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991.
大眼金枪鱼(Thunnus obesus)是最具经济价值的热带金枪鱼类,其资源状况一直是区域性金枪鱼渔业管理组织关注的重点。由于多种渔业作业、捕捞船队构成复杂,印度洋大眼金枪鱼的历史渔获量统计存在一定的偏差(Bias),但国际上近些年开展资源评估时都忽略了这一偏差。本研究根据1979~2015年的年渔获量、年龄结构渔获量及相对丰度指数数据,运用年龄结构资源评估模型(ASAP)对印度洋大眼金枪鱼资源进行评估,重点考查渔获量的不确定性(观测误差和统计偏差)对资源评估结果的影响。结果显示,印度洋大眼金枪鱼当前资源总体没有过度捕捞,但2015年初显示轻微的过度捕捞,通过对比基础模型与8个灵敏度分析模型的评估结果发现,渔获量观测误差(CV)的预设对资源开发状态的判断有一定的影响。当渔获量统计偏差调整量为15%时(即历史渔获量被低估了),评估结果与基础模型基本一致;统计偏差调整量为20%时,评估结果有过度捕捞的趋势。本研究结果表明,资源评估模型中渔获量观测误差的设定和历史渔获量统计偏差均会对评估结果产生影响,后者更为明显,因此,二者均不能忽略。  相似文献   
992.
993.
This study evaluated the effects of Aurantiochytrium spp. microalgae meal and oil as dietary docosahexaenoic acid (DHA) sources on the growth, fatty acid composition and DHA retention of orange‐spotted grouper, Epinephelus coioides. Dietary fish oil was replaced with microalgae meal or oil to provide an equal amount of DHA as a fish oil‐containing basal diet. In total, three experimental diets were fed to triplicate groups of fish (initial wt: 8.48 ± 0.06 g) in a recirculating system for 8 weeks. The weight gain and feed efficiency of the fish did not differ significantly among the experimental diets. The fatty acid composition of the whole body of the fish generally reflected the composition of their diet. The concentration of eicosapentaenoic acid in the whole body was higher in the fish fed the fish meal control diet than in those fed the two experimental diets The fish fed the control diet and those fed the diet containing microalgae oil exhibited higher DHA concentrations than did the fish fed the diet containing microalgae meal. The whole‐body DHA retention was the highest in the fish fed the diet with microalgae oil, followed by the fish fed the control diet. The lowest whole‐body DHA retention was observed in the fish fed the diet containing microalgae meal. The results suggested that the oil from Aurantiochytrium spp. microalgae can be used as DHA source for the grouper. DHA utilization by the fish was higher when the diet was supplemented with microalgae oil than with dry microalgae meal.  相似文献   
994.
A newly synthetic allopolyploid strain (SAS) was selected and established from gynogenetic offspring of gibel carp clone A+ with 156 chromosomes induced by common carp sperm with 50 chromosomes. In this study, the allopolyploid strain was detected to contain 206 chromosomes, and the growth trait was evaluated to have 25.15% growth faster than that of clone A+. Genetic marker analyses of transferrin (Tf) alleles, ITS1 sequences and mtDNA D‐loop sequences indicated that the allopolyploid strain was synthetized from maternal gibel carp clone A+ and paternal common carp, and the synthetic chromosome sets were further confirmed by genomic in situ hybridization (GISH) and chromosome localization of 45S rDNA. Significantly, the synthetic allopolyploid strain has tended to be stable by five successive generations of gynogenesis, because it still keeps unisexual reproduction mode of gynogenesis. Therefore, it will become a novel variety for gibel carp aquaculture in future.  相似文献   
995.
 柑橘黄化脉明病毒(Citrus yellow vein clearing virus,CYVCV)是我国新发生的危害柠檬的重要病毒。本研究对接种和未接种CYVCV的柠檬叶片样品进行了高通量小RNA测序,以甜橙基因组作为参考,采用生物信息学软件进行miRNA鉴定和靶基因预测。结果显示CYVCV侵染对13个保守miRNA和12个新鉴定的非保守miRNA的表达具有调控作用,对这些差异表达miRNA的靶基因进行预测和功能分析的结果显示,保守miRNA的靶基因功能在植物逆境反应及光合作用和能量代谢相关通路中具有明显的富集现象,推测与CYVCV侵染柠檬植株及诱导病害症状表现有关,而多数新鉴定的非保守miRNA的靶基因功能未能注释到KEGG通路。采用实时荧光定量PCR对部分miRNA的表达水平进行了分析,结果表明miRNA的表达水平在接种CYVCV后30~90 d呈时间动态变化。研究结果为进一步揭示CYVCV与柠檬互作机制提供了重要信息。  相似文献   
996.
绿僵菌防治草原蝗虫效果显著,其在草原田间的存活能力影响其持续控害效果。除了侵染昆虫,绿僵菌还具有在植物根际宿存和根内生的生活方式,但相关宿存规律和内生性的研究报道很少。本文研究了绿僵菌在内蒙古草原两种优势种植物羊草和克氏针茅根际的种群数量变化并对其在这两种草的根内宿存进行了鉴定。结果表明,在干旱的内蒙古草原,绿僵菌施用后种群数量在30 d内快速下降,但能够以低密度在羊草、克氏针茅根际土壤中至少延续宿存75 d,羊草根际环境比较利于绿僵菌生存。对菌株egfp基因标记的特异PCR检测证明了绿僵菌在羊草和克氏针茅根内宿存。试验数据为指导植保生物防治中充分利用绿僵菌的昆虫病原性和植物内生特性提供理论基础,也将成为绿僵菌物种生活方式多样性、与植物互作及共进化研究的重要基础。  相似文献   
997.
