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81.
肉鸡和蛋鸡心肌易颤性的比较研究 总被引:1,自引:0,他引:1
以常规饲养的肉鸡和蛋鸡作为试验动物,通过电刺激诱颤阈和输钾诱颤阈的测定以及进行冷加压试验,对同体重肉鸡和蛋鸡的心肌易颤性进行了比较研究。结果表明:(1)同体重肉鸡和蛋鸡相比,电刺激诱颤阈和输钾诱颤阈肉鸡均极显著低于蛋鸡(P<0.01);(2)在电刺激诱发室颤的过程中,开胸时室颤的发生率肉鸡(14%)显著高于蛋鸡(0%)(P<0.05);(3)冷加压试验:冷加压5min内,心率和PT波宽出现了显著的变化,而且变化幅度肉鸡均明显大于蛋鸡。上述试验结果从不同方面均表明肉鸡心肌易颤性高于蛋鸡。 相似文献
82.
Thomas Miedaner Angela G. Schilling Geiger 《European journal of plant pathology / European Foundation for Plant Pathology》2004,110(1):63-70
Fusarium culmorum is a phytopathogenic, toxigenic fungus causing seedling diseases, foot rot and head blight of cereals. For estimating competition effects in mixtures of two single-spore isolates, two winter rye single crosses were tested with either four isolates individually or four 1 : 1 mixtures of the same isolates in six field environments. Two isolates (FC46, FC64) were highly aggressive deoxynivalenol (DON) and 3-acetyl DON-producers, the other two (FC30, FC71) were medium aggressive nivalenol-producers. Rye heads were inoculated during flowering with conidia of pairs of isolates expressing similar (FC46 + FC64, FC30 + FC71) or contrary (FC46 + FC71, FC30 + FC64) levels of aggressiveness and similar or different concentrations and chemotypes of mycotoxins, respectively. Head blight rating and yield components relative to the non-inoculated plots were recorded as aggressiveness traits. Additionally, mycotoxin concentrations were measured in the rye grain. Random pathogen samples were re-isolated from heads at the onset of symptom development and analysed by molecular markers (RAPD–PCR) in one environment. Aggressiveness of the isolate mixtures was significantly lower than that of the isolates applied individually on both rye genotypes. Similarly, mycotoxin concentrations were significantly lower in the mixtures in seven out of eleven comparisons. Among the re-isolates, the component genotypes of a mixture significantly deviated from the inoculated 1 : 1 ratio when a particular isolate (FC46) was present in the mixture. This isolate displayed a superior competitive ability irrespective of the aggressiveness or mycotoxin profile of the mixing partner illustrating that pathogenic fitness is caused by additional factors that have not, as yet, been identified. 相似文献
83.
几种牧草对河西走廊盐渍化土壤改土培肥的效应研究 总被引:13,自引:2,他引:13
在河西走廊盐渍化土地上种植老芒麦、扁穗冰草、碱茅和紫花苜蓿4种优质牧草,对盐渍化程度均有一定的改良效果.其中碱茅对盐渍化土壤的改土培肥效果最好,建植3年后的碱茅,与对照比较,0~20 cm土层中自然含水量增加125.99 g/kg,总孔度增加16.14%,容重降低0.27 g/cm3,pH值由8.43降到8.10,全盐含量降低52.90 g/kg,脱盐率达到76.12%,有机质增加3.67 g/kg,碱解氮含量增加18.63 mg/kg,速效磷和钾亦随之增加. 相似文献
84.
85.
血清1、2、4、5型鸭疫里默氏杆菌的RAPD 总被引:2,自引:0,他引:2
以37℃摇震培养舜口烛缸厌氧培养,从12种培养基中选择出鸭疫里默氏杆茼的最优培养基和培养条件。以血清1、2、4、5型的鸭疫里默氏杆菌代表株A1、A2、A3、A4为研究对象,培养增殖后分别提取基因组DNA,利用随机扩增多态性DNA(RAPD)技术,对其基因组进行了DNA分析。从20条随机引物中筛选出8条随机引物,这8条引物对4种血清型的鸭疫里默氏杆菌的扩增图谱有较好的多态性,可作为分子标记鉴别4种不同血清型的鸭疫里默氏杆菌,同时还筛选出能在4个血清型的鸭疫里默氏杆菌代表株均出现相同的特征条带,而对照茼大肠杆菌、沙门氏茼无该条带的随机引物,从而为鸭疫里默氏杆菌病的分子诊断打下了一定基础。 相似文献
86.
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89.
