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1.
研究驼绒藜属3种植物开花规律、开花日动态、结实率及柱头微形态.结果表明,华北驼绒藜和驼绒藜雄花开花高峰均在上午8:00-10:00,有利于传粉和受精,而北美驼绒藜雄花在中午11:00-13:00达开放高峰,其雌雄花开花高峰期不一致,不利于传粉、受精,从而结实率降低.三者的开花最适温度基本一致,都在20~24℃.三者的雌花均在下午14:00左右达到开放高峰.雌花柱头微形态研究结果表明,华北驼绒藜的柱头有利于接受花粉,而北美驼绒藜的柱头不利于接受花粉.此外,华北驼绒藜与驼绒藜的雌、雄花花期相遇结实率较高,而北美驼绒藜因花期不遇,故导致结实率低.  相似文献   

2.
驼绒藜属3种植物开花习性及雌花柱头微形态研究   总被引:9,自引:0,他引:9  
研究驼绒藜属3种植物开花规律、开花日动态、结实率及柱头微形态。结果表明,华北驼绒藜和驼绒藜雄花开花高峰均在上午8:00~10:00,有利于传粉和受精,而北美驼绒藜雄花在中午11:00~13:00达开放高峰,其雌雄花开花高峰期不一致,不利于传粉、受精,从而降低结实率。三者的开花最适温度基本一致,都在20~24℃。三者的雌花均在下午14:00左右达到开放高峰。雌花柱头微形态研究结果表明,华北驼绒藜的柱头有利于接受花粉,而北美驼绒藜的柱头不利于接受花粉。此外,华北驼绒藜与驼绒藜的雌、雄花花期相遇结实率较高,而北美驼绒藜因花期不遇,故导致结实率低。  相似文献   

3.
所谓龙眼花期的“四怕”,即一怕花期传粉媒介少。龙眼同一株树上的雄、雌花一般交错开放,若花期蜂类、蝇类、蝶类等传粉昆虫少,不利于龙眼传粉受精的正常进行。二怕花期连绵阴雨。龙眼花期在4月中旬至5月下旬,雌花开放期一般集中在5月上旬至中旬,若雌花期遇连绵阴雨,雌花柱头粘性降低,雄花花粉无法散发,不利于传粉和受精。三怕花期害虫发生。龙眼花期对农药较敏感,用杀虫剂防治害虫同时会杀灭传粉昆虫,若此期荔枝蝽、卷叶蛾类、木虱等严重发生,会直接为害花穗,降低着果率。四怕干燥风。花期刮寒风、干燥西北风或“东风赤日”…  相似文献   

4.
大花萱草‘金娃娃’的花器结构和繁育系统观察   总被引:1,自引:0,他引:1  
通过观察,运用杂交指数、花粉/胚珠、花粉及柱头活力、坐果率等指标对大花萱草‘金娃娃’(Hemerocallis hybridus cv.‘Stella de oro’)的花部特征、开花动态及授粉特性等进行研究。在人工栽培条件下,金娃娃萱草5-9月开花,花苔分3~4次抽生,首次开花群体花期32 d,单苔花期9~16 d,单花花期1 d。雄蕊短于花柱,花药与柱头相差2.71 cm,在花朵开放的整个过程中雌、雄蕊的相对位置始终不变。开花前1 d的花粉活力最强,开花前1 d和开花当天的柱头具有较强的可授性。杂交指数为4,花粉/胚珠值为1 164,结合坐果率,可以判断其繁育系统属于兼性异交,部分自交亲和,需要传粉者。特殊的花部结构、缺少传粉者和花期短可能是金娃娃萱草结实率较低的原因。  相似文献   

5.
运用修剪、疏枝、大量元素肥料追施以及微量元素喷施技术处理华北驼绒藜(Ceratoides arborescens),通过测定结实率和种子千粒重探讨管理措施对多年生牧草结实及种子质量的影响.结果表明:雄花现蕾前修剪枝条种子千粒重显著低于对照(P<0.05),结实率差异不显著,雄花现蕾后修剪枝条结实率、千粒重均显著提高(P<0.05);保留5个生殖枝/株和10个生殖枝/株较对照显著提高了结实率和千粒重(P<0.05);施氮肥处理结实率和千粒重均显著高于对照(P<0.05),施钾肥处理结实率与对照差异不明显;追施B肥能显著提高结实率(P<0.05),Mn肥和4种微量元素的混合液显著降低结实率(P<0.05),B,Zn,Mo和Mn肥单独使用均能明显提高种子千粒重(P<0.05),混合使用显著降低千粒重(P<0.05).通过对植株自身资源的调控和外配营养来提高结实和种子质量说明华北驼绒藜结实存在资源的限制,适当疏枝使华北驼绒藜侧枝数、结实率和种子千粒重发生超补偿生长,在长期的进化过程中华北驼绒藜可以根据资源的有效性,在结实率和个体大小之间权衡,调整资源分配,确保最大的生殖适合度,具有复杂的繁殖对策.  相似文献   

