新型缓控释增效肥研究进展和发展前景

传统肥料面临着利用率低、产能过剩等问题,新型缓控释肥通过新型包膜材料或者纳米技术,实现养分释放速度的可控性;通过添加信号物质,实现植物和化肥的互动,将植物养分需求规律作为主导因素,实现肥料的按需供给,达到减少化肥用量,提高肥料利用效率的目的。从定义、研发背景、分类及发展趋势等方面介绍了新型缓控释肥的研究进展,并对其未来发展进行了展望。     

开式离心纸浆泵叶轮流道内部流场PIV试验研究

为研究开式纸浆泵叶轮流道内纤维颗粒对液相流场的影响,采用透明有机玻璃材料制造模型样机,以清水和0.1%质量浓度的头发纤维悬浮液为介质,通过PIV试验对叶轮流道内的流动进行可视化研究.试验结果表明:当输送清水介质时,在大流量工况下叶轮流道内流动稳定,未出现旋涡和低速区;在小流量工况下,当叶轮流道旋转到蜗壳隔舌附近位置时,在叶轮流道中段压力面附近开始产生低速区,且低速区随着叶轮流道靠近隔舌位置和流量减小逐渐增大,在远离隔舌位置的叶轮流道内未产生明显的低速区;受叶片扭曲的影响,在叶轮流道内垂直于泵轴的不同截面上的相对速度大小不同,且随着叶片扭曲程度减小,相对速度差减小;输送头发纤维悬浮液介质时,在纤维颗粒的影响下,叶轮流道内的液相流动相对速度降低,导致在小流量工况下叶轮流道中段压力面附近低速区面积增大;在大流量工况下,纤维颗粒存在使液相流动的相对速度大小分布更均匀.     

无机碳源对零价铁介导的自养脱氮序批式反应器处理高氨氮废水的影响

无机碳源作为自养微生物的能量来源,是影响自养脱氮细菌富集的重要因素。文章通过添加不同量的KHCO3作为ZVI介导的自养脱氮体系中无机碳源,研究反应体系的脱氮效果影响趋势以及适宜的无机碳源添加量。结果如下:1)KHCO3作为无机碳源可以显著提高NH^+4-N去除率,KHCO3添加量越多,其NH^+4-N去除率越高。KHCO3添加量分别为2 g,1 g,0.5 g的SBR反应器R2,R1,R0.5的NH^+4-N去除率分别为98.39%,65.18%,44.56%,相较不添加KHCO3的R0分别提高86.5%,53.29%,32.67%。ZVI的添加会降低KHCO3对NH^+4-N氧化的促进作用。2)KHCO3可明显提高TIN去除效果,促进总氮脱除的高低顺序是R1>R0.5>R2,SBR反应器R2,R1,R0.5的平均TIN去除率分别为19.01%,32.04%,27.62%,相较于空白组R0分别提高了10.60%,23.63%,19.21%。3)KHCO3可中和硝化反应产生的H^+,对反应体系具有缓冲作用,可使微生物处于较适宜的酸碱环境中,更有利于反应器的稳定运行。4)适量的无机碳源KHCO3可以促进氨氧化细菌和厌氧氨氧化细菌的活性。该研究探讨了无机碳源在零价铁脱氮体系中的影响趋势,为铁型脱氮技术提供了理论支撑。     

大豆RING/U-box蛋白Glyma.13G115900的克隆及其对非生物胁迫的应答

课题组前期对干旱胁迫下大豆转录组的数据分析发现大豆Glyma.13G115900基因编码一个RING/U-box蛋白,其表达水平受干旱胁迫影响显著。本研究以垦丰16大豆为试验材料,克隆Glyma.13G115900基因。氨基酸多重序列比对表明其编码的蛋白与其它物种都具有高度保守的RING/U-box结构域。构建原核表达载体pET-29b-Glyma.13G115900转化到大肠杆菌中,Glyma.13G115900蛋白在大肠杆菌中能够表达。荧光定量PCR分析表明Glyma.13G115900基因的表达量受PEG、NaCl和ABA的影响显著,但基本不受冷胁迫的诱导。经PEG和NaCl处理后,该基因表达量与CK相比呈现出显著下降的趋势,PEG处理的表达量变化比NaCl下调的更明显;在ABA诱导下与CK相比该基因的mRNA丰度呈现出先上升后下降的趋势,在4 h表达量出现峰值,推测该基因可能通过依赖于ABA途径参与非生物胁迫应答。以上结果为进一步深入研究该基因的调控途径奠定基础。     

Impacts of diet on hindgut microbiota and short‐chain fatty acids in grass carp (Ctenopharyngodon idellus)

Diet is known to influence intestinal microbiota in fish, but the specifics of these impacts are still poorly understood. Different protein/fibre ratio diets may result in differing structures and activities of gut microbiota. We examined the hindgut microbiome of grass carp (Ctenopharyngodon idellus) fed three different diets: fish meal (FM, high protein – low fibre), Sudan grass (SG, high fibre – low protein) and compound feed (CF, intermediate). Microbial profiles of fish fed on FM were significantly different from profiles of fish fed CF and SG (F = 18.85, p < .01). Cetobacterium, known to be positively associated with protein digestion, was the dominant microbial group in FM samples (approximately 75.7%), while Lachnospiraceae and Erysipelotrichaceae, thought to be involved in fermentation of plant polysaccharides, were dominant in CF and SG samples (46.8% and 42.9% respectively). Network analyses indicated that the abundance of Lachnospiraceae and Erysipelotrichaceae was in a significantly positive correlation (r = .895, p = .001). Short‐chain fatty acid (SCFA) levels may indicate that the digestibility of diet by microbiota in the grass carp gut decreased from FM to SG (FM>CF>SG). Overall low SCFA levels indicate that hindgut fermentation probably provides a low proportion of energy requirements in grass carp.     

