两种盐度下凡纳滨对虾饲料中的最适动植物蛋白比

试验研究了不同盐度下（3和22）,以鱼粉和大豆浓缩蛋白为蛋白源,配制6种不同动植物蛋白比的饲料对凡纳滨对虾生长、成活和肝胰腺可溶性蛋白质含量的影响,饲养试验为期40 d。结果显示：（1）饲料动植物蛋白比可显著影响凡纳滨对虾增重率、成活率、肝体指数、肥满度和肝胰腺中可溶性蛋白质含量。增重率随饲料动植物蛋白比升高而升高,但当饲料中动植物蛋白比升至29∶8时,增重率不再明显升高,其它指标均先随饲料动植物蛋白比升高至一定程度,而后则稍有下降;（2）盐度22组对虾的增重率、成活率和肥满度显著高于盐度3组对虾,肝体指数却显著低于盐度3组,不同的盐度对凡纳滨对虾肝胰腺可溶性蛋白含量的影响不显著;（3）双因素方差分析结果显示,盐度和饲料动植物蛋白比对凡纳滨对虾增重率、成活率和肝体指数存在显著交互作用,最大值分别出现在盐度22下全动物蛋白饲料组、盐度22下全动物蛋白和动植物蛋白为29∶8的饲料组、盐度3下饲料动植物蛋白比为14∶23的饲料组中;（4）Broken-Line分析表明,3‰盐度下凡纳滨对虾最适饲料蛋白比为29.12∶7.79~30.29∶6.71,盐度22时为26.05∶10.95~29.03∶7.44。结果提示,饲料中氨基酸的组成和含量会随配方中动植物蛋白配比而改变,且不同盐度下凡纳滨对虾对饲料中动植物蛋白比的要求有所不同,但配饵中适当的动植物蛋白比可以满足虾对各种氨基酸的适宜需求。因此,在养殖过程中,需结合实际的养殖环境和饲料蛋白源种类,来设计适宜的实用饲料配方,这样才能达到降低生产成本,提高经济效益的目的。     

绿原酸诱导凡纳滨对虾抗氧化功能及抵御低盐度胁迫的响应

选择健康、均匀, 体质量为(6.74 ± 0.08) g的凡纳滨对虾(Litopenaeus vannamei),  将360尾随机分为4组, 分别投喂含有0 mg/kg、100 mg/kg、200 mg/kg和400 mg/kg绿原酸的饲料28 d, 随后将对虾从盐度为32的天然海水直接转移至盐度为10的海水中暴露72 h, 测定对虾肝胰腺TAS、GPx、CAT活力和GPx、CAT基因表达水平。结果显示, 在天然海水养殖条件下, 绿原酸对凡纳滨对虾肝胰腺TAS、GPx活性无明显影响, 但投喂含有绿原酸的饲料28 d, 对虾肝胰腺GPx、CAT和GPx、CAT基因表达水平显著高于D0组(P<0.05), 以D2组GPx活性和GPx、CAT基因表达水平最高, 分别为164.29 U/mgprot和1.61、2.14倍。低盐度胁迫24 h, D0组对虾抗氧化反应表现在TAS、GPx活性和GPx基因表达水平较28 d显著升高(P<0.05), 分别增加了31.30%、27.96%和170%, 而绿原酸各组对虾肝胰腺TAS、GPx活性和GPx基因表达水平显著低于D0组(P<0.05), 说明绿原酸可有效缓解低盐度胁迫下对虾抗氧化系统酶活性的剧烈波动。低盐度胁迫72 h, 绿原酸各组对虾肝胰腺TAS、GPx、CAT活性及CAT基因表达水平均明显高于D0组。上述结果表明绿原酸能够诱导凡纳滨对虾的抗氧化系统功能, 在凡纳滨对虾抵抗低盐度胁迫中发挥着重要的作用。本研究旨为开发绿色植物提取物在对虾养殖中的应用, 解决盐度胁迫对机体造成的氧化损伤提供理论依据。

     

Application of biochar in mitigation of negative effects of salinity stress in wheat (Triticum aestivum L.)

Salinity is a major abiotic stress that affects crop production throughout the world. Biochar is an activated carbon soil conditioner that can alleviate the negative impacts of salinity. The research was conducted to evaluate the ameliorative effect of 1% and 2% of biochar application on wheat seed germination and growth attributes under salinity. Both levels of biochar improved the germination and growth conditions under salinity; however, 2% biochar level was more effective compared to 1% level. Root and shoot length increased up to 23% and11% with 2% biochar, respectively. The maximum increase of 16% and 10% in leaf water potential and osmotic potential was noted with 2% biochar at 150 mM salt. The decrease in proline content and soluble sugar at 2% biochar was 51% and 27%, respectively. Decrease in superoxide dismutase activity was 15.3% at 2% level of biochar under stress biochar mitigates the negative effects of salinity and improved wheat productivity.     

Effect of nutrient solution salinity and ionic concentration on parsley (Petroselinum crispum Mill.) essential oil yield and content

The growth and essential oil (EO) production of parsley were evaluated in response to salinity and nutrient solution concentrations in a soilless culture. Parsley plants that were 60 days old were potted in a coconut fiber and peat moss medium and were treated with four different nutrient solutions, including T1, T2, T3 and T4. The T1 nutrient solution was the standard, the T2 and T3 solutions contained incremental macronutrient concentrations with an electrical conductivity (EC) of up to 2.2 and 3.2 dS m^?1, respectively, and the T4 solution was the same as T2 but with sodium chloride (NaCl) and an incremental macronutrient concentration with an EC of 3.2 dS m^?1. Next, these plants were grown for 90 days in a greenhouse with natural daylight in Nador, Morocco. Shoot and root growth significant decreased with increasing EC. However, the salinity that resulted from the addition of NaCl did not affect plant growth in the nutrient solutions. The optimum obtained growth and EO production were 1.2 and 2.2 dS m^?1, respectively. Consequently, the optimum EC value (based on the EO production) of parsley in the soilless culture was 1.2–2.2 dS m^?1.     

