草地早熟禾午夜2号植株再生研究

以草地早熟禾(Poa pratensis L.)品种午夜2号成熟种子为外植体,进行植株再生研究,建立高频再生体系,为草地早熟禾进行原生质体培养和细胞融合奠定基础。结果表明:诱导愈伤组织的最佳培养基为MS+2,4-D(1mg/L)+6-BA(0.1 mg/L)+3%蔗糖+0.7%琼脂,其诱导率为52.3%;最佳继代培养基为MS+2,4-D(1mg/L)+6-BA(0.3mg/L)+3%蔗糖+0.7%琼脂;最佳分化培养基为MS+NAA(0.5 mg/L)+6-BA(1 mg/L)+3%蔗糖+0.6%琼脂、分化率为57.5%;生根培养基同分化培养基,供体材料经100d的培养后获得再生植株。     

岷山红三叶愈伤组织诱导和植株再生研究

通过对岷山红三叶下胚轴和子叶再生体系建立的研究,获得愈伤组织诱导的最佳培养基为:MS+2 mg/L 2,4-D+0.5 mg/L6-BA+2%蔗糖+0.6%琼脂,胚性愈伤组织诱导培养基为:MS+0.1 mg/L IAA+0.5 mg/L 6-BA+2%蔗糖+0.6%琼脂,芽诱导培养基为:B5+0.06 mg/L NAA+2%蔗糖+0.6%琼脂,每瓶可以长出2~10条茎,将茎转入生根培养基后愈伤继代可持续出芽。最佳的生根培养基为:1/2 MS+0.05mg/LNAA+1.5%蔗糖+0.8%琼脂。建立再生植株约需160 d。     

紫花与杂花苜蓿再生影响因子的比较研究

对紫花苜蓿(Medicago sativa L.)(秘鲁、关中、甘农3号)及杂花苜蓿(Medicagovaria Martyn)(甘农1号、甘农2号)组培再生体系各影响因子进行比较研究。结果表明:紫花、杂花苜蓿的组培再生能力差异较大,前者显著高于后者;在愈伤组织诱导中,子叶节是最佳的外植体材料;2,4-D浓度增加对紫花苜蓿出愈率影响不明显,但杂花苜蓿的出愈率随着2,4-D浓度的增加呈明显的升高趋势;紫花苜蓿的最佳愈伤组织诱导培养基为MS₊2,4-D2.0mg/L+蔗糖30g/L,诱导率均在95%以上;杂花苜蓿为MS₊2,4-D 4.0mg/L+蔗糖30 g/L,两个品种诱导率分别为65.6%、73.3%;5个品种的最适分化培养基均为MS₊KT 1.0 mg/L+NAA 0.5mg/L+蔗糖20 g/L或MS₊BA4.0 mg/L,分化率也各有差异,紫花苜蓿不定芽的分化率可达到70%左右,而杂花苜蓿在30%左右;最佳诱导生根的培养基为1/2MS₊IBA 1.0 mg/L;本研究建立了紫花苜蓿高频再生组织培养体系,为实现外源基因的高效遗传转化奠定基础;通过紫花苜蓿和杂花苜蓿的再生体系影响因子的比较研究,为杂花苜蓿再生体系的建立提供参考。     

The application of various picloram formulations to cut stumps of Brachystegia spiciformis Benth., Julbernardia globiflora (Benth.) Troupin,Terminalia sericea Burch. ex DC. and Acacia karroo Hayne trees

Trees were felled 150 mm above ground level and various mixtures of picloram with 2,4‐D araine, 2,4,5‐T amine in water solution or 2,4,5‐T ester in diesel oil were applied to the freshly‐cut surfaces. Mixtures of picloram/2,4‐D amine and picloram/2,4,5‐T amine, both water soluble, gave the highest kill rates when applied to trees in the growing season (October and May). The oil emulsifiable picloram/2,4,5‐T ester formulation tended to be effective throughout the year and high kill rates were frequently obtained with applications made in June or July. Application rates of picloram/2,4‐D amine or picloram/2,4,5‐T amine (expressed as g a.e. picloram per mm girth) required to kill 80% of the trees were 0,012–0,016 for A. karroo; 0,016–0,037 for T. sericea and 0,037 for J. globiflora. Few of the treatments applied to B. spiciformis trees resulted in kill rates of more than 65%.     

