油菜裸苗物理机械特性试验研究

对油菜裸苗茎秆进行物理机械特性试验,包括不同生长期油菜裸苗茎秆截面直径的测定,不同生长期油菜裸苗茎秆的压缩、剪切、拉伸试验。试验研究了油菜裸苗茎秆直径随生长时间的变化规律以及油菜裸苗茎秆压缩、剪切、拉伸极限随生长时间的变化规律,建立了油菜裸苗茎秆截面直径与生长时间的数学模型。研究表明:湘杂1613的油菜裸苗茎秆直径的增长与生长时间呈线性关系;油菜裸苗茎秆的耐压、耐切、耐拉的能力随时间的增加而增加。该结论为设计移栽机械提供了初步的实验基础,同时为进一步研究油菜移栽机械取苗、护苗、栽插参数等关键部件结构和运动学、动力学参数提供了理论依据。     

Post-operative analgesic effects of butorphanol or firocoxib administered to dogs undergoing elective ovariohysterectomy

ObjectiveTo compare the post-operative analgesic effects of butorphanol or firocoxib in dogs undergoing ovariohysterectomy.Study designProspective, randomized, blinded, clinical trial.AnimalsTwenty-five dogs >1 year of age.MethodsDogs received acepromazine intramuscularly (IM), 0.05 mg kg^?1 and either butorphanol IM, 0.2 mg kg^?1 (BG, n = 12) or firocoxib orally (PO), 5 mg kg^?1 (FG, n = 13), approximately 30 minutes before induction of anesthesia with propofol. Anesthesia was maintained with isoflurane. Ovariohysterectomy was performed by the same surgeon. Pain scores using the dynamic and interactive visual analog scale (DIVAS) were performed before and at 1, 2, 3, 4, 6, 8 and 20 hours after the end of surgery by one observer, blinded to the treatment. Rescue analgesia was provided with morphine (0.5 mg kg^?1) IM and firocoxib, 5 mg kg^?1 (BG only) PO if DIVAS > 50. Groups were compared using paired t-tests and Fisher’s exact test (p < 0.05). Data are presented as mean ± SD.ResultsThe BG required significantly less propofol (BG: 2.6 ± 0.59 mg kg^?1; FG: 5.39 ± 0.7 mg kg^?1) (p < 0.05) but the anesthesia time was longer (BG: 14 ± 6, FG: 10 ± 4 minutes). There were no differences for body weight (BG: 7.9 ± 5.0, FG: 11.5 ± 4.6 kg), sedation scores, and surgery and extubation times (BG: 10 ± 2, 8 ± 5 minutes; FG: 9 ± 3, 8 ± 4 minutes, respectively) (p > 0.05). The FG had significantly lower pain scores than the BG at 1, 2 and 3 hours following surgery (p < 0.05). Rescue analgesia was administered to 11/12 (92%) and 2/13 (15%) dogs in the BG and FG, respectively (p < 0.05).Conclusion and clinical relevanceFirocoxib produced better post-operative analgesia than butorphanol. Firocoxib may be used as part of a multimodal analgesia protocol but may not be effective as a sole analgesic.     

Metabolic acidosis in healthy mules under general anaesthesia with halothane

ObjectiveTo report the severe metabolic acidosis identified in a group of 11 healthy mules anaesthetized with halothane for castration.Study designData generated from a prospective study.AnimalsEleven mules aged 2.5–8 years, weighing 230–315 kg and 11 horses aged 1.5–3.5 years, weighing 315–480 kg.MethodsAnimals were anaesthetized for castration as part of an electroencephalographic study. Preanaesthetic medication was acepromazine (0.03 mg kg^?1) administered through a preplaced jugular venous catheter. Anaesthesia was induced 30–90 minutes later with intravenous thiopental (10 mg kg^?1). After orotracheal intubation, anaesthesia was maintained with halothane vaporised in oxygen. The animals’ lungs were ventilated to maintain the end-tidal CO₂ concentration between 3.9 and 4.5 kPa (29–34 mmHg). Anaesthetic monitoring included invasive blood pressure measurement via the auricular artery (mules) and submandibular branch of the facial artery (horses). Arterial blood gas samples were drawn from these catheters at three time points during surgery and pH, PaCO₂, base excess (ecf) and HCO₃^? were measured. Values were compared between groups using a Mann–Whitney test. p was taken as <0.05. Results are reported as median (range).ResultsPaCO₂ did not differ between groups but pH was significantly lower in mules [7.178 (7.00–7.29)] compared to horses [7.367 (7.24–7.43)] (p = 0.0002). HCO₃^? values were significantly lower in the mules [16.6 (13.0–22.3) mM] compared to horses [23.7 (20.9–23.7) mM] (p = 0.0001), whilst base excess (ecf) was significantly more negative in the mules [?11.4 (?1.27 to ?16) mM] compared to horses [?1.3 (?5.8 to +2.4) mM] (p = 0.0004).Conclusion and clinical relevanceThis study demonstrated severe metabolic acidosis in healthy mules, which may have prompted intervention with drug therapies in a clinical arena. It is probable that the acidosis existed prior to anaesthesia and caused by diet, but other possible causes are considered.     

