云南小麦籽粒硬度分布研究*

 硬度是小麦重要的品质性状之一，主要影响磨粉品质和食品加工品质。研究用云南省各地州有代表性的大面积主推品种39份调查了云南省小麦品种的籽粒硬度分布，结果表明云南省小麦籽粒硬度变化范围大,表现为硬质麦、软质麦和混合类型小麦共存，其中中等偏硬的小麦品种最普遍，占53.8%；中等偏软的比例最低，为7.7%；极端类型软质麦的比例较高，为17.9%。此外，云南省自育小麦品种的籽粒硬度与国内外品种差距不大。     

加工型番茄果实硬度特异材料的果实特性及果肉组织特征

为能分析不同硬度加工番茄品系的果实特性和果肉组织特征差异,该文以田间发现的特异高硬度果实材料WT-75和WT-76为研究对象,分析了果实的可溶性固形物、总酸、番茄红素、单果耐压力、果肉组织含水量和可溶性果胶等主要品质指标差异,并利用石蜡切片和扫描电镜技术,研究不同材料间的果肉组织特征差异.结果表明,相较于对照ZH-10较软的手捏感官硬度评价,WT-75和WT-76的评价为特硬.利用平板挤压法测试硬度,WT-75和WT-76的耐压力分别为79.70和77.71 N,极显著高于(P＜0.01)对照ZH-10的耐压力.在测试的果实主要品质指标中,WT-75和WT-76的可溶性果胶含量显著高于(P＜0.05)对照ZH-10,其他的品质指标在各研究材料间不存在差异的显著性(P＞0.05).WT-75和WT-76的果肉组织石蜡切片结果表明,在200 μm视野下WT-75和WT-76的平均果肉细胞面积分别为0.037 6和0.053 2 mm2明显(P＜0.01)小于ZH-10(果肉细胞面积为0.089 9 mm2),且排列紧密.常温放置35d后,WT-75的果实腐烂率达93％,而对照ZH-10腐烂率为64％,WT-76的腐烂率为33％,ZH-10和WT-76的腐烂程度小于(P＜0.05)WT-75.结合与果肉组织的扫描电镜结果,相较对照ZH-10和WT-76,WT-75的果皮中分布了大量的小皮孔,这种果皮结构的特异性可能是导致果实的耐贮藏性显著降低的主要原因.通过对特异果实硬度加工型番茄果实主要品质、果肉组织特征和常温耐贮藏性研究,为后期适宜加工型番茄杂交品种亲本的选配筛选提供理论依据.     

Influence of type of raw material on fishmeal physicochemical properties,the extrusion process,starch gelatinization and physical quality of fish feed

The aim of this study was to investigate the impact of two types of fish raw material on fishmeal (FM) physicochemical properties, specific mechanical energy, starch gelatinization and physical feed quality. Eleven feed mixes based on six independent FMs from herring (FMH) and five from sand eel (FMSE) were extruded according to standardized conditions. Type of fish raw material influenced FM physicochemical properties and had significant impact on starch gelatinization and pellet hardness. Multivariate models were established based on partial least squares regression (R² = 0.637–0.999). Improved degree of starch gelatinization was associated with increased degree of protein hydrolysis (P = 0.011) and by replacement of FMH with FMSE in the feed mix (P = 0.012). A large span in pellet hardness was observed (4.9–94.1 N). Improved hardness was associated with decreased level of non‐soluble protein (P < 0.001) and by replacement of FMSE with FMH (P < 0.001). For FMSE, improved hardness was associated with decreased level of non‐soluble protein (P < 0.001) and increased degree of protein hydrolysis (P = 0.002), compressed bulk density (P = 0.039) and dust fraction (P = 0.001). The underlying physical and chemical mechanisms are discussed. The study documents differences in technical quality of FM produced from herring and sand eel with significant impact on fish feed extrusion and pellet quality.     

In vitro survival and the effect of water chemistry and oxidative chemical treatments on isolated gill amoebae from AGD-affected Atlantic salmon

Amoebic gill disease (AGD) of cultured salmonids in Tasmania is caused by the amphizoic parasitic amoeba Neoparamoeba pemaquidensis. The freshwater tolerance of amoebae isolated from the gills of AGD-affected salmon (predominantly N. pemaquidensis) was tested in vitro using a trypan blue exclusion assay. Amoebae exposed to water containing high concentrations of Ca²⁺ or Mg²⁺ (200 mg l⁻¹) showed high levels of survival up to 3 h of exposure. Exposure to water containing elevated Na⁺, choline chloride or water at different pH all had no significant survival of amoebae. Exposure of amoebae to different concentrations of chlorine dioxide, chloramine-T or hydrogen peroxide in artificially hard water demonstrated that chloramine-T and hydrogen peroxide were the most efficacious at killing amoebae in vitro. This work suggests that the hardness of freshwater may be an important factor for the survival of marine amoebae (predominantly N. pemaquidensis) on the gills of AGD-affected salmon and have significant implications with regard to the efficacy of freshwater bathing practices for the control of AGD on farms. Additionally, chloramine-T and hydrogen peroxide appear to be efficacious at killing marine gill amoebae in vitro and may be useful for the control of AGD in farmed Atlantic salmon.     

