肃南牦牛屠宰性能和肉品质研究

为研究肃南牦牛的屠宰性能及肉品质,揭示其遗传特性,选取12头(公母各半)4岁放牧肃南牦牛进行屠宰试验和肉品质分析,并与文献中已报道的甘南牦牛、天祝白牦牛、雪多牦牛、环湖牦牛等进行了对比分析.结果显示,肃南牦牛的活重和胴体重均高于环湖牦牛和天祝白牦牛,屠宰率高于查乌拉牦牛和环湖牦牛,净肉率高于甘南牦牛和环湖牦牛,熟肉率高...     

成熟期短时渍水胁迫对烤烟碳氮代谢关键酶及主要碳、氮化合物含量的影响

以烤烟云烟97为材料,采用田间试验研究了成熟期短时渍水处理对烤烟碳氮代谢关键酶活性及主要碳、氮化合物含量的影响。结果表明,在烤烟成熟期渍水处理3 d,中部叶片硝酸还原酶活性低于对照,降幅为20.39%;转化酶和淀粉酶活性高于对照,增幅分别为33.14%,56.70%;烟叶淀粉、总氮和烟碱含量有降低趋势,分别下降了2.9,0.74,0.77个百分点,而总糖和还原糖含量有增加趋势,分别上升了1.33,0.46个百分点。说明渍水胁迫使叶片生理代谢紊乱,氮代谢减弱,碳水化合物积累减少。研究结果有助于从生理生化角度揭示成熟期渍水胁迫对烤烟生长和品质形成影响的机制。     

羌塘自然保护区湖泊变化及其原因分析

选取西藏羌塘自然保护区MSS、TM、ETM+数据和1[JP18]∶[JP]100 000地形图,以85° E为中心线,将研究区划分为东西两部分,解译该区域面积大于1 km2的所有湖泊。结果表明：1975-1990年,羌塘自然保护区湖泊呈退缩状态,湖泊个数由388个减少为277个,面积由6 603.3 km²减少到5 539.7 km²,面积减少达16.1%;2005年,湖泊个数比1990年增加164个,达441个,湖泊总面积9 652.2 km²,比1990年增加4 112.5 km²,增幅74.2%。在区域上,表现为东部变化幅度大于西部。同时,重点分析了研究区附近的狮泉河、改则、班戈、申扎、那曲、安多6个气象站1978-2007年的数据。结果显示：6个代表气象站年平均气温、年平均最高气温、年降水量均呈上升趋势,其中东部上升幅度较大,西部变化不明显;年蒸发量呈减少趋势。降水是影响湖泊变化最主要的因素。     

野生龙葵果中营养成分的研究

本研究对野生龙葵果营养成分进行了比较全面地分析测试,对矿物质及维生素含量进行分析的基础上,对野生龙葵果的其它营养成分进行了分析,并与一些常用果蔬进行了对比研究。结果表明,野生龙葵果含有丰富的营养成分。     

镉在黄瓜幼苗中的化学形态及亚细胞分布

为探究黄瓜幼苗对镉的吸收累积特性,将黄瓜幼苗置于6种镉浓度梯度(0、10、50、100、200、300μmol·L~(-1))营养液中培养17 d,测定黄瓜幼苗地上部和根部的镉含量以及镉在叶片的亚细胞分布和其化学形态分布。结果表明:随镉浓度升高,转移系数逐渐降低,黄瓜由根向地上部对镉的转运能力减弱。时间或浓度处理均会显著增加黄瓜叶片各亚细胞组分镉含量,镉的富集比例趋势表现为可溶性部分细胞壁细胞器,其中可溶性部分镉含量占44.88%～84.94%,远大于细胞器(3.10%～17.05%)与细胞壁(11.20%～39.66%)。相同时间下,随镉处理浓度的增加,镉在细胞壁组分占比先升高后降低,可溶性部分镉的占比先降低后升高。同时随着处理时间延长,细胞壁组分镉占比降低,可溶性部分镉占比升高。黄瓜叶片中NaCl提取态镉占比最高(33.69%～54.23%),但随着镉浓度提高,乙醇提取态、H2O提取态镉占比升高。当镉浓度达到300μmol·L~(-1)时,黄瓜叶片中的镉形态以乙醇提取态、H2O提取态和NaCl提取态占优势。总的来看,在器官水平上,黄瓜通过限制镉由根部向地上部传递的方式,降低镉对黄瓜地上部的毒害;亚细胞水平上,细胞壁对镉的吸持和液泡区室化是黄瓜对镉胁迫下的重要解毒方式,其中以液泡的区室化占主导位置;在化学形态分布上,镉的化学形态转化也是黄瓜应对镉胁迫的重要耐性策略。     

