Chemical characteristics of straw fiber and properties of straw fiberboard with different pretreatments

Surface chemical characteristics of straw fiber have a great effect on the properties of interfacial conglutination between straw fiber and adhesives. In our study, straw was treated by four different methods—hot water, acetic acid, sodium sulfite and sodium hydrid sulfite. Our results show that the main chemical group of straw fiber, under the four different treatments, has not changed significantly. The acetic acid treatment reduces pH values of straw fibers and has a significant effect on the internal bonding strength of straw fiberboards. The modulus of rupture and modulus of elasticity did not clearly improve with the four different treatments. The thickness swelling of straw fiberboard treated in different ways is higher than that of standard values. It is concluded that acid treatment is optimal for producing good quality straw fiberboard. __________ Translated from China Forest Products Industry, 2006, 33(4): 24–26 [译自: 林产工业]     

Anatomical Study an the Development of Strawberry Fruit

The development of strawberry fruit,two cultivars-Gelila and Xiaoshi,was systematically studied by anatomical and embryological methods.The growth dynamics of fruit showed that the two cultivars performed similar changes with their fresh weight volume and structure,it included the first slow growth stage,the rapid growth stage and the second solw growth stage.The fruit was a typical polyachene with a ovule which belonged to a Poligonum type,the growth process of pollen tube from stigma to embryo sac was clearly observed by flourescence microscopy.Embryo development was similar to that of most dicotyle,and the mature embryo was orthotropous;Endosperm development was a nuclear type,and gradually disappeared with development:Seed coat consisted of 3-4 layer cells,and pericarp was composed of 6-8 layer cells which differentiated from ovary wall cell;The structure of receptacle was a typical stem which consisted of epidermis,cortex and vascular cylinder.With development,the cortex and pith of fruit contained plentiful parenchyma tissue,and they were mainly edible sections.     

Molecular adaptations of glucose and lipid metabolism to different levels of dietary carbohydrates in juvenile Japanese flounder Paralichthys olivaceus

Japanese flounder juveniles (initial body weight: 7.12 ± 0.02 g) were fed three diets containing 0, 120 and 200 g/kg of carbohydrates (C0, C120 and C200, respectively) for 10 weeks. Results showed that higher dietary carbohydrate intake enabled further deposition of glycogen and lipids in liver and muscle. The mRNA levels of glucokinase (gck), phosphofructokinase (pfkl) and hexokinase (HK) activity involved in glycolysis were significantly up‐regulated in C120 (p < .05) but showed no further up‐regulation except for gck in C200. Besides, the gluconeogenic phosphoenolpyruvate carboxykinase 1 (pck1) mRNA levels were down‐regulated significantly in fish fed the C120 (p < .05). However, further increase in dietary carbohydrate levels increased the mRNA levels and activities of enzymes involved in gluconeogenesis and lipolysis (p < .05). Additionally, plasma glucose remained unchanged in C120 (p > .05) but significantly increased in C200 group (p < .05). In conclusion, Japanese flounder was able to use carbohydrates efficiently through regulation of glucose and lipid metabolism when dietary carbohydrate was not higher than 120 g/kg, while 200 g/kg of dietary carbohydrate caused the deregulation of glucose homoeostasis.     

意大利苍耳的化感作用对油葵种子萌发的影响

实验在严格受控条件下研究了意大利苍耳不同器官的水浸提液对油葵种子萌发的影响,以评价在种子萌发阶段意大利苍耳对油葵的化感抑制潜力。结果表明,意大利苍耳各器官的水浸提液均对油葵种子萌发产生了强烈的、具有浓度和器官依赖性的化感抑制效应,随着浸提液浓度的提高,化感抑制活性显著增强;与根和茎相比,叶片和果实的化感抑制活性更强。意大利苍耳不同器官水浸提液不仅减缓了油葵种子的萌发速度、推迟了种子的萌发时间,而且显著地降低了油葵种子的萌发率;其中在100 g·L^-1浓度的根、茎、果实、叶片水浸提液中,油葵种子14 d的累积萌发率较对照组分别下降了27%、48%、53%和78%。因此,意大利苍耳凋落物和残茬的化感抑制作用所造成的油葵种子的萌发变缓、萌发延迟以及萌发失败,可能是导致油葵大量缺苗的重要原因之一。     

水旱轮作防控福寿螺的效果及对水稻产量的影响

【目的】探索2种冬种作物水旱轮作对来年早稻田福寿螺的控制效果及对水稻产量的影响.【方法】对冬种马铃薯和冬种黑麦草这2种控螺方式下前后茬稻田中福寿螺种群和后茬水稻产量进行调查,并与冬闲干田和冬闲淹水处理的前后茬稻田进行对比.【结果和结论】冬种马铃薯能够有效减少来年早稻田福寿螺的发生量,且能提高来年早稻产量,但早稻生长后期福寿螺种群恢复速度加快.冬种黑麦草处理的控螺效果不理想,但有利于来年早稻增产.冬种水旱轮作模式下对福寿螺卵块的控制效果不明显,但在来年早稻种植的初期,绝大部分卵块产在田埂杂草上且数量较少,此时人工摘卵较为方便省时.     

