Effects of Climatic Factors Prevailing Prior to Flowering or Subsequent to Boll Setting on Flower and Boll Production and Retention of Cotton in Egypt

This study was conducted to investigate the nature of the effects of climatic factors prevailing prior to flowering or subsequent to boll setting on flower and boll production and retention in Egyptian cotton (Gossypium barbadense L.). Two uniform field trials, using the cotton cv. Giza 75, were carried out in 1992 and 1993 at the Agricultural Research Centre, Giza, Egypt. Randomly chosen plants were used to record daily numbers of flowers and bolls during the production stage (68 days in the first season and 62 days in the second season). The daily records of the climatic factors (air temperature, temperature magnitude, evaporation, surface soil temperature, sunshine duration and humidity) were recorded during the entire period of production and the 15 days preceding or succeeding flower opening. The effects of climatic factors on flower and boll production were quantified in non‐limiting management techniques. Relationships in the form of simple and multiple correlations were computed between climatic factors and flower and boll production and retention. The data indicate that evaporation, minimum humidity and sunshine duration were the most effective climatic factors during preceding and succeeding periods on fruit production and retention. The relationship between climatic factors preceding flowering and cotton production generally exceeded the relationship between the factors during the entire and latter periods of production stage. The result was a negative correlation between either evaporation or sunshine duration with flower and boll formation. In addition, a positive correlation was evident between minimum humidity and flower and boll production. The data indicate that low evaporation rate, reduced sunshine duration and high humidity would enhance flower and boll formation. Accordingly, the deleterious effects of climatic factors on cotton production could be minimized through applying appropriate production practices, which would control and adjust the impact of these factors, and this could lead to an important improvement in cotton yield in Egypt.     

猫跳河流域气象水文因素的变化趋势分析

以我国第一条全流域梯级水电开发的河流猫跳河为对象,系统分析了猫跳河流域主要气象水文变量的基本情势,分析了各因素的变化趋势。利用紧邻猫跳河流域的贵阳、安顺和黔西地区的3个气象站近60a的逐日气象观测数据,采用线性回归和Mann-Kendall法检测其变化趋势,利用FAO56方法计算了流域参考作物的蒸散发状况。结果表明:(1)流域多年平均降水量在1 000～1 300mm之间,没有显著的变化趋势;(2)在过去60a,流域平均气温累计上升约0.4～1.0℃,呈现一定程度的暖化趋势;(3)流域的平均年日照时数在1 200～1 300h之间,且呈现明显的下降趋势,大致以8～10h/a的速率递减;(4)流域日参考作物蒸发在2.5～2.7mm/d之间。多年平均参考作物蒸发在900～1 000mm之间。年参考作物蒸发下降趋势显著,与日照时数的减小相一致。猫跳河流域总体上呈现一定程度的暖化现象,但气候变化对水资源的影响程度有限。     

近50年海口市日照时数气候变化特征分析

利用海口市1961～2010年日照时数实测资料,分析年代际、年际和季节的气候变化特征,同时与总云量、低云量、相对湿度和降雨量资料,进行相关分析。结果表明：近50年海口市日照时数呈下降趋势,每10年偏少117.2 h,其中2001～2010比1961～1970 下降了20%以上。海口市日照减少与低云量的增加有密切关系,与夏秋季节的降雨量也有关系。     

Replacement of Fishmeal with a Blend of Poultry Byproduct Meal and Soybean Meal in Diets for Largemouth Bass,Micropterus salmoides

A feeding trial was conducted to evaluate the potential of replacing fishmeal with poultry byproduct meal (PBM) and soybean meal in diets for largemouth bass, Micropterus salmoides. A reference diet (C) contained 400 g/kg fishmeal, and 40 or 60% of the fishmeal was replaced with a blend of pet‐food‐grade PBM and soybean meal (diets PP1 and PP2) or a blend of feed‐grade PBM and soybean meal (diets PF1 and PF2). No significant differences were found in weight gain, nitrogen retention efficiency (NRE), condition factor, and body composition among fish fed diets PP1, PP2, PF1, and PF2. Feed intake and feed conversion ratio (FCR) were higher in fish fed diet PF1 than in fish fed diet PP1. No significant differences were found in weight gain, NRE, condition factor, and body composition between fish fed diet C and diets PP1, PP2, PF1, and PF2. The feed intake and FCR were lower in fish fed diet C than in fish fed diets PP2, PF1, and PF2. This study reveals that dietary fishmeal level for largemouth bass could be reduced to 160 g/kg by inclusion of PBM and soybean meal in combination.     

