3种品系尼罗罗非鱼(Oreochromis niloticus)盐碱耐受性和生长比较

为评估尼罗罗非鱼的耐盐碱性能,分别测定了上海、山东、河北3种品系尼罗罗非鱼鱼种96 h的半致死盐、碱度,并在不同盐碱混合浓度(S0A0、S10A0、S10A2、S10A4、S10A6)中进行为期60 d的养殖生长比较。单盐、单碱耐性研究表明,上海、山东、河北3种品系尼罗罗非鱼鱼种的96 h半致死盐度分别为18.528 g/L、20.347 g/L、19.342 g/L,96 h半致死Na HCO3碱度为8.827g/L、8.540 g/L、8.542 g/L。盐碱混合条件下,盐度为10时,96 h半致死碱度分别为河北品系(4.377g/L)上海品系(3.561 g/L)山东品系(3.108 g/L),品系之间差异显著(P0.05);盐度为15时,96 h半致死碱度分别为河北品系2.144 g/L,上海品系2.183 g/L,山东品系2.183 g/L,品系之间无显著差异(P0.05),高盐度下尼罗罗非鱼鱼种的碱度耐受性明显低于低盐度下的碱度耐受性。结果表明,尼罗罗非鱼日均增重率在S0A0、S10A0组间无显著差异(P0.05),随着盐碱浓度增加,盐碱S10A4和S10A6组中日均增重率呈下降趋势,河北品系表现出相对生长优势(P0.05)。研究结果为尼罗罗非鱼适宜养殖的盐碱范围的确定、耐盐碱品系的筛选提供了基础资料。     

钴—60辐照对石花菜琼胶质量影响

用钴—60辐照处理琼胶成品和干制石花菜。经钴—60辐照的琼胶成品,其凝胶强度均有所下降,其下降率与辐照剂量大小呈正比。石花菜经钴—60辐照后,可使琼胶提取率提高,但过高的辐照剂量,也同时会降低所制取琼胶的凝胶强度。通过适宜剂量的钴60—辐照处理干制石花菜,可提高琼胶提取率3％～5％,且制取的琼胶凝胶强度不受辐照的影响。     

广西工厂化循环水养殖石斑鱼水质处理效果

通过集成海水养鱼、生化处理、设施工程、环境工程、电器自控和水质监控等技术,建立一套适合广西地区应用的工厂化循环水石斑鱼养殖系统。该养殖系统处理流程为:鱼池→沉淀池→蛋白质分离器→生物滤池→海马齿浮床→紫外杀菌,生物滤池包括A、B、C三个通道,A、B通道均由珊瑚石作为一、二级生物过滤和生化球作为三级过滤,C通道由珊瑚石作为一级过滤和椰子壳碎作为二、三级过滤。结果显示:沉淀池处理可以显著降低鱼池的COD,氨氮、亚硝酸盐氮、硝酸盐氮和磷酸盐的质量浓度(P<0.05);经海马齿浮床系统处理后,硝酸盐氮质量浓度显著低于沉淀池、蛋白质分离器处理池、生物滤池A、B通道(P<0.05);整体上,C通道水质指标略低于A、B通道,但差异不明显(P>0.05)。该研究结果可为广西沿海发展循环水养殖技术以及养殖生产方式转变提供可靠的科学数据和技术参考。     

Characterization of Collagen Enzymatic Hydrolysates Derived from Lizardfish (Synodus fuscus) Scales

Acid soluble collagen was extracted from the scales of lizardfish and characterized with sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and amino acid analysis. After 8 h of collagen hydrolysis, hydrolysates had an estimated degree of hydrolysis (DH) from 4 ± 0.05 to 25 ± 0.63% (p < 0.05). All hydrolysates had angiotensin converting enzyme inhibitory and antioxidant activity. These activity levels showed little change after treatment with gastrointestinal proteases. Results indicated that the lizardfish by-products may be improved by enzymatic treatment with acid-soluble collagen from lizardfish scales.     

Constructed wetlands as a treatment method for effluents from intensive trout farms

This study examined the effects of different hydraulic loading rates on the treatment efficiency of subsurface flow (SSF) constructed wetlands treating effluents from trout farming over a period of 6 months. Six identical wetland cells with a pre-sedimentation zone of 9.6 m² and a root zone of 23.6 m² were loaded with effluents from intensive trout farming (> 2.1 kg feeding stuff per L/s and day). The total runoff of 13.2 L/s was treated in the wetland cells, where two duplicate cells received equal hydraulic loads of 3.9, 1.8 and 0.9 L/s. All examined wetland cells had significant treatment effects on the nutrient fractions containing particulate matter [total nitrogen (TN), total phosphorous (TP), biological oxygen demand in 5 days (BOD₅), chemical oxygen demand (COD), and total suspended solids (TSS)].