6.
为了探讨传粉媒介及不同授粉处理对薄壳山核桃结实情况的影响,以环江县岩溶山区引种薄壳山核桃‘Shaoxing’为试验对象,在‘Shaoxing’盛花期对雄花进行不同方位采样,对风媒、虫媒两种传粉方式进行观察,并对雌花进行不同授粉处理。结果表明,‘Shaoxing’在环江县岩溶山区传粉媒介以风媒传粉为主,传粉效率受雄花散粉时期、温度和风向等影响;散粉期有黑带食蚜蝇、中华蜜蜂、黄守瓜、黑胸兼食瓢虫等昆虫访花,对‘Shaoxing’传粉具有辅助作用。除套袋处理组外,不同授粉处理的雌花柱头上的花粉萌发和花粉管生长情况基本相同,不同授粉处理均存在花粉管能穿过花柱但不能到达胚囊完成受精的情况而影响坐果。不同授粉处理中自然授粉处理组的坐果率和结实率均为最高,分别达62.5%和 35%,表明人工辅助授粉对‘Shaoxing’坐果和结实无促进作用,其中套袋处理的结实率为2.06%,说明其可能存在无融合生殖现象;各授粉处理的结实率远远低于坐果率,坐果后仍存在较高的落果率,其中人工自花授粉的坐果后落果率最高,自然授粉的最低,分别为53.61%、27.5%。  相似文献   

7.
紫花地丁花形态的季节转化对繁育系统及结实的影响   总被引:1,自引:0,他引:1  
孙慧芳  魏岩  闫紫烟  严成 《草业学报》2020,29(12):198-204
紫花地丁是一种观赏性状优良的园林草本种质资源。本研究以紫花地丁为研究对象,观测并分析不同花形态对花期物候、花部特征和繁育系统的影响。结果表明:1)紫花地丁具有两种不同形态的花,春季花为开放花,有彩色花冠且花瓣5枚,花萼5枚;花期在4月中到下旬,花期较短,表现为集中开花模式。生于夏秋季的花无花瓣,花萼包裹雌雄蕊,为闭锁花;花期在5月初到9月初,表现为持续开花模式。2)开放花每单花平均有花粉粒7053个,P/O值为173.32~204.49。闭锁花每单花平均花粉粒179.2个,P/O值为4.46~5.95。结合杂交指数表明开放花的繁育系统为异交,部分亲和,需传粉者,而闭锁花为严格的闭花受精。3)开放花花柱具膝曲结构,下方2枚雄蕊背基部有明显的蜜腺体并伸入花瓣形成的距。蜂类传粉者通过碰撞花柱挤压柱头,推动雄蕊距状下臂做杠杆运动进行传粉,从而促进药隔附属物裂开。闭锁花属于严格的闭花受精,不需要传粉媒介。4)闭锁花的单株结实率及结籽率显著高于开放花。  相似文献   

8.
 对五节芒与荻种间人工杂交种群体的开花物候、花粉育性、结实率和花粉母细胞减数分裂行为进行了观察,结果表明,1)F 植株群体和个体花期持续时间长,从6月上中旬至10月中下旬,个体之间花期具很高同步性;通过对抽穗开花分蘖数的统计分析,在杂交种的持续开花过程中,可以将群体和个体的花期分为2个开花高峰,第1次开花高峰出现在6月,第2个开花高峰期出现在9月;从孕穗期和始花期的时间看,杂交种66.07% 的个体的花期偏向于早花的荻亲本,31.25%的个体的花期与亲本五节芒相近,只有2.68%的花期晚于五节芒,说明早花性状的遗传力高;开花物候指数与结实率之间的相关分析结果表明,始花时间与结实率呈负相关关系,开花数和花期持续时间与结实率呈正相关关系。2)亲本荻和五节芒花粉育性较高,可育花粉率显著高于F 群体植株;F 群体2次开花高峰的花粉育性分别为(50.79±18.61)%,(65.42±14.71)%,第2次开花高峰时的花粉育性比第1次开花高峰时高;花粉育性在杂交种群体个体间有较大的差异,平均变异系数为29.56%;花粉育性与结实率的关系不密切,相关系数低,未达到显著性水平。3)种间杂交种F 的花粉母细胞减数分裂基本正常,只有少部分的花粉母细胞出现染色体的异常行为,各时期异常行为率均低于2.0%。本试验结果说明五节芒和荻有很近的亲缘关系,开花物候和生殖特性的研究数据表明杂交种进行进一步遗传改良不存在障碍。  相似文献   