黑穗醋栗(Ribes nigrum L.)种子发育、结构及鲜种子播种的研究

观察黑穗醋栗(Ribes nigrum.L.)种子发育及成熟种子解剖特征表明,珠被发育成种皮过程中,外珠被表皮细胞异常膨大。胚发育缓慢,原胚初期常有不规则现象。胚乳发生属细胞型。初生胚乳核分裂后,由合点端向珠孔端逐渐形成细胞,胚乳发育中,后期有“区域性”分化现象。成熟种子种皮属浆果皮类型。胚较小,直立型,位于种子基部,果实成熟后立即播种,有30%左右种子萌发,当年成苗,对缩短育种周期有一定价值。     

薏苡脱壳机关键部件作业参数优化与试验

针对薏苡脱壳设备脱净率差、破碎率高,相关工艺与装备研究几近空白的现状,该文结合薏苡物料特性,运用中心组合试验设计理论开展关键部件作业参数试验与优化,重点研究薏苡脱壳机脱壳仓作业关键参数中动盘转速、动静磨盘间隙、静盘工作面宽度对脱净率、破碎率的影响规律,并以脱净率、破碎率为响应指标进行多目标优化。首先对主产区主要薏苡品种物料特性进行研究,并进行与脱壳相关的物理参数测定,然后采用二次正交旋转组合试验方法设计试验并用Design-Expert进行数据处理,建立脱净率、破碎率的回归数学模型并进行方差分析。分析得出影响薏苡脱壳机脱净率的主次因素依次为:动盘转速静盘工作面宽度动静磨盘间隙;影响破碎率的主次因素依次为:静盘工作面宽度动静磨盘间隙动盘转速。通过响应曲面方法分析各因素交互作用对脱净率、破碎率的影响,并根据优化目标的重要程度(脱净率较破碎率重要)对回归模型进行多目标优化,得出薏苡脱壳机关键部件最佳作业参数组合为:动盘转速1 076.02 r/min,动静磨盘间隙4.91 mm,静盘工作面宽度7.63 mm。此时,脱壳机脱净率最高、破碎率最低,其值分别为50.49%、3.02%。将优化参数在薏苡脱壳设备上开展验证及批量化流水加工作业,流水加工作业脱净率达51.1%、破碎率3.6%,设备作业质量大幅提升,达到了较为理想的效果。该研究可为提升薏苡脱壳机作业质量提供参考。     

Selection and characterization of ssDNA aptamers specifically recognizing pathogenic Vibrio alginolyticus

Vibrio alginolyticus (V. alginolyticus) is a major opportunistic pathogen to both marine animals and humans, which has also caused heavy economic losses to mariculture. The aim of this study was to develop highly specific aptamers for V. alginolyticus. Single‐stranded DNA (ssDNA) aptamers with high binding affinity to viable V. alginolyticus were generated by Systematic Evolution of Ligands by Exponential Enrichment (SELEX) and identified by flow cytometric analysis in this study. The selected aptamers showed high specificity for V. alginolyticus and low apparent binding for other bacteria. The aptamers formed distinct stem‐loop structures, which could form the basis of aptamers’ specific binding to the target V. alginolyticus. Aptamer VA2 and VA8 showed particularly high binding affinity constant (Kd) of 14.31 ± 4.26 and 90.00 ± 13.51 nM, respectively. The aptamers produced no cytotoxic effects in vitro and in vivo. ssDNA aptamers were successfully selected against the viable bacteria pathogen V. alginolyticus by SELEX. The aptamers selected in this study could be not only applied as specific chemical molecular probes for studying V. alginolyticus pathogenesis to Trachinotus ovatus, but also developing rapid convenient diagnosis assay for V. alginolyticus infection, even when applied to the complex sample matrix, such as food and environment samples.     

梭子蟹单筐养殖自动投饲系统设计与试验

为解决梭子蟹单筐养殖模式下的自动投饲问题,设计了一套轨道式自动投饲系统。自动投饲系统由行走系统、投饲机、供电系统和控制系统组成。在单片机系统的控制下,行车由直流电机驱动在轨道上行走,当行车上的定位传感器感应到养殖筐边沿上的定位识别板后,投饲机对一排养殖筐同时下料。当行车走到轨道末端时,行程开关可控制行车停止前进,避免行车脱轨。试验结果表明:自动投料系统实现了定量定位自动下料,称料误差在0.3 g以内,投料精度为97%,定位识别率为100%。当水位在0.5 m范围内变化时,定位误差小于3.5 cm,满足梭子蟹单筐养殖自动投喂的要求。     

不同糖源饲料对卵形鲳鲹(Trachinotus ovatus)生长、体组成、血糖水平和肝脏糖酵解酶活力的影响

分别以葡萄糖、蔗糖、糊精、玉米淀粉和糊化玉米淀粉为糖源配制成5种等氮等脂饲料,对初始体重为(31.24±0.58) g 的卵形鲳鲹(Trachinotus ovatus)进行为期56 d 的饲养实验,比较不同糖源饲料对卵形鲳鲹生长、体组成、血液指标和糖酵解酶活力的影响,筛选出最有利于生长的糖种类。结果显示,不同糖源对卵形鲳鲹增重率(WG)和特定生长率(SGR)均有显著影响(P<0.05),且随糖分子量增大有增大的趋势,其中,糊化玉米淀粉的 WG 和 SGR 最高分别为335.35%和2.62%/d;不同糖源组的脏体比(VSI)、肝体比(HSI)、肝糖原和肌糖原含量以及血糖、血浆总胆固醇和甘油三酯也有显著性差异(P<0.05),且均为葡萄糖组最高;除己糖激酶(HK)活力外,各糖源组的其他糖酵解酶活力均有显著性差异(P<0.05),亦是葡萄糖组最高。在本实验条件下,卵形鲳鲹对淀粉类大分子糖的利用效果优于葡萄糖等小分子糖类,糊化玉米淀粉组的生长效果最好;不同糖源饲料对卵形鲳鲹糖代谢过程中糖原合成、糖脂转化、糖酵解等途径的相关指标有一定影响。