玉米收储制度改革背景下吉林省农户生产经营困境及对策研究

吉林省执行国家玉米临时收储政策以来,玉米收储价格持续走高,种植面积和产量不断扩大,有效保障国家粮食安全和广大农民利益。但临储制度所带来的库存、销售等方面的问题也逐渐显现。2016年,国家发改委联合中央农办、财政部等部门,正式启动"市场化收购"加"补贴"模式,取消玉米临时收储政策。收储制度改革作为我国农业供给侧改革的重要组成部分,在建立更加完善的市场秩序过程中,客观上引发了产业链各环节的不适应甚至生产经营困境。本文利用2016～2017年吉林省72个玉米种植样本村的调查数据,分析玉米收储制度改革对吉林省不同规模玉米种植农户生产经营造成的影响,并针对消极影响所带来的种植规模扩大、种植结构调整等困境,提出相应的对策和建议。     

保存过程对土壤生化指标的影响及保存土样的应用

土壤样品的生化指标反映了样品采集时期的生态与环境信息,具有极为重要的科学研究价值。样品的生化指标在保存过程中是否发生变化,是保存样品应用中应关注的重点问题。本文总结了各类土壤生化指标在不同保存条件、保存时间下的变化,表明长期保存的土壤样品适用于全量元素含量测定、土壤微生物群落结构分析、DNA/RNA序列分析、土壤污染物分析和土壤酶活性的比较研究,而土壤速效成分以及呼吸、硝化等代谢过程相关指标则不宜采用保存土样。土样长期保存应采用风干、磨口玻璃瓶密封、常温保存的方式。保存土样应用过程中应注意避免取样、分析时的环境污染,采用合适的分析测试技术,并考虑不同类型土壤保存效应的差异。随着分析技术的发展,保存土样中更多的历史环境信息将得以发掘,发挥出更大的科研价值。     

Effect of short heat shocks applied during grain development on wheat (Triticum aestivum L.) grain proteome

In the field, developing cereal grains are often exposed to short periods of very high temperature (>35 °C) that may dramatically affect grain yield and flour quality. Here we report on the effect of 4 h of heat shock (HS) at 38 °C applied on four consecutive days during the linear phase of storage compound accumulation on grain proteome of the winter bread wheat. At maturity the average single grain dry mass and the total quantity of nitrogen per grain were 25% and 16%, respectively lower for the HS treatment than for the control, resulting in a higher (+1.6% dm) grain protein concentration in HS grains. Individual albumin–globulin, gliadin and glutenin protein fractions from grains collected just before the HS and 1, 8, and 26 (ripeness maturity) days after the HS were quantified then analysed by 2-dimensional electrophoresis followed by MALDI-TOF and MS/MS identification. The quantity per grain of 10 gliadins and 3 low molecular weight glutenin subunit proteins were significantly affected by HS. Thirty-eight HS responsive albumin and globulin proteins were identified, including several enzymes involved in carbohydrate, redox, and lipid metabolisms. One protein was transitorily induced in response to HS. Detailed discussion of the expression of these proteins is presented.     

包装袋对核桃青果贮藏效果对比试验

为了探明不同包装袋对青皮核桃在冷藏期间贮藏效果的影响,采用气调保鲜袋PE40、PE50硅窗袋g50、g55、g60、g656种包装袋。以清香青果为试材研究了不同贮藏期中贮藏效果对比试验。结果表明:与普通硅窗袋相比核桃青果贮藏宜采用自发气调袋,在PE40~PE50,建议选择P40袋。     

Germination pretreatment and storage behavior of Terminalia laxiflora seed

Terminalia laxiflora Engl.&Diels.is an important indigenous and multi-purpose species in Ethiopia.However threatened due to low germination and its storage behavior is unknown.In this study,we aimed to(1)test pretreatments for breaking the dormancy of T.laxiflora seed and(2)determine its storage behavior.Seeds were subjected to four pretreatments such as soaking,scarification,high-temperature,and control.Experiments were done before storage and after 2 years of dry storage at cold temperature(-10℃)based on randomized design with four replicates.The first round of experimental results showed that T.laxiflora seeds with high temperature treatments at 78℃for 10 min showed significantly higher germination percentage(80%).In the second round experiment,high-temperature treatment at 78℃for15 min,cold water soaking,high-temperature treatment at78℃for 10 min,hot water soaking,and high-temperature treatment at 78℃for 5 min showed significantly higher germination percentage from the remaining treatments(75,64,58,56,and 53%,respectively).To break the dormancy of T.laxiflora seed and attain good germination result,seeds should be pretreated with high-temperature at 78℃for 10 min to test the initial germination before storage and should be pretreated with high-temperature(at 78℃for15,10,or 5 min),soaked in cold,or hot water for 24 h to monitor the germination after storage.The two experiments show that T.laxiflora produces orthodox seed.     