9.
为明确耐热型西番莲品种‘钦蜜9号’花器官发育进程特性和繁育系统类型,测定其花器官表型性状、花粉活性、柱头可授性、杂交指数和花粉/胚珠比。结果发现,‘钦蜜9号’花器官发育进程可分为:现蕾期-花冠发育期-雌雄蕊发育期-裂蕾期-开花授粉期-谢花期,时间持续25-27d,开花时间为下午13︰00-15︰00,单花开放时长约24 h,开花前3 d左右(花药即将开裂时)至裂蕾时柱头可授性最强;花粉数量为7.94x105个/花药,活性为90.11%,繁育系统类型为异交型,自交亲和,异交需要传粉者。这些特征为‘钦蜜9号’在35℃以上高温还能正常开花并结实提供了重要的基础条件。  相似文献   

10.
西卡柱花草传粉受精过程花朵形态变化的研究   总被引:2,自引:0,他引:2  
罗丽娟  刘国道 《草地学报》1999,7(2):136-141
对西卡柱花草传粉受精过程花朵形态变化的研究结果表明,凌蛄3~6时,多数花蕾进行自花授粉,6~7时,花蕾完成自花授粉过程,此时萼管与花冠长度几乎相等。上竿8:30~9:30,小花开放但龙骨瓣仍闭合时,花粉粒在柱头上萌发。开共经骨瓣松开,露出雌雄蕊,花粉管穿过花柱道、子房内壁进入胚珠。花后6小时左右,小花关闭,合子及初生胚乳核中出现雄性核仁。小花开放过程中的形态变化可作为传粉、花粉萌发、受精作用的形态  相似文献   

11.
试验选用96头平均体重14.82 kg左右的杜×长×大断奶仔猪,随机分成4组,每组3栏,每栏8头(公母各半)。对照组饲喂基础日粮,试验1、2、3组分别添加1%80目白术、0.2%白术多糖和1%微米白术。试验期30 d。结果表明:在生长性能方面,与对照组相比,1%微米白术添加组可显著提高日增重(P0.05)、降低饲料增重比和腹泻率,而且效果优于1%80目白术组和0.2%白术多糖组,在肠道形态和肠道微生态区系方面,与对照组相比,日粮添加1%80目白术、0.2%白术多糖、1%微米白术均可不同程度的提高十二指肠和空肠的绒毛高度,加深十二指肠和空肠的隐窝深度,并且增加肠道微生态区系的多样性,其中以1%微米白术添加组的效果最佳。  相似文献   

12.
Sissay, M.M., Uggla, A. and Waller, P.J., XXXX. Prevalence and seasonal incidence of nematode parasites and fluke infections of sheep and goats in eastern Ethiopia. Tropical Animal Health and Production, XXXX. A 2-year abattoir survey was carried out to determine the prevalence, abundance and seasonal incidence of gastro-intestinal (GI) nematodes and trematodes (flukes) of sheep and goats in the semi-arid zone of eastern Ethiopia. During May 2003 to April 2005, viscera including liver, lungs and GI tracts were collected from 655 sheep and 632 goats slaughtered at 4 abattoirs located in the towns of Haramaya, Harar, Dire Dawa and Jijiga in eastern Ethiopia. All animals were raised in the farming areas located within the community boundaries for each town. Collected materials were transported within 24 h to the parasitology laboratory of Haramaya University for immediate processing. Thirteen species belonging to 9 genera of GI nematodes (Haemonchus contortus, Trichostrongylus axei, T. colubriformis, T. vitrinus, Nematodirus filicollis, N. spathiger, Oesophagostomum columbianum, O. venulosum, Strongyloides papillosus, Bunostomum trigonocephalum, Trichuris ovis, Cooperia curticei and Chabertia ovina), and 4 species belonging to 3 genera of trematodes (Fasciola hepatica, F. gigantica, Paramphistomum {Calicohoron} microbothrium and Dicrocoelium dendriticum) were recorded in both sheep and goats. All animals in this investigation were infected with multiple species to varying degrees. The mean burdens of adult nematodes were generally moderate in both sheep and goats and showed patterns of seasonal abundance that corresponded with the bi-modal annual rainfall pattern, with highest burdens around the middle of the rainy season. In both sheep and goats there were significant differences in the mean worm burdens and abundance of the different nematode species between the four geographic locations, with worm burdens in the Haramaya and Harar areas greater than those observed in the Dire Dawa and Jijiga locations. Similar seasonal variations were also observed in the prevalence of flukes. But there were no significant differences in the prevalence of each fluke species between the four locations. Overall, the results showed that Haemonchus, Trichostrongylus, Nematodirus, Oesophagostomum, Fasciola and Paramphistomum species were the most abundant helminth parasites of sheep and goats in eastern Ethiopia.  相似文献   

