丁香酚对降低罗非鱼捕捉应激的作用

摘 要：【研究目的】为了了解麻醉剂丁香酚对鱼类养殖的影响，适量麻醉是否可以降低操作带来的应激反应。【方法】通过对罗非鱼进行适量麻醉和无麻醉直接处理后，检测不同时间捕捉处理后罗非鱼血浆中皮质醇和乳酸动态变化，研究鱼用麻醉剂丁香酚对罗非鱼捕捉应激的影响。【结果】结果显示：在10~120 mg/L范围内，随着丁香酚药浴浓度的增加，罗非鱼麻醉时间逐渐缩短，苏醒时间逐渐增长，实验选取的最适麻醉浓度为45 mg/L。捕捉后0、30、60 min三个取样点，丁香酚处理组罗非鱼血浆中皮质醇浓度降低，但各时间点无显著性差异(P>0.05)，直接捕捉处理组皮质醇浓度显著增加(P<0.05)。0 min时处理组皮质醇浓度显著低于对照组，30、60 min时处理组极显著低于对照组(P<0.01)。捕捉后两个处理组0 min血浆中乳酸浓度无显著差异；直接捕捉处理组30 min和60 min血浆中乳酸浓度显著高于0 min(P<0.05)，且显著高于丁香酚处理组0 min、30、60 min三个取样点 (P<0.05)，丁香酚处理组血浆中乳酸浓度差异不大。【结论】结果表明：在理想麻醉剂量下，将罗非鱼使用丁香酚进行麻醉后捕捞、运输等操作，可避免捕捉后鱼体皮质醇和乳酸浓度的激增，有效降低罗非鱼的捕捉应激。     

丁香酚对细鳞裂腹鱼幼鱼的麻醉效果研究

探索丁香酚对细鳞裂腹鱼(Schizothorax chongi)幼鱼的麻醉效果,为其生产和分子取样等提供参考。采用静水法研究幼鱼在丁香酚溶液中,不同浓度、不同药浴时间、不同空气中暴露时间下细鳞裂腹鱼幼鱼麻醉与复苏情况。结果表明,丁香酚浓度与麻醉时间呈负相关,浓度与麻醉时间关系式：y₁=286.63e^-0.0135x,R²=0.9593;幼鱼复苏时间与丁香酚浓度呈正相关,浓度与复苏时间相关式：y₂=101.54e^0.0134x,R²=0.9913,不同浓度下幼鱼的麻醉时间和复苏时间均呈显著性差异(P<0.05),40 mg/L浓度丁香酚药浴中,幼鱼药浴时间与复苏时间呈正相关,复苏时间与药浴时间关系式：y=64.647x^0.2394,R²=0.9823,不同时长下复苏时间呈现显著性差异(P<0.05),40 mg/L浓度下,幼鱼在空气中暴露时长和复苏时间呈负相关,麻醉后的幼鱼在空气中的暴露时间与复苏时间的...     

不同麻醉剂对刺参幼参麻醉效果的比较研究

为了找到一种可以准确测量活体刺参体长的方法,我们研究了不同浓度及不同药浴时间条件下,硫酸镁、丁香酚和乙二醇苯醚等三种麻醉剂对仿刺参(Apostichopus japonicus)幼参(1.3815±0.2138) g的麻醉效果。试验结果显示：（1）乙二醇苯醚的麻醉效果最差,丁香酚在浓度较小(≤0.3 mol/L)时有一定的麻醉效果。当浓度过大时,二者都会对刺参造成伤害。硫酸镁在浓度为0.3~0.4 mol/L时麻醉效果最好,麻醉时间较快（约30 min）且麻醉率和苏醒率均达100%。（2）在0.3~0.4 mol/L的硫酸镁溶液中药浴1 h左右的刺参,其体长与药浴前的体长变化差异极显著,而药浴1、1.5、2 h的刺参个体间体长变化不显著。以上结果表明：0.3~0.4 mol/L的硫酸镁溶液对刺参的麻醉效果最好,既不影响刺参的正常生长又可准确测量其自然生长状态长度。通过本研究确定硫酸镁是刺参的最佳麻醉剂,用于刺参体长测量的最佳浓度和麻醉时间分别为0.3~0.4 mol/L 和 1 h。     