用液相色谱串联质谱法测定渔业水样中6种农药的含量

本文建立了一种快速检测渔业水质样本中酰胺类除草剂乙草胺、丙草胺、丁草胺、三嗪类除草剂莠去津、烟碱类杀虫剂噻虫嗪、三唑类杀菌剂苯醚甲环唑6种农药含量的液相色谱串联质谱法。采用乙腈-水-甲酸梯度洗脱、电喷雾电离方式、多反应监测模式测定考察检出限、线性范围、日内精密度及日间精密度。在三种加标浓度下,该方法的回收率为78.2%~104.7%。用液相色谱-四级杆-飞行时间质谱对疑似目标物质进行定性,用精确质量数、同位素丰度比和二级碎片解析方式等解析定性结构。该方法能够满足检测这六种农药的要求,能准确定性,自建的谱库可为渔业污染事故鉴定和水产品质量安全风险评估做支撑。     

夜间灯光数据DMSP/OLS在贫困地区亮化度模型构建中的应用

贫困县亮化度一定程度上反映着贫困县居民的生活水平发展状况,但与贫困区经济收入等相关指标的定量关系不太明确。针对该情况,提出了一种应用灯光数据的亮度统计数据,结合与贫困县经济收入等密切相关的经济规模指标、人口数量、财政收入等来定量研究贫困县亮化度模型,并选取样本贫困县对该模型进行验证。经数据验证,该模型具有较高的可信度。     

华南6水系与澜沧江-湄公河攀鲈线粒体ND2基因的遗传多样性分析

测定了中国华南6水系及澜沧江(云南勐腊)-湄公河流域(柬埔寨洞里萨湖)的125尾攀鲈(Anabas testudineus)线粒体部分ND2基因1 010 bp序列,分析发现39个变异位点和12个单倍型,总遗传多样性较低(h=0.369,π=0.003 8),推测可能经历过严重的瓶颈效应;中国攀鲈群体遗传多样性更低(h=0.282,π=0.000 4),处于边缘区的中国攀鲈群体是造成低遗传多样性的主要原因。在单倍型网络图中柬埔寨和中国攀鲈各自聚类,具有明显地理结构和谱系结构,推测地质运动和气候变化导致基因交流受阻所致。核苷酸错配图和中性检验表明中国群体经历过种群扩张,时间约为(5.94~4.13)万年前。华南水系群体间基因交流通畅,不存在明显分化;但与云南澜沧江群体间分化大而显著(FST=0.775,P0.01),AMOVA分析显示变异主要来自组群间(77.41%),推测二者分化时间约为(4.0~2.8)万年前,云南群体受末次冰期的影响,基因交流受阻而出现分化。中国群体和柬埔寨群体可作为2个管理单位进行保护;就中国群体而言,韩江水系群体遗传多样性最高,建议优先保护;澜沧江与华南水系间群体分化显著且遗传多样性极低,建议对澜沧江水系群体进行保护,以避免种质资源灭绝。     

Nutritional Qualities of the Low-Value Bivalve Mollusks Paphia malabarica and Villorita cyprinoides at the Estuarine Waters of the Southwestern Coast of India

The bivalve mollusks Paphia malabarica and Villorita cyprinoides collected from the estuarine system located in the southwest coastal waters of India were evaluated for their nutritional composition. A balanced essential to nonessential amino acid ratio (> 1.0) with a greater quantity of sulfur-containing amino acids in these species demonstrated that they could provide well-balanced protein depositions. The n-3/n-6 polyunsaturated fatty acid ratio in P. malabarica was found to be greater than 2, and, therefore, can be considered as a healthy diet. The C₂₀–C₂₂ long-chain polyunsaturated n-3 fatty acids (for example, docosahexaenoic acid and eicosapentaenoic acid) accounted for more than 23% of the total fatty acid content in P. malabarica as compared to about 7% in V. cyprinoides. P. malabarica showed greater hypocholesterolemic/hypercholesterolemic ratio (1.7) and lesser atherogenicity (0.7), thrombogenicity (0.3) indices when contrasted with those in V. cyprinoides, thereby indicating the nutritional superiority of the former. A greater content of vitamin D₃ (> 150 IU), along with significant quantities of calcium and phosphorus (> 500 mg/100 g) in the clams, signified their importance in preventing osteoporosis. This study demonstrated the importance of bivalves, in particular, P. malabarica as a valued species for human consumption.