多年生黑麦草组织培养与植株再生研究

对多年生黑麦草种子为外植体的植株再生过程进行系统研究,结果表明,在改良的MS培养基(MSM),以MS无机盐+9.9mg/L维生素B₁+9.5mg/L维生素B₆+4.5mg/L尼克酸+1mg/LCH+30g/L蔗糖+琼脂8g/L为基本成分,附加5mg/L2,4-D和0.05mg/LKT时,适合种子的愈伤组织诱导;继代培养基附加2mg/L2,4-D和0.1mg/LKT;分化培养基附加1mg/L2,4-D和1mg/LKT;生根培养基为无激素的MS培养基。完成植株再生约需12周,愈伤组织分化率为70%。     

野生黄花苜蓿组织培养及再生体系研究

以呼伦贝尔草原野生黄花苜蓿(Medicago falcata L.)无菌苗的子叶和下胚轴为外植体,对其组织培养及再生体系进行系统的研究,以期为其下一步转基因试验提供良好的受体。结果表明:最佳愈伤诱导培养基为MS+1.5 mg·L^-1 2,4-D+0.4 mg·L^-1 6-BA+3%蔗糖+0.7%琼脂,下胚轴和子叶的最佳愈伤诱导率均可达到100%。最佳胚性愈伤形成培养基为MS+0.5 mg·L^-1 KT+0.1 mg·L^-1 NAA+2%蔗糖+0.7%琼脂,胚性愈伤形成率为81.5%;最佳分化芽形成培养基为MS+0.25 mg·L^-1 KT+0.05 mg·L^-1 NAA+2%蔗糖+0.7%琼脂,分化芽形成率为36.5%。最佳生根培养基为1/2MS+0.5 mg·L^-1 NAA+1.5%蔗糖+0.7%琼脂,生根率为93.3%。愈伤诱导结果显示,供试黄花苜蓿材料个体间组织培养再生性存在较大差异,在同一激素水平上有大约1/3植株的愈伤状态优于其他植株。     

草地早熟禾新格莱德胚性愈伤组织原生质体培养及植株再生的研究

以草地早熟禾品种——新格莱德成熟种子为供试材料,在含3.0mg/L2,4-二氯苯氧乙酸(2,4-D)、0.5mg/L6-苄氨基嘌呤(6-BA)的MB₅培养基中进行胚性愈伤组织诱导的培养。并从生长了7～9个月的胚性愈伤组织中分离出原生质体,将该原生质体置于KM₈P培养基(含3.0mg/L2,4-D、0.5mg/L6-BA、100mg/L水解酪蛋白、100mg/L水解乳蛋白、1%蔗糖、0.4mol/L甘露醇)中进行了液体浅层培养。结果表明,新格莱德原生质体在上述KM₈P培养基中培养3d后出现第1次细胞分裂,2～3周后形成小细胞团,此时添加低渗培养液2～3次,小细胞团持续分裂并形成愈伤组织。当愈伤组织块长至3～5mm时,转入固体培养基MS+3.0mg/L2,4-D+0.5mg/L6-BA和MS+0.5mg/L萘乙酸(NAA)+5.0mg/L6-BA上进行培养,使其细胞增殖和分化,且逐步形成完整的植株。     

Activity of cefquinome against extended‐spectrum β‐lactamase‐producing Klebsiella pneumoniae in neutropenic mouse thigh model

Increasing prevalence of extended‐spectrum β‐lactamase (ESBL)‐producing Klebsiella pneumoniae (K. pneumoniae) is of clinical concern. The objective of our study was to examine the in vivo activity of cefquinome against ESBL‐producing K. pneumoniae strain using a neutropenic mouse thigh infection model. Cefquinome kinetics and protein binding in infected neutropenic mice were measured by liquid chromatography–tandem mass spectrometry (LC‐MS/MS). Dose‐fractionation studies over a 24‐h dose range of 2.5–320 mg/kg were administered every 3, 6, 12, or 24 h. The percentage of the dosing interval that the free‐drug serum levels exceed the MIC (%fT > MIC) was the PK–PD index that best correlated with cefquinome efficacy (R² = 86%). Using a sigmoid E_max model, the magnitudes of %fT > MIC producing net bacterial stasis, a 1‐log₁₀ kill and a 2‐log₁₀ kill over 24 h, were estimated to be 20.07%, 29.57%, and 55.12%, respectively. These studies suggest that optimal cefquinome PK/PD targets are not achieved in pigs, sheep, and cattle at current recommended doses (1?2 mg/kg). Further studies with higher doses in the target species are needed to ensure therapeutic concentration, if cefquinome is used for treatment of K. pneumoniae infection.     