13.
14.
1-(2-Chloroethyl)3-cyclohexyl-1-nitrosourea (CCNU) is an alkylating agent in the nitrosourea subclass. A prospective evaluation of CCNU was done to determine the maximally tolerated dosage of CCNU in tumor-bearing cats. Response data were obtained when available. Twenty-five cats were treated with CCNU at a dosage of 50-60 mg/m3 body surface area. Complete hematologic data were available for 13 cats. Neutropenia was the acute dose-limiting toxicity. The median neutrophil count at the nadir was 1,000 cells/microL (mean, 2,433 cells/microL; range, 0-9,694 cells/microL). The time of neutrophil nadir was variable, occurring 7-28 days after treatment, and counts sometimes did not return to normal for up to 14 days after the nadir. Based on these findings, a 6-week dosing interval and weekly hematologic monitoring after the 1st treatment with CCNU are recommended. The nadir of the platelet count may occur 14-21 days after treatment. The median platelet count at the nadir was 43,500 cells/microL. No gastrointestinal, renal, or hepatic toxicities were observed after a single CCNU treatment, and additional studies to evaluate the potential for cumulative toxicity should be performed. Five cats with lymphoma and 1 cat with mast cell tumor had measurable responses to CCNU. Phase II studies to evaluate antitumor activity should be completed with a dosing regimen of 50-60 mg/m3 every 6 weeks.  相似文献   

15.
Our particular attention in this article was given to natural mediators for macrophages isolated from the sites of tissue injury. A number of chemotactic factors, which may satisfy many criteria making them acceptable as inflammatory leucocyte chemotactic factors, has been separated. Among them, our laboratory has isolated three macrophage (monocyte) chemotactic factors (MCF-a, -b and -c). Their purification, characterization and functional specificity are discussed.  相似文献   

16.
Continuous rate infusion (CRI) of furosemide in humans is considered superior to intermittent administration (IA). This study examined whether furosemide CRI, compared with IA, would increase diuretic efficacy with decreased fluid and electrolyte fluctuations and activation of the renin-angiotensin-aldosterone system (RAAS) in the horse. Five mares were used in a crossover-design study. During a 24-hour period, each horse received a total of 3 mg/kg furosemide by either CRI (0.12 mg/kg/h preceded by a loading dose of 0.12 mg/kg IV) or IA (1 mg/kg IV q8h). There was not a statistically significant difference in urine volume over 24 hours between methods; however, urine volume was significantly greater after CRI compared with IA during the first 8 hours ([median 25th percentile, 75th percentile]: 9.6 L [8.9, 14.4] for CRI versus 5.9 L [5.3, 6.0] for IA). CRI produced a more uniform urine flow, decreased fluctuations in plasma volume, and suppressed renal concentrating ability throughout the infusion period. Potassium, Ca, and Cl excretion was greater during CRI than IA (1,133 mmol [1.110, 1,229] versus 764 mmol [709, 904], 102.7 mmol [96.0, 117.2] versus 73.3 mmol [65.0, 73.5], and 1,776 mmol [1,657, 2.378] versus 1,596 mmol [1,457, 1,767], respectively). Elimination half-lives of furosemide were 1.35 and 0.47 hours for CRI and IA, respectively. The area under the excretion rate curve was 1,285.7 and 184.2 mL x mg/mL for CRI and IA, respectively. Furosemide CRI (0.12 mg/kg/h) for 8 hours, preceded by a loading dose (0.12 mg/kg), is recommended when profound diuresis is needed acutely in horses.  相似文献   

