality of BH and HL was better, and HL has better appearance quality and cooking and eating quality. There was no significant difference in protein contents among different yield types in main season, while in ratoon season, the protein contents in BH were 10.7 % higher than those in HL, and 1.75% lower than those in LH. 3) The effect of daily average temperature after full heading on grain quality was far greater than the sunshine hours, and the relatively low average daily temperature after full heading in ratoon season was the main reason for its better grain quality. 【Conclusion】 Based on higher grain yield and better rice quality, Liangyou 6326, Tianliangyou 616, Guangliangyou 476 and Fengliangyouxiang 1 were suitable varieties for ratoon cultivation in southern Henan Province.     

Effects of proteolysis and mechanism of gel weakening in heat-induced gelation of fish myosin

Addition of papain decreased the onset temperature and the rate at which G' developed during heat-induced gelation of arrowtooth flounder myosin. Frequency sweep results revealed that G' markedly decreased in proportion to the amount of papain added. However, use of E-64, a cysteine proteinase inhibitor, reversed the effects of papain and protected myosin heavy chain from degradation. DSC thermograms indicated papain significantly decreased the enthalpy required to induce myosin denaturation without significant changes in onset and maximum transition temperatures. Thermal denaturation kinetics indicated decreases in both the activation energy and the rate of myosin denaturation. CD studies revealed a rapid decrease in alpha-helical content, indicating the initial degradation of myosin molecules mostly occurred in the tail region. These results suggested that proteolysis affected thermal properties and reactivity of myosin during heating. Although myosin gel could be formed, structural disruption resulted in lower gelling ability and rigidity of the formed gel.     

播种量和穗肥施氮量对优质食味直播水稻产量和品质的影响

播种量是影响直播水稻产量的关键因素之一,但其对优质食味水稻产量和品质的影响研究相对较少。施用穗肥是水稻高产栽培的重要措施,但穗肥施氮量对优质食味直播水稻产量和品质的调节效应尚不清楚。本研究以3个江苏省代表性优质食味水稻苏香粳3号、南粳5055和南粳9108为材料,在行距固定为25 cm条件下,分析了60、90、120、150和180 kg hm–2等5个播种量对上述品种产量和品质的影响,并观察了适宜播种量条件下穗肥施氮量对优质食味水稻产量和品质的调节效应。主要结果表明:(1)苏香粳3号、南粳5055和南粳9108的产量均随播种量增加呈先升后降的趋势。3个品种高产最适播种量分别为130.2～136.5、118.3～119.3和90.0～96.4 kg hm–2。稻米加工品质与播种量呈不同程度负相关,而垩白粒率、垩白度、蛋白质含量、米粉消解值与播种量呈显著或极显著正相关。胶稠度、直链淀粉含量、食味值和崩解值与播种量均呈显著或极显著负相关。(2)在高产适宜播种量条件下,与常规穗肥施氮量相比,穗肥施氮量减半对南粳5055和南粳9108的产量无明显影响,但可明显改善稻米的外观品质和食味值。上述结...