苜蓿雄性不育系花药愈伤形成及分化培养条件的研究

以苜蓿雄性不育株系及其可育株系的花药为外植体,研究取材时间和不同激素配比对其愈伤组织诱导及分化的影响。结果表明,雄性不育株系花药培养时,以现蕾初期取材、MS为基本培养基的条件下出愈率较理想。愈伤组织诱导的适宜培养基为:MS+0.5mg/L 2,4-D+0.25mg/L 6-BA+0.2mg/L NAA+3mg/L KT+3%蔗糖+0.7%琼脂(出愈率66.7%);不育与可育植株花药愈伤适宜的分化培养基分别为:MS+1mg/L KT+0.2mg/L NAA+2%蔗糖+0.7%琼脂(分化率75%)和MS+4mg/L KT+0.2mg/L NAA+2%蔗糖+0.7%琼脂(分化率79%)。     

The influence of different forms and concentrations of nitrogen on total nonstructural carbohydrate allocation and growth in Digitaria eriantha

Abstract

Digitaria eriantha plants were grown under controlled conditions for a period of three months, during which time they were supplied with the following forms and concentrations of nitrogen: 50 mg/1 NO₃ ^?‐N, 200 mg/1 NO₃ ^?‐N, 200 mg/1 NH₄ ⁺‐N and a combined form containing both NO₃ ^?‐N and NH₄ ⁺‐N with a nitrogen concentration of 200 mg/1. Control plants received no nitrogen.

At monthly intervals both above and below ground components were assayed for soluble and insoluble carbohydrate contents. Dry mass and leaf areas were also measured.

The nitrogen treatments were found to influence the allocation of photosynthates into either soluble or insoluble carbohydrates. In above ground tissue, the soluble carbohydrate component decreased with time, while the insoluble component increased with time. In root tissue the reverse trends were observed. Both dry mass and leaf area development were enhanced in plants supplied with nitrogen in any form. It was suggested that growth of D. eriantha was influenced by carbohydrate fluctuations.     

Acepromazine‐dexmedetomidine‐ketamine for injectable anaesthesia in captive European brown hares (Lepus europaeus)

ObjectiveTo evaluate a combination of acepromazine, dexmedetomidine and ketamine (ADK) on induction and recovery from anaesthesia, and on physiological parameters in hares undergoing non‐invasive procedures.Study designProspective clinical study.AnimalsSixteen European hares (Lepus europaeus), seven males and nine females, aged (mean ± SD) 3.25 ± 0.9 months and weight 2.1 ± 0.6 kg.MethodsAcepromazine 1% (A), dexmedetomidine 0.05% (D) and ketamine 5% (K) were mixed and given intramuscularly (IM) at 0.25 mL kg^?1, representing 10 mg kg^?1 K, 0.25 mg kg^?1 A, 12.5 μg kg^?1 D. If the righting reflex was present after four minutes, a second injection of 0.15 mL kg^?1 (6 mg kg^?1 K, 0.15 mg kg^?1 A, 7.5 μg kg^?1 D) was administered IM. Surgical anaesthesia was judged as present when righting, palpebral, ear‐pinch and pedal withdrawal reflexes were absent. Anaesthetized hares were tagged, and underwent blood sampling and ocular ultrasound examination. Physiological parameters were recorded every ten minutes, and were compared by Kruskal‐Wallis tests.ResultsA single dose induced loss of righting reflex in 11/16 (69%) hares within four minutes; the second dose was effective in the remaining hares. Ten minutes after the loss of the righting reflex, a surgical plane of anaesthesia was present in all hares. Sleep time to regaining righting reflex was 34 ± 11 (range 21–62) minutes and recovery was calm. Although there were some statistical differences over time, cardiovascular parameters remained within an acceptable range but there was respiratory depression and hares were hypoxemic.Conclusions and clinical relevanceThe ADK mixture produced a smooth and rapid induction of anaesthesia, a low incidence of untoward side effects and full recovery after four hours. Supplementary oxygen might be advisable if a deeper plane of anaesthesia was required. Chemical restraint was adequate to perform non‐invasive procedures.     