17.
Genetic variations in chromosome Y are enabling researchers to identify paternal lineages, which are informative for introgressions and migrations. In this study, the male‐specific region markers, sex‐determining region‐Y (SRY), amelogenin (AMELY) and zinc finger (ZFY) were analysed in seven Turkish native goat breeds, Angora, Kilis, Hair, Honaml?, Norduz, Gürcü and Abaza. A SNP in the ZFY gene defined a new haplotype Y2C. All domestic haplogroups originate from Capra aegagrus, while the finding of Y1A, Y1B, Y2A and Y2C in 32, 4, 126 and 2 Turkish domestic goats, respectively, appears to indicate a predomestic origin of the major haplotypes. The occurrence of four haplotypes in the Hair goat and, in contrast, a frequency of 96% of Y1A in the Kilis breed illustrate that Y‐chromosomal variants have a more breed‐dependent distribution than mitochondrial or autosomal DNA. This probably reflects male founder effects, but a role in adaptation cannot be excluded.  相似文献   

18.
The objective of this report was to characterize 20-year changes in proportion of calcium oxalate (CaOx) calculi and struvite calculi in dogs, and associations with breed, age, and sex. In this retrospective study, results of analysis of urinary calculi from dogs were reviewed for specimens received between July 1, 1981, and December 31, 2001. Breed, sex, age, year of submission of the specimen, and mineral type(s) were analyzed statistically. CaOx or Struvite or both were contained in 18,966 of 20,884 (91%) specimens. For both sexes, a 20-year statistically significant increase was observed in the proportion of calculus specimens that contained CaOx. The increase in this proportion was greater in females (1% to 31%) than in males (18% to 82%). From 1998 to 2001, when proportions may have plateaued, the odds of specimens containing CaOx were markedly higher in 18 breeds, markedly lower in 5 breeds, and not significantly different in 13 breeds compared with crossbreds. For both sexes, a 20-year statistically significant decrease was observed in the proportion of calculus specimens that contained struvite. This decrease in proportion was greater for males (79-16%) than for females (97-68%). From 1998 to 2001, when proportions plateaued, the odds of calculi containing struvite were markedly lower in 20 breeds, markedly higher in 1 breed, and not significantly different in 15 breeds when compared with crossbreds. Breed, age, and sex were associated statistically with CaOx or struvite urolithiasis. In conclusion, there appears to have been a long-term increase in the proportion of specimens of canine urinary calculi that contain CaOx as well as a long-term decrease in the proportion of specimens of calculi that contain struvite for both male and female dogs. The rate of change appeared to begin leveling off in the period 1998 to 2001. The recent proportion of dogs with either CaOx- or struvite-associated urolithiasis may depend on breed, age, and sex, and on interactions among these 3 factors.  相似文献   

19.
<正>1.INTRODUCTION Ensuring transportation network security is one Of the most daunting challenges confronting homeland security agencies today.Significant research has been dedicated.To model and analyze the vulnerability of transportation systems,while notably fewer studies propose specific strategies for deploying defensive technologies to safeguard these systems.  相似文献   

20.
The epidemiology of H. placei and of other gastrointestinal nematodes in yearling dairy cattle was examined on two farms in Kiambu District, central Kenya during each of 13 one-month periods from April 1993 to April 1994. On each farm, 32 newly weaned dairy calves were given a single dose of albendazole and then placed on experimental pastures. Twelve of the animals were designated for bi-monthly slaughter (n = 2) and analysis of worm population characteristics and 20 were designated for blood and faecal collection and for weighing. Two parasite-free tracer calves were grazed alongside the weaner calves each month throughout the study period and were also slaughtered for analysis of worm populations. Faecal egg counts, haematological and serum pepsinogen determinations, herbage larval counts, and animal live weight changes were recorded monthly. The study revealed that Haemonchus placei, Trichostrongylus axei, Cooperia spp. and Oesophagostomum radiatum were responsible for parasitic gastroenteritis and that H. placei was the predominant nematode present in the young cattle on both farms. Faecal egg counts from resident cattle and necropsy worm counts revealed that pasture larval levels were directly related to the amount of rainfall. The total worm burdens in the animals were highest during the rainy season (March–June and October–December) and lowest during the dry seasons (July–September and January–February). The very low recovery of immature larvae of H. placei from the tracer calves indicated that arrested development is not a feature of the life cycle of this parasite in central Kenya. The maintenance of the parasite population depended on continuous cycling of infection between the host and the pasture. The agroclimatic conditions of the study area were such that, in general, favourable weather conditions for the development and survival of the free-living stages of gastrointestinal nematodes existed all year round.  相似文献   

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