植物的花序结构及其形态特征是影响种子生产性能的重要因素。对于禾本科植物而言,其花序大小、小穗数、小花数及小花的外稃、内稃和芒的性状特征直接影响种子形成和产量。本研究通过测定小黑麦品系C2、C35和黑麦品系C13、C33的花序结构特征,得到以下结果:小黑麦花序[(14.30±0.52) cm×(1.24±0.09) cm]明显大于黑麦[(13.20±0.35) cm×(0.82±0.02) cm],小黑麦花序长而粗,黑麦花序短而细;小黑麦花序的小穗数[(21.35±1.47)个]少于黑麦[(30.20±0.79)个];小黑麦每个小穗的小花数较多,为3~4朵,黑麦的小花数趋于稳定,每个小穗有2朵小花。从花序中部小穗的小花结构看,小黑麦下位护颖长[(1.27±0.11) cm]和宽[(0.26±0.03) cm]、上位护颖长[(1.30±0.09) cm]和宽[(0.23±0.04) cm]均显著大于黑麦下位护颖长[(1.04±0.05) cm]和宽[(0.08±0.01) cm]、上位护颖长[(0.94±0.10) cm]和宽[(0.06±0.01) cm];小黑麦中部小穗第1小花的外稃宽[(0.32±0.03) cm]、外稃高[(0.24±0.03) cm]和芒长[(8.35±0.51) cm]、第2小花的外稃宽[(0.35±0.04) cm]、外稃高[(0.25±0.05) cm]和芒长[(8.37±1.19) cm]极显著大于黑麦相应值[(0.26±0.01),(0.15±0.01),(5.50±0.19),(0.25±0.01),(0.17±0.01)和(5.18±0.23) cm];第1和第2小花的外稃长[(1.35±0.06),(1.37±0.06) cm]和内稃长[(0.84±0.04),(1.41±0.06) cm]均小于黑麦的外稃长[(1.49±0.05),(1.47±0.05) cm]和内稃长[(1.45±0.05),(1.47±0.04) cm]。小黑麦的穗粒数[(52.50±1.80)粒]显著低于黑麦[(58.50±2.50)粒] (P<0.05),但其穗粒重[(2.08±0.04) g]、粒重[(0.04±0.00) g]和籽粒宽[(3.04±0.32) mm]均极显著高于黑麦 (P<0.01),每个花序的籽粒不仅体积大,而且质量较重,其籽粒的生产性能高于黑麦。小黑麦籽粒呈椭圆形或长卵圆形,浅黄色,表皮皱缩,饱满度差;黑麦籽粒呈窄纺锤形,青灰色,表皮光滑,籽粒饱满。小黑麦和黑麦花序结构与籽粒性状的Pearson相关分析表明,小黑麦花序宽和花序基部小穗数与籽粒长显著正相关(P<0.05),花序长与籽粒宽极显著正相关(P<0.01),花序中部小穗的下、上位护颖宽分别与穗粒重和穗粒数极显著正相关(P<0.01);黑麦花序中部小穗第2小花的内稃长与籽粒长显著正相关(P<0.05),外稃高与穗粒数极显著负相关(P<0.01)。研究小黑麦和黑麦的花序结构和籽粒特征,对正确区分二者和了解其籽粒的生产性能具有重要意义,同时有利于小黑麦的示范推广。 相似文献
90.
Yield Performance of Wheat Isolines with Different Dosages of the Short Arm of Rye Chromosome 1
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Translocations of the short arm of rye (Secale cereale L.) chromosome 1 (1RS) in wheat (Triticum aestivum L. cv. Pavon 76) are known to increase root biomass. Such an increase enhances water and nutrient uptake and may improve grain yield. Two greenhouse experiments and a field experiment were carried out at the University of California, Riverside, in 2012 and 2013 under well‐watered and terminal drought treatments to evaluate phenotypic characters associated with varying dosages of 1RS, including grain yield. The genotypes used were cultivar Pavon 76 (R0), Pavon 76/Pavon1RS.1AL (F1 hybrid) with a single dosage of 1RS (R1A), Pavon 1RS.1AL with two dosages of 1RS (R2A), Pavon 1RS.1DL (R2D) also with two dosages of 1RS and Pavon 1RS.1AL‐1RS.1DL (R4AD) with four dosages of 1RS. There was a significant positive correlation between number of dosages of 1RS and root biomass. However, no correlation was found between root biomass and grain yield per plant. Drought in the field experiment reduced grain yield significantly. Under well‐watered field conditions, grain yield of R2A (215.9 g plant?1) was significantly greater than those of R2D (191.8 g plant?1) and R4AD (161.7 g plant?1). Also, grain yield of R4AD was significantly less than those of F1, Pavon 76 and R2D under well‐watered conditions. Under drought field conditions, no significant differences were found among the genotypes for grain yield was found between F1 (14.7 g plant?1) and R4AD (12.4 g plant?1). Harvest index was significantly greater in well‐watered (44.2 %) than in drought (34.6 %) field conditions. On average, genotypes F1 (42.3 %) and R2A (40.6 %) had higher harvest index than R2D (38.3 %) and R4AD (35.5 %) in the field. Also, Pavon 76 (40.2) and R2D (38.3) had higher harvest index than R4AD. Drought tolerance was lowest for R4AD due to its relatively lower grain yield potential. In general, Pavon 1RS.1AL carrying two dosages of 1RS showed higher grain yield under wet treatments. Pavon 1RS.1AL‐1RS.1DL carrying four dosages of 1RS produced the largest shoot and root biomasses, but the least grain yield. 相似文献