富硒大果山楂果实中有关酶活性及贮藏品质的研究

[目的]探索硒在大果山楂贮藏保鲜中的应用,并为开发富硒大果山楂提供理论依据。[方法]以富硒大果山楂为原料,对其果实中有关酶活性及贮藏品质进行研究。[结果]富硒大果山楂果实中过氧化物酶(POD)和多酚氧化酶(PPO)的活性比对照组分别降低了49.2%和37.5%,超氧化物歧化酶(SOD)和过氧化氢酶(CAT)的活性比对照组分别增加了16.7%和33.5%。大果山楂果实硬度为25.29 N/cm~2,维生素C的含量为1 186.50 mg/kg,可溶性总糖的含量为144.00 g/kg,可溶性固形物的含量为16.60%,较对照组分别增加了13.2%、9.5%、29.0%、3.7%。[结论]硒能延缓大果山楂果实的成熟衰老,改善其品质。     

咪鲜胺对柑橘不同品种的保鲜效果评价

柑橘果实在贮藏期间极易发生青霉病、绿霉病、炭疽病等多种病害。为了减轻病害造成的损失,笔者在自然通风贮藏库内用咪鲜胺分别对锦橙、血橙、温州蜜柑和夏橙等4个柑橘品种进行了防腐保鲜效果研究。结果表明咪鲜胺333.33mg/㎏对青霉病、绿霉病、炭疽病和总病害均有较好的保鲜效果,只不同品种保鲜时间各异。以对锦橙和血橙的保鲜时间最长,贮藏期可达120天;其次是温州蜜柑,贮藏期可达60天;对夏橙的保鲜时间最短,只30天。对青霉病、绿霉病的效果,锦橙和血橙达120天,温州蜜柑达90天,夏橙达60天;对炭疽病的效果,锦橙可达120天,血橙达90天,温州蜜柑可达60天,夏橙只30天。咪鲜胺浸药处理对4个品种柑橘的失重率没有影响,只随着贮藏时间的延长,失重率均逐渐增加。咪鲜胺处理对果蒂保持绿色有一定效果,对不同品种柑橘果实内在品质、外观色泽和口感没有负面影响。     

Stable recombinant alpaca antibodies for detection of Tulip virus X

For detection of the plant pathogenic Tulip virus X (TuVX), a panel of six recombinant antibodies was identified. To this end, a repertoire of variable domains from heavy-chain immunoglobulins (VHH) was cloned from an alpaca, which had been immunized with TuVX. Binding domains were selected by phage display and panning on immobilized TuVX particles. Recombinant VHH antibodies were tested for sensitivity in a sandwich ELISA, and were demonstrated to be readily able to distinguish TuVX-infected tulip leaf material from uninfected leafs. No cross-reactivity of the VHH antibodies to related flexiviridae was observed. Recombinant VHHs maintained their reactivity upon storage at −20°C for over a year. The effect of incubation at higher temperatures for prolonged time was studied. Two out of three VHH proteins retained activity after several weeks of storage at 37°C.     

莲子热加工及其贮藏过程中硬度变化规律的研究

为进一步开发莲子深加工产品,对比研究干莲和鲜莲在不同热加工处理及其贮藏过程中硬度的变化.结果表明:热加工过程中莲子的硬度逐渐降低,降幅随着热加工温度的升高而增大;鲜莲最长热加工时间为12 min,干莲则为25 min,同时为保证莲子的充分熟化,热加工温度需达到90℃以上;在贮藏过程中,熟化莲子的硬度在7d内迅速增大,而后处于较平稳状态,干莲硬度均大于鲜莲,为鲜莲的1.4～1.6倍;冷热激变处理可使鲜莲在贮藏过程中硬度的增幅降低(由99.11％降低55.58％),并保持较好的表观结构,在某种程度上有利于莲子产品的深加工.     

Temperature‐dependent feed requirements in farmed blue mussels (Mytilus edulis L.) estimated from soft tissue growth and oxygen consumption and ammonia‐N excretion

Feed requirements were estimated from specific growth rates in standardized soft tissue dry weight (SGR_DW’) and atomic O:N ratios for mussels fed seven rations of microalgae (5–735 μg C h^?1 ind^?1) at 7 and 14°C respectively. The mean oxygen consumption and ammonia‐N excretion rates were significantly higher at 14°C (0.29 μg O² and 27.3 μg N ind^?1 h¹) compared with those at 7°C (0.16 μg O² and 11.4 μg N ind^?1 h^?1) (P < 0.05), resulting in O:N ratios between 3 and 45 at 7°C and 7 and 28 at 14°C. Low O:N ratios indicate protein catabolism and an unfavourable condition, whereas high ratios indicate that carbohydrate is the primary energy source. The measured SGR_DW’ suggests minimum feed requirements of ~240 and ~570 μg C ind^?1 h^?1 for weight maintenance at 7 and 14°C, with corresponding O:N ratios of 24 and 16, respectively, indicating a more stressed condition at 14°C. A 0.5% SGR_DW’ day^?1 was obtained by ~565 (O:N = 29) and ~680 (O:N = 23) μg C ind^?1 h^?1 at 7 and 14°C respectively. A positive and significantly higher SGR_DW’, with the lowest feed ration at 7°C compared with a negative SGR_DW’ at 14°C (P < 0.05), indicated that storage time can also possibly be prolonged at low temperatures if the mussels are not fed.