采收期对‘黄冠’梨果实品质影响的研究

研究采收期对‘黄冠’梨果实品质的影响,旨在揭示‘黄冠’梨果实发育后期果实品质因子的变化规律,为生产中确定‘黄冠’梨的最佳采收期提供理论依据。以‘黄冠’梨为试材,通过测定不同采收期时的单果重、可溶性固形物含量、Vc含量、硬度,并利用液相色谱法测定不同采收期果实的糖酸组成和含量,分析‘黄冠’梨果实发育后期果实品质因子与采收期的关系。结果表明,自果实发育106天开始,随采收期的延后,果实硬度呈显著下降,果实可溶性固形物含量呈上升趋势,并于果实发育137天时达到高峰;Vc含量变化较小,仅在120天时显著较高;在近成熟期采收的果实中糖以果糖为主,占70.09%~84.00%,以果实发育137天时最高;果实中酸以苹果酸为主,苹果酸占酸总量的93.05%~97.28%,苹果酸D占苹果酸的82.92%~91.84%。随采收期的延后,果实发育天数延长,果酸含量下降,采收越晚糖酸比越高。‘黄冠’梨果实发育130~137天时,果实的可溶性固形物、果糖、葡萄糖、蔗糖和Vc含量都较高,糖酸比和果肉硬度适宜,以获得‘黄冠’梨最佳品质为目标的适宜的采收期为8月8—15日。     

Serological status of cattle to bovine viral diarrhoea virus and bovine herpesvirus 1 at entry to and exit from Australian feedlot backgrounding facilities

A total of 6195 cattle were enrolled in this observational study. Serum antibody concentrations to bovine herpesvirus 1 (BHV1) and bovine viral diarrhoea virus (BVDV) were measured at entry to and exit from backgrounding facilities to assess their statuses on arrival and the extent of seroconversion to these viruses during backgrounding. The backgrounding facilities were contiguous with five feedlots in: Queensland (two sites), New South Wales, South Australia and Western Australia. Cattle were held in the backgrounding facilities for a minimum of 29 days and a median of 34 days. On backgrounding facility entry, 32.7% of the study population was seronegative to BVDV, but 85.7% was seronegative to BHV1. After commingling in the backgrounding facilities, of the cattle that were seronegative on backgrounding facility entry, 33.9% and 30.3% showed a serological increase to BVDV and BHV1, respectively. At backgrounding facility exit, when cattle were placed in their feedlots, 19.6% and 59.1% were seronegative to BVDV and BHV1, respectively, and 0.26% were persistently infected with BVDV. There was a strong association between seroincrease to BVDV and seroincrease to BHV1 (P = 0.005) at animal level in cohorts known to contain an animal persistently infected with BVDV.     

海砂和电石渣对吹填土理化性状的影响及水盐动态研究

以吹填土、海砂、电石渣为材料,采用土柱模拟实验研究吹填土:海砂:电石渣=0.55:0.40:0.05比例的混合基质淋洗脱盐下的水盐动态,脱盐后基质的理化性质,以确定是否适合做园林绿化土壤。结果表明:基质的水盐运移可分为盐峰的形成、下移和消失3个阶段;脱盐深度与各层淋洗水量呈直线相关关系(y=0.0028x-3.2675(R2=0.9124))提供了淋洗定额的参考价值;脱盐后0-60cm和60-140cm深度的土层,盐分离子组成分别为Ca2+-HCO3-、SO42-型和Ca2+-SO42-型;通体质地为细砂土,通气透水性强;也没有脱盐碱化的现象;基质肥力水平较低。可见3种材料采用该比例做园林绿化基质是可行的,但是脱盐后培肥等配套措施至关重要。     

Species identification of non-tuberculous mycobacteria from humans and cattle of Chad

In Chad, during a study on tuberculosis in humans and cattle, 52 non-tuberculous mycobacteria (NTM) strains were isolated. By means of INNO-LiPA, PRA-hsp65 amplification and sequencing of 16S rDNA, NTM species of 25/52 isolates were identified. M. fortuitum complex (8) was the most frequent species, followed by M. nonchromogenicum (4) and M. avium complex (4). PRA method could identify M. fortuitum 3rd variant among isolates derived from cattle specimens. This finding could confirm the existence of farcy in the Chadian cattle population as M. fortuitum 3rd variant and putitative pathogen M. farcinogenes can't be distinguished by the methods used in this study. Half of the NTM isolates could not be specified and we considered them as contaminants from the environment.     

