基于ISTA测试研究电商包装对莲雾货架品质的影响

莲雾果实皮薄肉脆,采后流通中极易产生机械损伤,严重影响果实货架品质。为了维持莲雾在物流运输中的货架品质,减少机械损伤,该研究基于ISTA 6-AMAZON.COM-SIOC TYPE A(ISTA 6A)测试标准模拟4种常用电商包装方式下（P1：瓦楞纸箱+单层网套、P2：瓦楞纸箱+双层网套、P3：瓦楞纸箱+发泡聚乙烯（expanded polyethylene,EPE）内衬和P4：泡沫箱+双层网套）莲雾果实的运输情况,并分析模拟测试后莲雾货架期（15℃,8 d）品质变化规律。结果表明,当外包装相同,缓冲形式不同时,双层网套（P2）组莲雾果实呼吸强度变化最为平缓,果皮亮度值为最低值32.86,果肉褐变指数（browning index,BI）与单层网套和EPE内衬相比上升了62.35%,其上升速率最慢,丙二醛含量（malondialdehyde,MDA）、过氧化物酶（peroxidase,POD）活性和多酚氧化酶（polyphenol oxidase,PPO）活性始终处于较低水平,货架品质显著好于单层网套（P1）和EPE内衬（P3）(P<0.05),原因在于单层网套的缓冲保护作用较...     

Finite dose diffusion studies: II. Effect of concentration and pH on NAA penetration through isolated tomato fruit cuticles

The effects of NAA [2‐(1‐naphthyl)acetic acid] concentration and pH on penetration of NAA from aqueous droplets (5 µl) through isolated tomato (Lycopersicon esculentum) fruit cuticles were studied using a finite dose diffusion system. Penetration time‐courses were characterized by a lag phase, which generally extended beyond the time of droplet drying. Initially penetration rates increased, reached a maximum penetration rate, remained constant for several hours, and then decreased with time. Penetration approached a plateau within 120 h after droplet application. Increasing NAA concentration in the donor droplet increased NAA penetration in both the presence and absence of the citric acid buffer (20 mM , pH 3.2). Maximum rates of penetration and the total amount of NAA that penetrated at 120 h were both linearly related to the initial concentration of the donor droplet (ranging from 0.001 to 0.1 mM NAA). The apparent first‐order rate constants for the concentration dependence of NAA penetration rates were greater with buffer than without (0.94 × 10⁻⁸ vs 0.50 × 10⁻⁸ m s⁻¹, respectively). While pH of the receiver solution (pH 6.2 vs 2.2) did not affect penetration, decreasing donor pH from 6.2 to 2.2 increased NAA penetration at 120 h. © 2000 Society of Chemical Industry     

Deposit structure and efficacy of pesticide application. 1: Interactions between deposit size,toxicant concentration and deposit number

Application of pesticides through a hydraulic nozzle produces deposits on a plant surface which have a spatial structure with elements of deposit size, number per area, and toxin per deposit. To investigate the relative contributions of these elements to the interaction of deposit structure and toxicant efficacy, we used a stochastic cellular automaton model of diamondback moth feeding on Bacillus thuringiensis (Bt)-treated cabbage – the Pesticide Dose Simulator (PDS) model. Data were analyzed using a specialized response surface approach called a mixture design. The advantage of this design was that it integrated the effects of deposit size, number per area and toxin per deposit on toxicant efficacy. Results from PDS simulations led to the following conclusions: (1) Deposit structure plays a major role in toxin efficacy. (2) Small deposits are not always the most efficacious. (3) Uniform coverage is not the best deposit structure if one is forced to limit application rates and field persistence. (4) Since uniform deposit structures allow an insect to live longer, uniform deposit structures should result in more insects acquiring sub-lethal doses. This may result in an interaction between ‘uniform coverage’ and the development of pesticide resistance in insect populations. (5) Percentage mortality and the level of crop protection are not necessarily correlated. Overall, these results help reconcile laboratory observations that small droplets are more efficacious with field observations that application of small droplets (eg from spinning disk sprayers) does not necessarily increase field efficacy. © 1999 Society of Chemical Industry     

存款保险制度的研究

我国存款保险制度已于2015年5月1日正式出台,它的存在对我国这样一个经济转轨的经济体而言是否有利大于弊的功效,这需要结合中国特色社会主义的特殊国情,借鉴国际经验和实例,对我国建立存款保险制度的利弊作出分析。     

Factors influencing the association between active ingredient and adjuvant in the leaf deposit of adjuvant-containing suspoemulsion formulations

