低温处理对紫色小白菜品质及光合特性的影响

以‘紫薇’不结球紫色小白菜作为试验材料,研究不同低温处理对紫色小白菜营养品质及光合作用的影响。结果表明:(1)紫色小白菜花青苷的含量变化表现为随低温处理程度的加重先升高后下降。(2)随着低温处理程度的加重,紫色小白菜的类黄酮含量、可溶性糖含量、可溶性蛋白含量、维生素C含量、叶绿素a、叶绿素b、叶绿素(a+b)、类胡萝卜素含量均呈现先缓慢上升后急剧下降的变化规律。(3)随着低温处理程度的加重,叶片的光合速率、蒸腾速率、气孔导度、PSⅡ最大光化学效率(ψPO)、光合性能指数(PIABS)均呈现出显著下降的趋势。(4)光合性能指数PIABS随着低温处理的加重而呈现先缓慢上升后急剧下降的趋势。以有活性的反应中心(RC)为基础的叶绿素荧光参数表明,紫色小白菜叶片单位反应中心吸收的光能(ABS/RC)、单位反应中心捕获的光能(TRO/RC)、单位反应中心传递的能量(ETO/RC)和单位反应中心热耗散的能量(DIO/RC)均随着处理温度的降低而呈现出先下降后上升的趋势。以单位受光面积(CS)为基础的叶绿素荧光参数表明,低温处理后,单位面积捕获的光能(TRO/CS)、单位面积的热耗散(DIO/CS)均随处理温度的降低而呈现先下降后上升的趋势,而单位面积电子传递的量子产额(ETO/CS)和叶片单位面积上有活性的反应中心数量(RC/CSO)则呈现出先上升后降低的变化规律。紫色小白菜叶片中PSⅡ最大光化学效率(ψPO)、将电子传递到电子传递链中QA-下游的其他电子受体的概率(ΨO)、反应中心吸收的光能用于电子传递的量子产额(ψEO)随着处理温度的降低而呈现先缓慢上升后急剧下降的趋势,而表示叶片的相对可变荧光(VJ)、K相可变荧光占J相可变荧光比例(WK)以及QA被还原的最大速率(MO)均随着处理温度的降低而先下降后逐渐上升,说明过度的低温环境使QA下游电子受体接受电子能力明显下降,电子传递受到抑制,从而造成QA-或QA2-的大量积累,致使PSⅡ反应中心的活性状态受到破坏。综上分析表明,TⅡ处理最有利于提高紫色小白菜光能利用率,增加光合色素含量,促进了部分营养品质的改善,可为紫色小白菜耐低温生产的推广运用提供理论基础。     

添加不同乳酸菌对燕麦低温青贮发酵的影响

为了分析前期筛选出较耐低温不同乳酸菌（Lactic acid bacteria,LAB）对燕麦青贮发酵的影响,本试验以'陇燕5号’燕麦为原料,设置对照（CK）、商用菌株SLI和较耐低温菌株OL77,OL54及OL122共5个处理,在15℃,10℃和5℃低温下自然发酵45 d后进行营养成分、发酵品质和微生物数量的测定。结果表明：乳酸菌添加及温度对燕麦青贮的营养成分、发酵品质、微生物数量均有极显著影响。随着温度从15℃降至5℃,CK的粗蛋白（Crude protein,CP）降低了18.92%,氨态氮（Ammonia nitrogen,NH₃-N）增加了58.47%;与SLI相比,耐低温菌株OL77在提高干物质（Dry matter,DM）和CP、降低NH₃-N水平方面的效果优于OL54和OL122;添加剂在各温度处理下均提高了燕麦青贮发酵品质,15℃下添加OL77后燕麦青贮的pH值较CK和SLI分别降低了8.94%和1.57%,乳酸分别增加了79.23%和29.41%,乳酸菌数量分别增加了50.24%和15.61%。3个耐低温菌株中,OL77总体表现最优,促进燕麦低温发酵的效果最好。     