Effects of different levels of soil salinity on yield attributes,accumulation of nitrogen,and micronutrients in Brassica spp.

The present study was conducted to assess the effect of soil salinity on yield attributes as well as nutrient accumulation in different plant parts of seven Brassica cultivars from two different species raised in pot culture experiment with two levels of salinity treatments along with control corresponding to soil electrical conductivity (EC) values of 1.65 (S₀), 4.50 (S₁) and 6.76 (S₂) dS m^?1. The experiment was consisted of twelve replications in a completely randomized design. Imposition of salinity stress affected various yield attributing characters including plant height, which ultimately led to severe yield reduction. However, tolerant cultivars, CS 52 and CS 54 performed better under salt treatment showing lesser yield loss. Salinity stress reduced the nitrogen (N) content in leaves of the Brassica plants, which reflected in decreased seed protein content. Reduced accumulation of iron (Fe), manganese (Mn) and zinc (Zn) was observed in leaf, stem and root at flowering and post-flowering stages, while CS 52 and CS 54 showed less reduction than susceptible cultivars under salinity stress.     

激光平地改善土壤水盐分布并提高春小麦产量

为了促进激光平地技术的应用与推广,在河套灌区以普通畦田为对照,分期、分段测定了激光平地畦田0～80 cm土层土壤水分、土壤盐分及春小麦生长状况。结果表明,从渠口到畦尾,激光平地畦田不同地段的土壤水分在春小麦生长的不同时期无显著差异,但从拔节期开始,上层土壤盐分逐渐升高;普通畦田从三叶期开始,上层土壤水分、盐分逐渐提高,且显著或极显著高于激光平地。普通畦田从三叶期开始,激光平地从拔节期开始,从渠口到畦尾,春小麦的生长状况逐渐变差,千粒质量、产量均逐渐降低,但激光平地的春小麦千粒质量、产量高于普通畦田。激光平地改善了畦田的土壤水分、盐分分布,促进了畦田中后段的春小麦生长,提高了畦田中后段的水分利用率及产出率。     

基于电磁感应的典型干旱区土壤盐分时空变异快速诊断

选取南疆典型干旱区研究其土壤盐分时空变异,在研究区域选取校正点测定表观电导率(ECa),并同时采集土壤样品,研究表明土壤盐分含量与大地表观电导率具有良好相关性(R =0.935),可由此建立土壤盐分电磁感应解译模型.构建移动式磁感调查系统对研究区域进行调查,获取足量表观电导率信息,结合GIS和地统计等相关知识研究土壤盐...     

银川平原土壤盐分及盐渍土的空间分布格局

系统认识和掌握盐渍土的空间分布特征,是治理改良盐渍土的基础。在总面积约6 184.9 km2的银川平原引黄灌区布设101个采样点,分层（0～180 cm）测定了土壤全盐量,应用地统计学方法结合GIS技术对其空间分布特征进行了研究。结果表明,银川平原各层土壤盐分的分布类型均比较复杂,呈高度的偏态分布。土壤盐分的变异属于中等变异强度。0～120 cm土层盐分的空间相关距离一般在20～28 km;而深层（＞120 cm）土壤的空间相关距离较大,约34 km。银川平原表层土壤属于非盐化土、轻度、中度、重度盐渍土和盐土的土地面积分别为0、1 508.8、3 614.9、982.6和78.6 km2,总体属于中度和轻度盐化土类型,且呈现一定的盐分表聚趋势。重度盐渍土和盐土主要分布在银北的石嘴山市、平罗县、惠农县一带和银南的部分地区。总体来说,银川平原的土壤盐渍化现象依然严重,应加强研究与治理改良。     

干旱区土地盐渍化时空动态变化及影响因子分析

土壤是人类社会及一切社会活动的基本条件,而土壤盐渍化是土壤退化和土壤荒漠化的重要类型之一,是当今干旱区发展中面临的重要问题之一,也是影响干旱半干旱区农业生产的第一障碍性问题。土壤盐渍化时空动态变化研究是发展土壤监测研究及估算方法的重要基础工作。因此盐渍化治理工作的好坏也成了人们关注的问题。文章以新疆塔里木盆地北缘渭干河-库车河三角洲绿洲为研究区,采用1989年9月25日及2001年8月1日的遥感影像,通过计算盐分指数,得到盐分指数图像,进一步将盐分指数图像参与其它波段进行分类,通过统计分析,研究了渭干河-库车河三角洲盐渍地动态变化状况和变化趋势,并对变化影响因素进行了分析。结果表明：非盐渍地有所减少,轻、微盐渍地有所扩大,年均扩大率3.37%,中度盐渍地和重度盐渍地都相应减少,而中度盐渍地减少较多,年均减少率分别为1.96%和1.09%;盐渍地时空变化是同时受自然和人文因素影响的复杂过程,其中人为因素的影响最大。虽然盐渍化治理工作取得了一定的成就,但干旱区盐渍化防治工作需要进一步努力和加强。     

提高河蟹期仔蟹成活率的关键技术

河蟹仔蟹培育成活率低的重要原因是盐度不适,全淡水环境不利于蟹幼体对渗透压的调节。本试验用08%盐度人工海水培育幼体,其期仔蟹成活率比对照组提高34倍。人工海水配方中的Mg2 浓度宜选400mgL左右。