近35年甘肃庆阳黄土高原地带气候特征分析

通过研究全球气候变化下甘肃庆阳地区气候变化的特点,为黄土高原地带农业及经济的发展提供理论依据。研究利用庆阳市8 站近35 年的降水、气温、日照时数等气象资料,应用多种统计方法分析了庆阳黄土高原地带的区域气候特征及其变化规律。结果表明,甘肃庆阳黄土高原地带降水量季节分配不均,干湿季分明,强降水天气均出现在4—9 月。中部和东南部年降水量呈减少趋势,西北部呈增多趋势;气温差异性则表现为山壑地区比平原和川区冬天气温低,夏天气温高,年平均气温呈升高趋势,且升高趋势冬季贡献显著;年日平均日照时数西北部和中部呈增多趋势,东南部则呈明显减少趋势,4—8月为日照时数高值区,且夏季比冬季日照时数多出约1 h。     

饥饿对大口黑鲈消化器官、蛋白酶和淀粉酶活力的影响

对饥饿和饥饿后投喂的大口黑鲈(Micropterus salmoides)蛋白酶和淀粉酶活力及消化组织的变化进行了研究,饥饿周期为30d。饥饿对大口黑鲈消化道指数的影响为肝体比从试验的第3天开始明显下降(P<0.05),第20天开始保持稳定水平(P>0.05);幽门盲囊重与体重比先上升后下降;胃重与体重比始终呈上升趋势(P<0.05);肠重与体重比在第10天开始保持稳定水平(P>0.05);肠长与体长比呈上升趋势(P<0.05)。饥饿对蛋白酶活力影响为从开始到第3天胃蛋白酶活力上升,第10天开始下降;幽门盲囊蛋白酶活力在第10天之后持续下降(P<0.05);肠道蛋白酶活力一直呈下降趋势。饥饿对淀粉酶活力影响为肝脏淀粉酶活力、胃淀粉酶活力和幽门盲囊淀粉酶活力均呈下降趋势(P<0.05);肠道淀粉酶活力第10天之后即稳定在低水平(P>0.05)。饥饿后摄食对蛋白酶活力和淀粉酶活力的影响为饥饿后摄食蛋白酶活力和淀粉酶活力均呈上升趋势,上升的速度在不同组织有差异,在恢复摄食后的第10天基本达到正常水平。     

不同钾肥用量对日光温室黄瓜生长性状影响初探

在设施条件下,研究了不同钾肥用量对黄瓜生长性状的影响.结果表明,在氮、磷肥适量施用的基础上,随着施钾肥量的增加,黄瓜还原糖和Vc含量及产量增加.通过对不同处理间的差异分析,结果表明,当施钾肥720kg·hm-2时,肥料增产效益最佳.     

大口黑鲈蛙病毒分子流行病学及组织病理分析

为探讨大口黑鲈蛙病毒（LMBV）的分子流行规律及在感染后的组织病理变化，实验对2019—2021年采集的723份患病大口黑鲈样品进行荧光定量PCR （qPCR）检测。结果显示，LMBV的阳性率为63.62%，挑选阳性样品接种鳜脑细胞（Chinese perch brain cells,CPB），共获得93株LMBV。通过对分离株MCP、ATP酶、DNA聚合酶和甲基转移酶基因进行PCR扩增与测序分析，发现上述基因在LMBV分离株中均保守，其中MCP、ATP酶基因一致性均为100.0%、甲基转移酶基因一致性为99.7%～100.0%、DNA聚合酶基因一致性为99.8%～100.0%。选取1株LMBV毒株感染健康大口黑鲈，采用qPCR方法对不同组织中的病毒载量进行检测，结果显示，大口黑鲈蛙病毒在心脏、肝脏、脾脏、肾脏、胃、肠和脑等组织中均有分布，人工感染LMBV后的前5天病毒载量逐步升高；感染后第5天，心脏中病毒载量最高（9.5×10⁵个/mg拷贝），脑组织中病毒载量最低（2.9×10²个/mg拷贝）。组织病理结果表明，LMBV可导致大口黑鲈多种组...     

昭苏县天然草地牧草产量与气象因素的关系研究

为探讨各时间段降雨量、平均温度、日照时数对牧草产量的影响及其定量关系,根据逐月气象数据,将2012—2019年的降雨量、平均气温和日照时数按照时间段分别分成13组,对降雨量、平均温度、日照时数的各组数据与天然草地鲜草产量进行相关性分析及多元回归分析。结果表明：降雨量与鲜草产量的相关性最高,3—7月总降雨量与鲜草产量的正相关性达到了极显著水平（相关系数r=0.839,P=0.009<0.01）,3、4月的降雨量对牧草产量的影响最大。2—7月平均气温与鲜草产量的正相关性达到了极显著水平（相关系数r=0.840,P=0.009<0.01）,2月的平均气温对牧草产量的影响最大。日照时数与鲜草产量的相关性不显著(P>0.05)。多元回归定量分析显示,3—7月的总降雨量每增加1 mm,鲜草产量增加289.693 kg/hm²,2—7月的平均气温每增加0.1℃,鲜草产量增加144.93 kg/hm²。降雨变化对鲜草产量的变化量影响较平均气温的大。     

芽孢杆菌有氧发酵豆粕替代鱼粉对大口黑鲈幼鱼生长性能、血清生化指标及肠组织结构的影响

芽孢杆菌(Bacillus)有氧发酵豆粕的肽类和活菌等含量丰富,为研究其替代鱼粉对大口黑鲈(Micropterus salmoides)幼鱼的养殖效果,配制鱼粉含量为50％的大口黑鲈基础饲料,在基础饲料中用芽孢杆菌有氧发酵豆粕分别替代0、10％、20％、30％和40％的鱼粉,配制成5种等氮、等能实验饲料进饲养实验.实验...