Efficiency was between 5.5% for TN and 90.1% for TSS. The SSF wetland also had a high treatment effect on total ammonia nitrogen (TAN), with efficiencies of 61.2 to 87.8%. Nitrate nitrogen (NO₃–N) and phosphate phosphorous (PO₄–P) showed a significant increase in the wetland effluent by 8.4 to 209%. Nitrite nitrogen (NO₂–N), had no significant, or significant effluent increase depending on the inflow rate. Treatment efficiency for particulate nutrients and TAN increased with decreasing hydraulic load, while the differences between 1.8 and 0.9 L/s were not significant. The treatment efficiency for TP was constant for all cells, at around 40%. The wetland receiving 3.9 L/s was over-flooded after 10 to 12 weeks due to colmatation. Nevertheless, the wetland still showed high treatment efficiencies. For commercial trout farms, SSF wetlands are a highly effective method of effluent treatment. A hydraulic load of 1 L/s on 13.3 m² wetland area (1.8 L/s on the examined wetland) seems most suitable. Higher loads lead to accelerated wetland colmatation, while lower loads waste space.     

EDTA对铅胁迫下萝卜芽苗菜生长的影响

以萝卜芽苗菜为材料,在其生长期外施不同浓度EDTA,初步探讨了EDTA对铅胁迫下萝卜芽苗菜部分生理生化特性的影响.结果表明:在300 mg/L铅胁迫浓度下萝卜芽苗菜的膜透性明显增大,过氧化物酶(POD)活性、超氧化物歧化酶(SOD)活性、可溶性蛋白含量明显下降.随着外施EDTA浓度的增加,萝卜芽苗菜的膜透性先下降后升高,过氧化物酶(POD)活性、超氧化物歧化酶(SOD)活性、可溶性蛋白含量先升后降.就供试材料而言,在一定浓度范围内的EDTA对铅胁迫萝卜芽苗菜的伤害效应有缓解作用,其中以0.75 μmol/L EDTA处理效果最为明显.     

不同贮前热处理对青种枇杷果实贮藏效应的研究

通过采用不同的贮前热处理温度和时间组合,研究白沙枇杷青种在低温条件下的贮藏的内外品质的变化.结果表明:3种贮前热处理中,B处理(45℃热水处理10 min+低温(6±1℃))的效果最好,不仅青种枇杷果实的失重率和腐烂率低;而且贮藏到30 d时,枇杷果实的固酸比最高,较好保持了果实的风味.     

遮荫处理对侧柏种子萌发的影响

在不同光照梯度55.44%自然全光照(Natural sonlight,NS)、21.12%NS、3.47%NS 和0.86%NS的人工遮荫条件下,研究了侧柏(Platycladus orientalis)种子萌发的特点.结果表明:4个光照梯度处理的侧柏种子的萌发率分别为68.9%、82.2%、44.4%和42.2%;随着光照强度的减弱,种子萌发进程减慢;萌发指数和幼苗活力指数均在21.12%NS处理最大,分别为1.89和770.8.     

猕猴桃辐射诱变效应的初步研究

用60Co-γ射线处理"和平红阳"和"和平一号"2个猕猴桃品种幼芽,并在猕猴桃成株上进行高位嫁接,对其辐射效应进行初步研究.结果表明:嫁接萌芽率变化的一般趋势是随着辐射剂量的加大而降低;随辐射强度的增加,使萌发芽的死亡率加大,导致最终成活枝的比例降低.参试品种的半致死剂量在50～75 Gy之间.辐射在引起猕猴桃幼芽生理损伤的同时,亦会诱发性状变异.2个品种的茎长、叶柄长、叶片宽等性状50 Gy处理和CK间的差异均达到显著水平,2 a试验取得一致的结果.而茎直径和叶片长度,不同品种及不同年份的表现不同.辐射处理会提高性状的变异系数,增加性状的变异度,为选择提供更丰富的变异材料.表明辐射诱变在猕猴桃品种改良中有重要的研究应用价值.     

低温胁迫对四种野生常绿藤本植物抗寒生理指标的影响

以鹰爪枫Holboellia coriacea、南五味子Kadsura japonica、尾叶挪藤Stauntonia obovatifoliola ssp. urophylla、山蒟Piper hancei等4种野生常绿藤本植物为试验材料,通过人工冷冻处理,对叶片的相对电导率、过氧化物酶(POD)活性和游离脯氨酸含量等3个生理指标进行了测定.结果表明:细胞膜透性表现为逐渐上升趋势;而过氧化物酶(POD)活性和游离脯氨酸含量则随着温度的降低呈现出先上升后下降的变化规律,低温下耐寒性强的种类能保持较高的POD活性.4种野生常绿藤本植物的抗寒性具有明显差异,其中以鹰爪枫抗寒能力最强,其次为南五味子和尾叶挪藤,山蒟抗寒能力最差.