This study reports a strain of Trichoderma harzianum CCTCC-SBW0162 with potential to enhance biocontrol activity against gray mold pathogen, Botrytis cinerea, and with a pivotal role in tomato (Solanum esculentum) plant growth enhancement. A total of 254 Trichoderma isolates were screened by in vitro antagonistic assay. Of these, 10 were selected for greenhouse experiments based on their greater inhibition of B. cinerea. The in vitro antagonistic assay and greenhouse experiments indicated that T. harzianum CCTCC-SBW0162 gave the highest inhibition rate (90.6%) and disease reduction (80.7%). Also, to study the possible mechanism associated with antifungal activity of CCTCC-SBW0162 against B. cinerea, molecular docking was used to assess the interactions between CCTCC-SBW0162-derived metabolites, and pathogencity and virulence related proteins of B. cinerea. The molecular docking results indicated that the combination of harzianopyridone, harzianolide and anthraquinone C derived from CCTCC-SBW0162 could synergistically improve antifungal activity against B. cinerea through the inhibition/modification of pathogenicity and virulence related proteins. However, this computerized modeling work emphasized the need for further study in the laboratory to confirm the effect T. harzianum-derived metabolites against the proteins of B. cinerea and their interactions.  相似文献   
998.
TaGAMyb是赤霉素合成途径中的一个转录因子。TaGAMyb-B在小麦中存在TaGAMyb-BaTaGAMyb-Bb两个等位变异。为了探讨这两种等位变异与小麦株高和第二节间细胞长度的关系,以93份春小麦育种材料的自然群体为对象,在2015和2016年对株高、第二节间细胞长度及两种等位变异进行了检测分析。结果表明,在这个春小麦自然群体中,分别属于TaGAMyb-BaTaGAMyb-Bb等位基因型的平均株高分别是73.43和68.93 cm,其差异显著(P<0.05)。第二节间中,TaGAMyb-Ba基因型材料转录本的表达量及节间厚壁组织细胞的长度均大于TaGAMyb-Bb基因型材料。所以, 推测TaGAMyb-Ba对春小麦第二节间伸长生长具有正向调控作用。  相似文献   
999.
In this paper, a silane coupling agent, 3-aminopropyltriethoxysilane, was reacted with nano-TiO2 to introduce amino group onto it which was then reacted with trichlorotriazine to obtain a dichlorotriazine functionalized nano-TiO2 for the firm fixation of it on cotton fibers. The reaction process was monitored by the titration of primary and secondary amino groups, and the reaction conditions were optimized with orthogonal method accordingly. The dichlorotriazine functionalized nano-TiO2 was reacted with cotton fabric by the nucleophile substitution reaction to afford nano-TiO2 functionalized cotton fabric, the structure and surface morphology of the nano-TiO2 finished cotton fibers were studied by FT-TR and SEM. In addition, the fixation duration of the nano-TiO2 modified cotton was studied according to AATCC test method 61–2010. The results show that the washing fastness of the nano-TiO2 is excellent.  相似文献   
1000.
为评价草甘膦对河口及滩涂水域生物的影响,采用室内人工染毒法,研究了草甘膦铵盐对可口革囊星虫Phascolosoma esculenta、缢蛏Sinonovacula constricta Lamark和大弹涂鱼Boleophthalmus pectinirostris 3种滩涂动物超氧化物歧化酶 (SOD)、过氧化氢酶 (CAT)、丙二醛 (MDA) 及大弹涂鱼红细胞微核的影响。结果表明:经低浓度 (63.5 mg/L) 草甘膦短时间 (2 d) 染毒后,可口革囊星虫肠组织的SOD、CAT活性值及MDA含量分别为231.54、1.719 U/mg pro. 和0.60 nmol/mg pro.,3种指标均显著或极显著高于相应对照值 (204.88、1.521 U/mg pro. 和0.54 nmol/mg pro.),且随着药剂处理浓度增加,SOD、CAT活性及MDA含量均升高;但当染毒时间延长至8 d时,可口革囊星虫肠组织的SOD、CAT活性值及MDA含量均明显降低,分别为155.67、1.403 U/mg pro. 和0.53 nmol/mg pro.,显著低于对照,且随药剂处理浓度进一步增加,酶活性及MDA含量值降低更显著。草甘膦对缢蛏内脏团及大弹涂鱼肝脏SOD、CAT活性及MDA含量的影响表现出类似规律。此外,经低浓度 (53.5 mg/L) 草甘膦染毒8 d后,大弹涂鱼红细胞微核率及核异常率分别为17.00‰ 和21.33‰,均极显著高于相应对照值 (13.67‰ 和13.33‰),且随着草甘膦浓度增大,其红细胞微核率及核异常率均显著升高,表明大弹涂鱼对草甘膦有较高的敏感性。所得研究结果可为评价草甘膦对河口及滩涂水域生物的影响提供参考依据。  相似文献   
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