紫花苜蓿基因转化的影响因素分析

通过农杆菌介导法对紫花苜蓿不同品种植株进行了抗旱基因转化的研究,得到了一套紫花苜蓿基因转化的优化体系。研究表明,100 mg/L的卡那霉素对苜蓿愈伤组织的生长有着显著的抑制效应。250 mg/L头孢霉素能够有效地抑制农杆菌菌株LBA4404的生长。紫花苜蓿供试材料被切后直接用OD600值为0.3~0.5的农杆菌LBA4404菌液侵染10~15 min;培养材料共培养3 d后在愈伤组织诱导培养基MS 2 mg/L 2,4-D 0.5 mg/LKT 30 g/L蔗糖 9 g/L琼脂 250 mg/L Cef上诱导出愈伤组织;在体细胞胚分化培养基MS 1.0 mg/L BA 0.3 mg/L NAA 30 g/L蔗糖 9 g/L琼脂 50 mg/L Kan 250 mg/L Cef上促进体细胞胚的分化;分化出的体细胞胚在再生培养基上(同分化培养基,Kan为80 mg/L)进一步发育成抗性转化苗;转化的无根小苗在生根培养基1/2 MS 1.0 mg/L IBA 1%蔗糖 0.8%琼脂 100 mg/L卡那霉素上可生长出根系。     

黄花苜蓿愈伤组织诱导及分化培养条件的研究

以黄花苜蓿子叶和下胚轴为外植体,研究不同激素配比对黄花苜蓿愈伤组织诱导及分化的影响,结果表明:MS+2,4-D 2mg/L+6-BA0.5mg/L+蔗糖3％+琼脂0.7％为适宜的愈伤组织诱导培养基;MS+ KT0.5mg/L+NAA0.1mg/L+蔗糖2％+琼脂o.7％为适宜的分化培养基;生根培养基为:1/2MS+ NAA 0.1mg/L+蔗糖2％+琼脂0.7％.下胚轴是诱导愈伤及分化的最佳外植体,诱导率可达100％,分化率可达80％.     

新疆野生黄花苜蓿愈伤诱导及分化的研究

以新疆野生黄花苜蓿(Medicago falcata L.)为材料,通过愈伤组织诱导及分化途径获得再生植株;从种子硬实、外植体、激素(2,4-D和KT)、培养基方面探讨野生黄花苜蓿组织培养的影响因素。结果表明:4℃低温处理与浓硫酸浸种结合是破除黄花苜蓿硬实的较优方法,发芽率达90%;下胚轴为诱导愈伤组织的最佳外植体;MS培养基比改良的SH培养基对愈伤组织的诱导更有效,MS诱导培养基为MS+2,4-D 0.5 mg·L^-1+KT 0.8 mg·L^-1+蔗糖30 g·L^-1+琼脂粉7 g·L^-1,出愈率达到80%;浅绿色和浅黄色的愈伤组织在MS+2,4-D 0.2 mg·L^-1+KT 0.4 mg·L^-1+CH 1 g·L^-1+蔗糖20 g·L^-1+琼脂粉7 g·L^-1的培养基上分化较好,分化率为30%。研究结果将为黄花苜蓿生物技术育种奠定一定的基础。     

蒙古冰草根尖高效组培再生体系的建立

以蒙古冰草根尖为外植体研究不同激素配比对蒙古冰草愈伤组织诱导及分化的影响,结果表明:蒙古冰草根尖最适愈伤诱导培养基为MS+2,4-D 1.0mg/L+6-BA 0.5mg/L+蔗糖20.0g/L+琼脂7.0g/L,诱导率为73.33%;最适分化培养基为MS+KT 3.0mg/L+NAA 1.0mg/L+蔗糖20.0g/L+琼脂7.0g/L,分化率为70.00%;最适生根培养基为1/2 MS+NAA 0.1mg/L+蔗糖20.0g/L+琼脂7.0g/L,生根率为86.68%。首次建立了以蒙古冰草根尖为外植体的再生体系,再生过程仅70~80d,为蒙古冰草高效遗传转化体系的构建提供了参考。     