程序升温-气相色谱技术同时检测饲料中10种防腐剂

实验采用DB-5MS毛细管柱结合程序升温技术的气相色谱法在7 min内同时分离和检测了饲料中丙酸（PA）、山梨酸（SA）、苯甲酸（BA）、脱氢乙酸（DHA）、对羟基苯甲酸甲酯（MP）、对羟基苯甲酸乙酯（EP）、对羟基苯甲酸丙酯（PP）、对羟基苯甲酸丁酯（BP）、对羟基苯甲酸异丙酯（IPP）、对羟基苯甲酸异丁酯（IBP）等10种防腐剂。结果表明,10种添加剂的线性相关系数r≥0.9989,检测限为0.1～5μg/mL,样品平均回收率为81.5%～90.0%,相对标准偏差小于5.0%。     

甘肃高山细毛羊细管鲜精低温保存效果研究

为了研究甘肃高山细毛羊种公羊细管精液低温保存的效果.用葡萄糖、柠檬酸钠、鲜奶和卵黄为主要成分配制了3种稀释液,10倍稀释精液,并在4℃保存,分别在12h,24 h,36h,48 h,60h和72 h观测精子活力和人工授精受胎率.结果显示,配方Ⅲ稀释精液后,细管封装,4℃保存,72 h后精子活力可达0.49,与配方Ⅰ和Ⅱ差异显著,而且配方Ⅲ稀释精液后,在远距离输精后受胎率可达78.3％.以柠檬酸钠和葡萄糖为基础,添加卵黄和TCM199,在4℃下,能有效保护甘肃高山细毛羊精液,延长精子寿命,且在3d内可以满足远距离人工授精要求,有效利用种公羊价值.     

温度对垂穗披碱草青贮品质的影响

为探讨不同温度下青藏高原垂穗披碱草（Elymus nutans）贮藏过程中发酵品质的动态变化,本研究以采自青海省果洛藏族自治州的垂穗披碱草为青贮原料,在当地完成塑料袋青贮后带回实验室分别置于15和25 ℃下进行青贮,在贮藏2、4、6、8、12、14、30、60 d后开袋,测定其相关指标。结果表明,15 ℃处理下,pH值缓慢下降至5.68,乳酸含量1.44%,青贮效果不佳;25 ℃增加了乳酸含量（6.21%）,使pH值显著降至4.27（P<0.05）,取得了良好的青贮效果。随着贮藏时间的延长,AN/TN值逐渐增加,乙酸含量在发酵初期(4 d内)显著增加（P<0.05）,在发酵后期水溶性碳水化合物含量显著降低（P<0.05）,之后保持稳定。温度和发酵时间对粗蛋白、中性洗涤纤维和酸性洗涤纤维含量没有显著影响（P>0.05）。     

五种草坪草生态适应性的研究

通过对5种草坪草在不同极限温度、水分和光照条件下的生理反应研究了这几种草坪草的生态适应能力。结果表明，狗牙根和高羊茅有较强的环境适应性，早熟禾、黑麦草和紫羊茅的环境适应性相对较弱。但它们有特殊的生理环境适应性。如普通早熟禾经研究是短日照喜温植物，有较好的耐荫性。     

Evaluation of Thermal Environment of Cowshed and Correlation Analysis Between Thermal Parameter and Physiological Parameter of Dairy Cows in Central Plain of Hebei