赣棉11号高效节本生产技术集成与示范

通过赣棉11号原种生产与加工技术和高效节本生产技术进行有机集成与示范,提供一整套成熟的“赣棉11号”原种生产技术操作规程、种子加工技术规程和优质高效节本生产技术操作规程,加速了农业科技成果的转化应用,提高了江西省棉花生产的水平,江西省的原棉品质得到了改善,取得了良好的社会、经济和生态效益.     

Evaluation of measurement accuracy and comparison of two new and three traditional net radiometers

Net radiation (R_n) is the sum of the radiant energy at the Earth's surface and is a major component of the surface energy balance. However, R_n is difficult to measure accurately, and multiple instruments are available to measure it. Two new instruments (Hukseflux Thermal Sensors B.V., model NR01; Kipp & Zonen B.V., model CNR 2) have been released within the past two years. We compared these models, two less-expensive older models (Kipp & Zonen B.V., model NR-Lite; Radiation and Energy Balance Systems, Inc., model Q*7.1), and a more expensive older model (Kipp & Zonen B.V., model CNR 1) over a uniform turfgrass surface for 33 days in mid-summer. Three replicates of each radiometer were included in the study (except for the CNR 1). The instruments that independently measure the four components of R_n (models CNR 1 and NR01) were typically the most accurate. Incoming shortwave measurements from the four component instruments were compared to a reference pyranometer, and outgoing longwave measurements were compared to infrared measurements of surface temperature. The differences from the reference pyranometer and surface temperature measurements were typically 2% or less. There was a difference of approximately 5% in incoming longwave measurements between these two radiometer models. This is likely due to differences in calibration approaches, which are discussed. This emphasizes the need for standardization of longwave calibration methods and establishment of a world reference for longwave radiation. The instruments that do not separate shortwave and longwave radiation into component measurements (net all-wave radiometers, models NR-Lite and Q*7.1) were generally the least accurate, and had offsetting day and night differences that reduced daily total R_n differences relative to the reference. The CNR 2 measures net shortwave and net longwave, and is an intermediate between a four component instrument and a net all-wave instrument. The R_n measurement accuracy of the CNR 2 typically fell between that of the two groups. Differences among radiometers tended to be larger at night than during the day, indicating higher variability in longwave measurements. An inversion (flip) test in the field showed the NR-Lites and Q*7.1s had well matched detectors, however two of the three replicate CNR 2s had mismatch errors greater than 5%. This becomes important for measurements over non-vegetated surfaces. The data presented here should be helpful in selecting the most cost effective instrument for a given application.     

商品混凝土运行模式存在的问题及解决对策

分析了现行商品混凝土运行模式,认为现行模式在过去的一定时期是合理的,随着混凝土技术的发展,混凝土性能的影响因素更加复杂,混凝土质量事故增加,作为生产关系的商品混凝土运行模式开始阻碍混凝土技术的发展.为此提出了商品混凝土生产施工一体化的运行模式,解决了现有模式职责不清的问题,混凝土的质量事故由商品混凝土搅拌站承担.这一模式有利于混凝土性能的提高.     

草坪型高羊茅的研究进展与展望

高羊茅Festuca elata由于其较强抗性与较广的适应性,已在我国广泛应用于各类草坪建植.从适应性、种子生产情况、养护管理技术及抗性生理机制四方面阐述了国内外的研究进展,并指出存在的问题及其发展趋势,以期为高羊茅的进一步研究与利用提供参考.     

辅酶Q_(10)菌种选育及高通量筛选研究进展

辅酶Q10在预防和治疗人体疾病上起到非常重要的作用,广泛应用于化妆品和保健品领域,其市场需求和工业产量均持续扩大。微生物发酵法制备辅酶Q10是目前最经济且有前景的方法,而选育获得高产菌株是微生物发酵生产的关键。通常,采用传统或现代遗传改造技术处理菌株,产生大量突变后代,然后从中筛选出增幅最大的高产菌株。由于微生物突变是随机不定向的,因此高通量的筛选技术是实现突变库快速高效筛选和提高育种效率的保障。综述了近年来国内外在辅酶Q10高产菌株选育方面的技术和原理进展,以及显色定量法、紫外薄层色谱、HPLC,UPLC等技术在其高通量筛选方面的应用等相关研究进展。     

玉米新品种渝单35特性及高产栽培制种技术

渝单35(区试代号渝301)于2011年通过重庆市农作物品种审定委员会审定。该品种通过多年试验鉴定,表现为品质优、大穗,产量较高、增产潜力大,适应性好。渝单35适宜在重庆市中低山区、丘陵、平坝及类似生态区作春玉米种植。