西瓜果形基因图位克隆及分子标记开发

【目的】基于GBS（Genotyping-by-sequencing）高密度遗传图谱初步定位结果,通过图位克隆方法对西瓜果形基因进行精细定位,并开发功能性分子标记,有助于全面研究果形基因的功能及分子标记辅助选择育种。【方法】利用114份纯合西瓜品系全基因组重测序数据及其果形指数表型进行GWAS（genome-wide association study）分析,结合GBS高密度遗传图谱初步定位结果确定果形基因候选区段,以商业小型西瓜品种纯化所得品系K2（椭圆形、FSI=1.54±0.13）和L1（圆形、FSI=1.11±0.07）为材料构建F₂群体,通过开发分子标记对果形基因ClFSI进行精细定位,根据西瓜参考基因组‘97103’v1注释信息确定候选基因,并通过实时荧光定量PCR（qRT-PCR）进行验证。【结果】利用1 152份F₂群体,最终将ClFSI精细定位于3号染色体的FMFSI-1与FMFSI-2标记之间物理距离约63 kb区间内,共包含5个注释基因。其中Cla011257属于已报道与控制果实纵径和果形相关的SUN基因家族。经测序分析发现,西瓜椭圆形品系K2在该基因第3外显子上存在两个非同义突变位点Chr3：26846636 G-A和Chr3：26847041 G-A（‘97103’v1）,分别导致天冬酰胺（Asn）替换为天冬氨酸（Asp）和谷氨酸（Glu）替换为赖氨酸（Lys）,并利用Chr3：26847041突变位点开发功能性分子标记FSICAPS-2。qRT-PCR分析表明,K2（椭圆形）与Charleston Gray（细长形）中候选基因表达量无显著性差异,但均显著高于L1（圆形）。【结论】本研究将控制西瓜果形的ClFSI精细定位于3号染色体63 kb区间内,推测Cla011257为最终目的基因,Chr3：26847041和Chr3：26846636突变位点是导致果形不同程度伸长的重要位点,并开发了可以同时鉴定Cla011257多种突变类型的功能标记FSICAPS-2。     

Cassava common mosaic virus infection causes alterations in chloroplast ultrastructure,function, and carbohydrate metabolism of cassava plants

Cassava common mosaic virus (CsCMV) is a potexvirus that causes systemic infections in cassava plants, leading to chlorotic mosaic and producing significant yield losses. To date, the physiological alterations and the mechanism underlying biotic stress during the cassava–CsCMV compatible interaction remains unknown. In this study, we found that CsCMV infection adversely modified chloroplast structure and had functional effects on chloroplasts in source leaves during the course of viral infection. Extrusion of the chloroplast membrane with amoeboid-shaped appearance and disorganized grana stacks were observed in infected mesophyll cells. These alterations were associated with up to 35% reduction of relative chlorophyll content, and a decline of CO₂ fixation (13.5% and 24.2% at 90 and 210 days after planting, respectively). The effects of CsCMV infection on the performance index on absorption basis dropped up to 37%. The analysis of chlorophyll a fluorescence showed a progressive loss of both oxygen evolving complex activity and “connectivity” within the tripartite system (core antenna-LHCII-reaction centre). Here, we report the latter phenomenon for the first time in a viral infection. The oxidative stress process was observed in CsCMV-infected plants (20.8% reduction of antioxidant capacity with respect to noninfected plants). Other effects of the pathogen included reduction of starch and maltose content in source leaves, and a significant increase (24.7%) of the sucrose:starch ratio, which indicates an altered pattern of carbon allocation. Our results suggest that CsCMV induces chloroplast distortion associated with progressive chloroplast function loss and diversion of carbon flux in source leaf tissue, leading to the loss of cassava tuber yield.     