The purpose of this study was to evaluate thermal environment of cowshed in four seasons in central plain of Hebei,and analyze the correlation between the temperature parameters and physiological indexes of dairy cows.Three dairy cow houses with different building structures were selected,the thermal parameters (ambient temperature (Ta) and relative humidity (RH)) and physiological parameters (respiratory rate,rectal temperature and body surface temperature) were detected.The results showed that the Ta,RH and index of temperature and humidity (THI) changed significantly in four seasons (P<0.05),the average daily temperature in summer was the highest (28.59 ℃),and the average daily temperature in winter was the lowest (1.55 ℃).In summer,dairy cows were suffering from mild heat stress for 15.5 h every day,and from moderate heat stress for 6.0 h.In winter,dairy cows were under mild cold stress for an average of 12.0 h per day.The Ta and THI of three cowsheds in each season had no significant differece (P>0.05),except for that in winter.Compared with the cowshed with low wall or roller blind,the average Ta in the cowshed with only roof was 0.80-1.27 ℃ higher in summer and 1.36-1.84 ℃ lower in winter.In addition,the physiological parameters of dairy cows were extremely significantly higher in summer than those in other seasons (P<0.01).The respiration frequency or rectal temperature of cows among cowsheds in summer were significantly different (P<0.05),and the seasonal difference in body surface temperature was significant (P<0.05).Correlation analysis of thermal parameters and cow physiological parameters showed that the respiratory frequency,rectal temperature and body surface temperature were positively correlated with THI and Ta (P<0.05).However,there was no significant correlation between physiological parameters and RH (P>0.05).The results provided scientific basis for environment evaluation of cows,and physiological status of dairy cows were inferred according to environmental thermal parameters,which provided data for occurrence and early warning of stress.     

Diagnostic value of rectal temperature of African cattle of variable coat colour infected with trypanosomes and tick-borne infections

Diagnosis of major endemic bovine parasitic diseases in sub-Saharan Africa such as trypanosomosis, theileriosis, anaplasmosis, babesiosis and cowdriosis is increasingly relying on clinical diagnosis due to deterioration of veterinary services and laboratory facilities. Pyrexia is a common clinical feature of aforementioned diseases whose detection relies on measurement of rectal temperature. The research undertaken in this study was aimed at assessing the effects of diurnal changes and variable coat colour of indigenous Nkedi Zebu cattle on the diagnostic value of rectal temperature under tropical conditions. The results revealed that variation in rectal temperature was significantly influenced by time of day it was taken and by the coat colour of the Nkedi Zebu cattle (P < 0.001). Rectal temperature experienced diurnal changes: steadily rising to reach a peak at 17.00 h before declining. The mean rectal temperature of unhealthy cattle was significantly higher (P < 0.05) than that of the healthy ones only between 13.00 and 17.00 h of the day. During which period the proportion of unhealthy cattle having a rectal temperature of 39.4 °C or higher was significantly higher than that of healthy ones (P < 0.001). Regarding the variable coat colour of indigenous breeds, rectal temperature among cattle of different coat colours was significantly different (P < 0.05). In conclusion it is important to consider diurnal changes in rectal temperature and differences due to variable coat colour of indigenous African breeds when measuring rectal temperature for assessing pyrexia, during clinical diagnosis of bovine trypanosomosis and tick-borne diseases that are endemic in many countries in sub-Saharan Africa.     

蚕丝脱胶方法的比较分析

对高温高压水、尿素溶液和碳酸钠溶液煮沸的蚕丝脱胶方法作了比较研究。结果表明 ,蚕丝在高温高压条件下丝胶蛋白易于溶解 ,脱胶率达 80 %以上 ,获得的丝胶分子量大 (10～ 2 0 0kD) ;在碱性的碳酸钠溶液中煮沸脱胶 ,丝胶蛋白易于降解或水解 ,其回收的丝胶分子量 2 0kD以下。蚕丝在高温高压水或高温高压尿素溶液中的脱胶率都随着处理温度和压力的增大而提高 ,而回收的丝胶蛋白分子量随着处理温度和压力的增大而下降。高温高压水蚕丝脱胶法是一种高效率、低成本、无污染的脱胶方法 ,特别适用于绢纺厂、丝棉厂等蚕丝的脱胶与加工以及纺织厂生丝的精练等。     

铁卜加地区优势种蝗虫发生量与气象因子关系初报

通过对铁卜加地区气象因子与蝗虫发生量的回归分析表明 ,该地区蝗虫发生量与 4～ 5月份的地温极为相关 ,其相关系数Y地温 =0 .95 1