BACKGROUND: For an oil adjuvant to enhance uptake of a particulate active ingredient (AI), it is hypothesised that closer association between the two should result in higher uptake. Accordingly, factors important for the spray deposit size on grapevine leaves have been investigated for a series of model suspoemulsion formulations containing colloidal crystalline AI or fluorescent pigment particles and an emulsion of an oil adjuvant with different degrees of wetting and different spray volumes. RESULTS: Low spray volumes (<100 L ha(-1)) produced small deposits with high particle-adjuvant association. Complementary uptake studies showed increased uptake with decreasing deposit size, in agreement with the above hypothesis. Higher spray volumes produced larger deposits that consisted of annuli formed by pinning of the contact line by particles. Low surfactant concentrations favoured particles in the annulus and adjuvant separated in the centre. Intermediate surfactant concentrations produced annuli containing both particles and adjuvant, while with high surfactant concentrations the deposits were large with few annuli.CONCLUSIONS: Small deposits result in high AI-adjuvant association. With larger deposits, annulus structures allow for enhanced AI-adjuvant association (5-20 times greater). The formation of annuli appears to be important in enhancing the biodelivery of particulate AIs in adjuvant-containing suspoemulsion formulations at intermediate spray volumes.     

不同栽培密度对小冬瓜新品种"黛宝"生长及产量的影响

[目的]研究不同栽培密度对小冬瓜新品种"黛宝"生长、开花和产量的影响。[方法]在小冬瓜果实膨大期,采样测量植株生长指标;在果实成熟期,采样测定植株果实性状和产量。[结果]40~80 cm株距对小冬瓜开花节位无显著影响;40 cm株距时,小冬瓜生长势明显弱于其余处理植株;尽管80 cm株距时植株单瓜重和果实纵径显著高于其他处理,但是,结合定植株数,栽培密度为60 cm时折合产量最高。40~50 cm株距时,植株化瓜现象严重,成瓜数少,产量低。[结论]畦宽1.5 m(含沟30 cm),双行种植,搭人字架栽培的条件下,小冬瓜秋季露地栽培的适宜株距为60 cm。     

水蜡树果中原花青素的最佳提取工艺研究

在单因素实验的基础上,采用正交L9(34)设计,研究提取温度、提取时间、提取剂、料液比对水蜡树果原花青素提取率的影响。结果表明:温度60℃,料液比1∶10,时间40 min,乙醇浓度60%提取时,原花青素的含量最高,可达2.413%;对原花青素提取率的影响作用大小顺序为提取剂提取时间提取温度料液比。     

番茄叶片蜡质和角质层与芝麻斑病菌侵染的关系

对4个抗芝麻斑病和6个感病番茄品种的叶片表皮抗性机制进行了研究。结果表明,采用氯仿去除叶片蜡质,用KOH或角质酶去除叶片角质层后,叶片芝麻斑病发病率显著增加;叶片蜡质和角质层同时去除的与叶片破损的芝麻斑病发病率差异不显著,表明叶片的抗性成分主要是蜡质和角质层。叶片蜡质含量测定结果表明,蜡质含量和角质层的厚度与品种的抗性有关。抗病品种叶片蜡质含量显著高于感病品种。叶片蜡质提取物在体外抑菌效果不显著,说明蜡质的抗性作用主要是物理性阻止芝麻斑病菌的穿透。     

水稻蜡质合成相关基因 OsCER4 自身启动子驱动的反义RNA转化植株获得

水稻OsCER4基因编码脂肪醛脱羧酶,与拟南芥CER1基因高度同源,是否参与植物表面蜡质合成尚不清楚,为了探讨其功能,扩增了OsCER4基因起始密码子ATG上游约2 kb的序列作为该基因的启动子,以常规技术将启动子和OsCER4基因反义片段克隆到pCAMBIA双元载体1380中,采用农杆菌介导法转化粳稻品种中花11,并进行了转化苗OsCER4蛋白的表达量变化分析.结果表明,成功构建了由OsCER4自身启动子驱动的反义RNA载体,并通过农杆菌介导法成功转入水稻中花11中,多数OsCER4基因反义转化植株为阳性转化植株,后代分离比符合3∶1,反义RNA转化植株在蛋白水平上的表达量下降.     

汉江上游郧县辽瓦店全新世古洪水研究

以汉江上游谷地郧县辽瓦店全新世古洪水滞流沉积剖面为研究对象,对其进行了洪水沉积学和水文学研究,并对其粒度组成、磁化率、烧矢量等理化性质进行了测量。结果证明,辽瓦店(LWD)剖面中夹有典型的古洪水滞流沉积物(SWD),它记录了一次特大洪水事件。利用地层学方法确定该次洪水事件发生在AD100-300之间(东汉-魏晋时代之间)。根据沉积学和水文学原理恢复了古洪水的洪峰水位在159.80m,以此计算出洪峰流量为65 420m3/s。根据2011年9月19日汉江洪水洪峰水位痕迹高程并利用相同方法反推洪水流量,所获流量数据与实测数据误差小于1%。