马蹄金子叶的愈伤诱导与植株再生研究

以不同植物生长调节剂组合和不同基本培养基,探讨了马蹄金子叶离体培养的方法和影响因素。结果表明,不同植物生长调节剂组合的培养基对愈伤组织的诱导频率有显著影响,出愈率为16%～100%;以MS或B5培养基作诱导愈伤组织的基本培养基效果较好;将子叶接种到MS+1.0mg/L2,4-D+0.2mg/L6-BA的诱导培养基中诱导愈伤组织,再用MS+0.1mg/L2,4-D+2.0mg/L6-BA+3.0mg/LAgNO3作分化培养基出苗效果最佳,愈伤组织分化频率高达20.7%。     

The influence of nitrate and ammonium forms of nitrogen fertilizer on the growth and osmoregulation of digitaria eriantha and Chloris gayana grown under saline conditions

Abstract

Digltaria eriantha and Chloris gayana were grown under controlled conditions for three months and were treated with a nutrient solution containing 150 mMol NaCl and the following nitrogen sources: 25 or 200 mg/l NH₄ ⁺‐N or NO₃ ^?‐N or no nitrogen. The application of nitrogen was found to stimulate growth, i.e. leaf area and dry mass in both grasses, with a greatest growth response to both NH₄ ⁺—N treatments in D. eriantha, and NH₄ ⁺‐N and NO₃ ^?—N treatments in C. gayana. Proline accumulated in both grasses, but this accumulation followed different trends in the two grasses. Soluble sugars (non‐structural) accumulated in the above ground component in D. eriantha, while in C. gayana soluble sugars accumulated predominantly in the roots, possibly as osmotica, or for storage and may thus have been available for regrowth.     

扁蓿豆愈伤组织诱导和分化条件的研究

以扁蓿豆3个品系的下胚轴和子叶为外植体,研究不同培养基、不同激素种类和配比对愈伤组织诱导的影响,以及不同分化培养基对愈伤组织分化的影响.结果表明:下胚轴的愈伤组织诱导率普遍高于子叶;品系B1、B2最佳愈伤组织诱导培养基为MS+0.5mg/L 2,4-D+0.5mg/L 6-BA,品系B3最佳愈伤组织诱导培养基为MS+0.5mg/L 2,4-D+0.7mg/L 6-BA;适宜分化的培养基均为MS+1mg/L KT+1mg/L 6-BA.     

Enhancement of viability of a probiotic Lactobacillus strain for poultry during freeze‐drying and storage using the response surface methodology

A rotatable central composite design (CCD) was used to study the effect of cryoprotectants (skim milk, sucrose and lactose) on the survival rate of a probiotic Lactobacillus strain, L. reuteri C10, for poultry, during freeze‐drying and storage. Using response surface methodology, a quadratic polynomial equation was obtained for response value by multiple regression analyses: Y = 8.59546 ? 0.01038 X₁ ? 0.09382 X₂ ? 0.07771 X₃ ? 0.054861 X₁² ? 0.04603X₃² ? 0.10938 X₁X₂. Based on the model predicted, sucrose exerted the strongest effect on the survival rate. At various combinations of cryoprotectants, the viability loss of the cells after freeze‐drying was reduced from 1.65 log colony forming units (CFU)/mL to 0.26–0.66 log CFU/mL. The estimated optimum combination for enhancing the survival rate of L. reuteri C10 was 19.5% skim milk, 1% sucrose and 9% lactose. Verification experiments confirmed the validity of the predicted model. The storage life of freeze‐dried L. reuteri C10 was markedly improved when cryoprotectants were used. At optimum combination of the cryoprotectants, the survival rates of freeze‐dried L. reuteri C10 stored at 4°C and 30°C for 6 months were 96.4% and 73.8%, respectively. Total viability loss of cells which were not protected by cryoprotectants occurred after 12 and 8 weeks of storage at 4°C and 30°C, respectively.