耐裂性不同的西瓜发育过程中果实力学特性及果皮结构动态研究

【目的】了解耐裂和易裂西瓜果实发育过程中的力学特性和果皮结构变化规律,揭示西瓜耐裂性与果皮结构及果实力学特性的关系,为耐裂西瓜品种选育提供理论依据。【方法】以耐裂种质 S1111 和易裂种质201609019 为试验材料,采用质构仪分析其不同发育时期的果实硬度、果实裂应力变化;利用石蜡切片法观测其果皮结构组织变化。【结果】在果实发育过程中,S1111 的果实硬度和裂应力分别是 201609019 的 1.35~1.54 倍和1.85~6.03 倍,差异显著。组织学研究表明,S1111 与 201609019 的果皮组织结构具有明显差异,S1111 的果皮细胞排列紧密并具有明显的石细胞团结构,其果皮和外果皮厚度均极显著高于 201609019;而 201609019 的表皮细胞更长、外果皮细胞和中果皮细胞更大,细胞面积显著大于 S1111,其外果皮细胞和中果皮面积分别是 S1111 的1.67~3.28 倍和 2.77~5.69 倍。相关性分析表明,西瓜果实硬度和果实裂应力与果皮厚度、外果皮厚度呈显著正相关,与表皮细胞长度、外果皮细胞面积及中果皮细胞面积呈显著负相关。【结论】果实裂应力和果实硬度大小可用于评价西瓜果实耐裂性,且在果实发育后期评价更合适。     

不同梅花品种在北移驯化中形态性状的变异

首先对北京市20多个梅花品种的性状进行了观测、编码;随后选取在武汉、南京也有性状记载的19个品种,对不同品种在北移驯化过程中形态性状的变异进行了比较、分析。结果表明:33个性状中,差异显著的有17个,其中营养器官性状8个,表现为自然树冠变开张,主干颜色变浅、驳纹增多、皮孔密而小,枝刺多,小枝细、趋向横生;生殖器官性状7个,表现为花蕾形状变紧实、花态趋向收拢,花梗短,花瓣、雄蕊变瓣减少,雄蕊着生状态趋向四射、花香变淡;生态性状2个,表现为着花状况变稀疏、群体花期变短。小枝颜色、每节着花数、瓣萼、萼瓣、花瓣颜色、雄蕊相对长度等性状相对稳定(差异不显著)。19个品种中,差异显著的为‘白须朱砂’、‘素白台阁’、‘小红朱砂’、‘乌羽玉’、‘三轮玉蝶’、‘粉玉宫粉’、‘小绿萼’、‘小宫粉’,表现了较强的可塑性和适应能力,具有相对大的抗寒潜力。     

基于小波变换的小麦硬度声学测定方法研究

信息技术近几十年以来发展迅速,而声学的发展已经有几百年的历史,信息科学与传统的声学相结合产生的信息声学技术成为当代科研领域中的一个热点。小麦颗粒碰撞物体时产生的音频信号含有大量的信息。为此,通过小波变换对小麦音频信号进行处理,提取一些有用的特征参数,利用线性回归分析方法,建立提取的特征参数与小麦硬度之间的回归模型。结果表明,所建模型的线性相关系数r2达到了0.950 5。     

PLA沙障对土壤硬度的影响

 为了解新材料聚酯纤维(PLA)沙障对沙丘土壤硬度的影响,通过测定铺设PLA沙障沙丘表层的土壤硬度,并以铺设麦草沙障沙丘及裸沙丘为对照,对比研究各种规格、迎风坡、坡顶及背风坡土壤硬度的差异。结果表明:铺设PLA沙障沙丘表层土壤硬度显著高于麦草沙障沙丘(P<0.001),且2者土壤硬度均显著高于未铺设沙障的裸沙丘(P<0.001);2 m×2 m和1 m×1 m PLA沙障土壤硬度比较接近,均显著小于3 m×3m规格的(P<0.01),而麦草沙障3种规格的土壤硬度差异较小;2种沙障所在沙丘不同部位土壤硬度变化趋势相似,均是迎风坡的最大,坡顶次之,背风坡的最小;PLA沙障及麦草沙障单个障格内的土壤硬度分布都是不均匀的,并且二者的土壤硬度分布规律存在差异。     

水硬度对七彩神仙鱼幼鱼发育的影响

采用不同硬度的水对七彩神仙鱼幼鱼进行饲养。6周龄幼鱼在硬度为7.94°dH±0.30°dH时饲养84d后,比在硬度为14.71°dH±0.23°dH水中的幼鱼个体大,生长速度快。表明较高硬度的水有利于七彩神仙鱼幼鱼的生长发育。     

膜片对管上式压力补偿灌水器水力性能的影响

膜片的可变性是压力补偿灌水器实现高压条件下稳定出流的主要因素,膜片的特征参数及与灌水器壳体的相互配合直接影响灌水器的整体性能.以PLASTRO 公司生产的Supertif-03120-0003型管上式压力补偿灌水器为原型件,借助(3DP)快速成型技术制作管上式灌水器试验件,选取硅橡胶材质的弹性膜片,对膜片的厚度、硬度进行单因素分析和正交试验,研究弹性膜片不同特征参数对灌水器水力性能的影响.经过多重比较分析得出,灌水器水力性能与弹性膜片特征参数之间的定性关系,为压力补偿灌水器的优质膜片材料的研发提供依据.本试验结果表明:低流态指数最优组合为A₃B₄,即弹性膜片的厚度为2.0 mm,邵氏硬度为60.