甜瓜不定芽发生过程中酶活性分析

以4个品系的甜瓜子叶节为外植体,在附加6-BA 1.0 mg·L-1+IAA 0.6 mg·L-1的MS培养基上诱导不定芽,研究甜瓜不定芽发生过程中SOD、POD和CAT 3种抗氧化酶活性、MDA含量、可溶性蛋白含量以及叶绿素含量的变化。结果表明,在甜瓜不定芽发生过程中,SOD和CAT活性变化与愈伤组织的早期发生及不定芽发育密切相关,其中SOD对愈伤组织的早期发生起关键作用;CAT对不定芽发育及成熟起主导作用;而POD作用不明显。可溶性蛋白质含量变化与甜瓜不定芽的诱导发生密切相关;叶绿素含量变化是甜瓜外植体生长状况的重要体现。     

<Emphasis Type="Italic">Sunflower Chlorotic Mottle Virus</Emphasis> in Compatible Interactions with Sunflower: ROS Generation and Antioxidant Response

Sunflower chlorotic mottle virus (SuCMoV) is a recently described potyvirus that causes systemic infections in sunflower plants leading to chlorotic mottling and important growth reductions and yield losses. Oxidative damage is expressed after symptom development in this host-pathogen combination. The involvement of antioxidant enzyme activities in disease susceptibility was studied in two sunflower lines differing in the intensity and rate of development of SuCMoV infections: L2 is more susceptible than L33. A transient superoxide production peak was detected in leaves of both lines before symptom development. H₂O₂ accumulation increased before symptom expression in infected plants of L33 but in L2 such increase was registered only after symptoms became evident. In healthy plants of both lines, superoxide dismutase (SOD), catalase (CAT) and ascorbate peroxidase (APX) showed similar activity levels. In inoculated plants of line L2, but not in L33, SOD and CAT activities increased significantly before the appearance of symptoms, and APX increases were detected later. A 1 mM SA treatment effectively decreased SuCMoV accumulation in plants of L2 but it did not affect it in L33. This treatment increased H₂O₂ accumulation and prevented the increase in antioxidant enzyme activities in infected plants of L2. It is suggested that increases in antioxidant enzyme activities interrupted the signals generated by the increase in ROS, which may have otherwise triggered defence reactions in the host and thus, resulted in a compatible interaction.     

Propofol compared with propofoVguaiphenesin after detornidine premedication for equine surgery

Anaesthesia using propofol alone and in combination with guaiphenesin, after detomidine premedication, was evaluated for performance of minor surgical procedures (castration and tenotomy) in horses. Twelve male horses were premedicated with 0.015 mg/kg of detomidine intravenously (iv) and divided into two groups of six. One group of horses received 2 mg/kg of propofol iv and the other group received 0.5 mg/kg of propofol mixed with 100 mg/kg of a 7.5% solution of guaiphenesin in saline iv. Induction of anaesthesia was fast and smooth in both groups. All horses were easily intubated immediately afterwards but intubation was easier in the horses which received propofol and guaiphenesin. Heart rate fell by 20% in both groups after detomidine injection, stabilising between 45 and 53 beats/minute during anaesthesia with no difference between the groups. Respiratory depression developed after detomidine injection and was slightly intensified after induction of anaesthesia. Respiratory rate was significantly lower in the propofol group (14 ± 3 breaths/minute) than with propofol/guaiphenesin (19 ± 4 breaths/minute) at five minutes after induction. Anaesthesia induced respiratory acidosis in both groups and hypoxaemia also occurred, but once the horses stood up the arterial blood oxygen partial pressure returned to basal values. Surgical time ranged between 8 and 16 minutes and with the exception of one horse in the propofol/guaiphenesin group the horses did not show signs of pain or discomfort during surgery. Recovery to standing was fast and took 26 ± 2 minutes in the propofol and 29 ± 5 minutes in the propofol/ guaiphenesin group. Most horses stood up at the first attempt with minimal ataxia. These two anaesthetic techniques appear to be useful for minor surgical procedures performed within 16 minutes of induction of anaesthesia.     

Effects of four anaesthetic protocols on the neurological and cardiorespiratory variables of puppies born by caesarean section

Twenty-four bitches which had been in labour for less than 12 hours were randomly divided into four groups of six. They all received 0.5 mg/kg of chlorpromazine intravenously as premedication, followed 15 minutes later by either 8 mg/kg of thiopentone intravenously (group 1), 2 mg/kg of ketamine and 0.5 mg/kg of midazolam intravenously (group 2), 5 mg/kg of propofol intravenously (group 3), or 2.5 mg/kg of 2 per cent lidocaine with adrenaline and 0.625 mg/kg of 0.5 per cent bupivacaine with adrenaline epidurally (group 4). Except for group 4, the bitches were intubated and anaesthesia was maintained with enflurane. The puppies' heart and respiratory rates and their pain, sucking, anogenital, magnum and flexion reflexes were measured as they were removed from the uterus. The puppies' respiratory rate was higher after epidural anaesthesia. In general the puppies' neurological reflexes were most depressed after midazolam/ketamine, followed by thiopentone, propofol and epidural anaesthesia.