西藏玛旁雍错流域湖泊面积变化及成因分析

利用1975年地形图、1990年、1999-2009年TM卫星遥感影像和近35 a(1975-2009年)气温、降水、积雪日数、蒸发量等气候资料,分析研究了位于西藏阿里地区南部普兰县境内玛旁雍错、拉昂错湖泊面积变化对气候变化的响应。结果表明：在过去35 a里玛旁雍错、拉昂错面积先减少后增加,总体呈减小趋势,到2009年玛旁雍错面积为415.44 km²,拉昂错面积为261.36 km²。与1975年相比2个湖泊面积分别减少了1.56 km²和11.01 km²;受气候变暖的影响,流域附近的冰川面积也在加速退缩。对1975-2009年普兰县气象资料统计分析可知,降水量减少是导致湖泊面积缩小的主要原因,蒸发量不显著的增加及雪冰消融也是近几年湖泊面积波动变化的原因之一。     

烤烟新品种南江3号在贵州烟区的生态适应性研究

以K326为对照,研究了烤烟新品种南江3号在贵州五大具有生态代表性烟区的农艺性状、生育期性状、抗病特征、经济性状、外观质量及吸食品质等指标。结果表明:与K326相比,南江3号在贵州烟区长势强、生育期长、抗病力强、产量和产值高、烟叶外观质量好,吸食品质与K326相当,在贵州烟区具有很好的生态适应性。     

Associated luteinizing hormone-releasing hormone and luteinizing hormone secretion in ovariectomized gilts.

The secretion of luteinizing hormone-releasing hormone (LHRH) and its temporal association with pulses of luteinizing hormone (LH) was examined in ovariectomized prepuberal gilts. Push-pull cannulae (PPC) were implanted within the anterior pituitary gland and LHRH was quantified from 10 min (200 microliters) perfusate samples. Serum LH concentrations were determined from jugular vein blood obtained at the midpoint of perfusate collection. Initial studies without collection of blood samples, indicated that LHRH secretion in the ovariectomized gilt was pulsatile with pulses comprised of one to three samples. However, most pulses were probably of rapid onset and short duration, since they comprised only one sample. Greater LHRH pulse amplitudes were associated with PPC locations within medial regions of the anterior pituitary close to the median eminence. In studies which involved blood collection, LH secretion was not affected by push-pull perfusion of the anterior pituitary gland in most gilts, however, adaptation of pigs to the sampling procedures was essential for prolonged sampling. There was a close temporal relationship between perfusate LHRH pulses and serum LH pulses with LHRH pulses occurring coincident or one sample preceding serum LH pulses. There were occasional LHRH pulses without LH pulses and LH pulses without detectable LHRH pulses. These results provide direct evidence that pulsatile LHRH secretion is associated with pulsatile LH secretion in ovariectomized gilts. In addition, PPC perfusion of the anterior pituitary is a viable procedure for assessing hypothalamic hypophyseal neurohormone relationships.     

Long-term nutritional effects on the primary liver and kidney metabolism in rainbow trout, Oncorhynchus mykiss (Walbaum): adaptive response to a high-protein/non-carbohydrate diet and starvation of glucose 6-phosphate dehydrogenase activity

The adaptive response of the kinetics of glucose 6-phosphate dehydrogenase (G6PDH) was studied in trout liver and kidney after feeding (control or high-protein/non-carbohydrate diet) or starving for 30 days, as well as influences on growth and other nutritive parameters. Typical Michaelis-Menten kinetics were found for the hepatic catalysis of G6PDH under all conditions studied, without evidence of sigmoidicity. The administration of a high-protein/non-carbohydrate diet (61.0% protein, 7.9% lipids) produced no significant changes in specific activity or other kinetic parameters of the liver enzyme. This nutritional situation caused a significant daily increase in relative growth (20%) and feed efficiency (13.5%), as well as a 13% decrease in the protein-conversion efficiency, with respect to the control diet (46% protein, 8% lipids, 22% carbohydrates). On the other hand, long-term starvation (30 days), as a lipolytic condition, significantly decreased the activity and catalytic efficiency of hepatic G6PDH, by almost 45%, without significant changes in the K_m and activity-ratio values. These changes agree with a fall in the intracellular concentration of the enzyme as a consequence of a protein-repression process. The activity of the renal G6PDH was less than in the liver of control fish, and no variation in kinetics was found under the high-protein diet or starvation. This behaviour clearly demonstrates that the kidney pentose-phosphate pathway showed no adaptive response in relation to synthesis of fatty acids and other lipids.     

民和县良种肉牛的杂交试验

[目的]为了验证优良品种改良本地黄牛的效果,[方法]运用三个杂交组合在民和县用引进的良种肉牛西门塔尔、利木赞和皮尔蒙特牛改良当地黄牛。[结果]表明F1不同年龄的生长速度和体尺指标均明显于本地黄牛（P〈0.01）,说明良种肉牛改良本地黄牛效果明显;在不同杂交后代的比较中,皮×黄F1各年龄段体重均高于西×黄F1、利×黄F1,杂交组合最为理想。[结论]说明不同的杂交组合具有不同的效果。