酶解制备日本沼虾游离精子方法的研究

为了获得数量多且存活的游离青虾精子,首次采用胰蛋白酶消化日本沼虾精荚的方法,获得了游离日本沼虾的精子。通过观察游离精子形态,并经台盼蓝染色,以每克精荚所获得形态正常、结构完整且不被染色的存活精子数为依据,探究胰蛋白酶处理的最佳条件。在p H 7.1的条件下,设计三因素四水平正交试验,设置不同酶浓度(0.2%、0.4%、0.6%、0.8%)、处理时间(5 min、10 min、15 min、20 min)和处理温度(30℃、35℃、40℃、45℃),根据正交试验结果确定酶处理最佳反应条件。结果表明,酶浓度对获得游离精子影响最大,其次是处理温度和处理时间。酶处理的最适条件为:酶浓度0.8%,处理时间10 min,处理温度40℃。经优化验证试验,表明上述理论组合确为最佳组合。本研究通过酶解法获得较多数量的存活游离精子,为进一步研究日本沼虾精子提供了获得游离精子的方法。     

亚硝酸盐胁迫下丁酸梭状芽孢杆菌对日本沼虾应激代偿的调节

以日本沼虾（Macrobrachium nipponense）为试验材料,研究了在亚硝酸盐的污染胁迫下,饲料中添加一定量的丁酸梭状芽孢杆菌（Clostridium butyricum）对试验沼虾的生长及肌肉组织中超氧化物歧化酶（SOD）和过氧化氢酶（CAT）活性的影响。研究结果表明,经21d的试验,添加1%和5%的丁酸梭状芽孢杆菌可显著提高沼虾的生长率、SOD和CAT的活性（P<0.01）,但2个添加组之间的差异不明显（P>0.05）。当养殖水环境中的亚硝酸钠浓度在0~0.50 mg?L-1范围内,试验组沼虾肌肉的SOD和CAT活性随着亚硝酸钠质量浓度和丁酸梭状芽孢杆菌添加量的上升而升高,在试验的第6~9d时达到峰值,随后又开始下降。至试验21d时,沼虾肌肉组织中SOD和CAT活性取决于水环境中亚硝酸钠的质量浓度和饲料中丁酸梭状芽孢杆菌的添加量。研究表明饲料中添加丁酸梭状芽孢杆菌不仅可促进日本沼虾的生长,而且还可以增加日本沼虾对亚硝酸盐污染胁迫的耐受和抵抗能力,其适宜的添加量为106个活菌数/克饲料。     

日本沼虾对碱性湖泊水含盐量的适应性研究

采用室内急性毒性实验法,研究日本沼虾对东北地区碱性湖泊水含盐量的适应能力,探讨碱性湖泊增殖与养殖日本沼虾的可能性。结果表明,在pH 为7.72~7.81、碱度7.87~14.49 mmol/L时,含盐量对幼虾毒性作用的24 h半数有效浓度为3.17 g/L,95%置信限3.02~3.32 g/L。在pH为 7.85~8.07、碱度16.97~26.96 mmol/L时,含盐量对幼虾毒性作用的24 h、48 h、96 h半数致死浓度分别为7.95、6.84、5.77 g/L,95%置信限分别为7.74~8.11、6.69~6.99、5.59~5.93 g/L。日本沼虾对东北地区碱性湖泊水含盐量的适应上限为3.69 g/L,耐受限8.65 g/L,耐受范围4.25~8.19 g/L,长期生存所适应的含盐量为1.52 g/L。碱性水环境下日本沼虾对含盐量的适应能力将下降。东北地区含盐量在4.0 g/L以下、碱度在10~30 mmol/L的碱性湖泊可以增殖与养殖日本沼虾。     

高温对磷化氢和二氧化碳混合熏蒸杀虫增速增效作用的研究

本实验在35℃、40℃和45℃3个不同温度条件下用磷化氢和二氧化碳混合熏蒸防治玉米象和米象，研究结果表明，当二氧化碳浓度为5％，磷化氢浓度为0.07mg/l,0.14mg/L和0.21mg/L时，温度的升高可以明显缩短害虫死亡时间，在45℃时，磷化氢在0.14mg/L以上，磷化氢和二氧化碳混合熏蒸在12－24小时之内能有效杀死受试玉米象和米象成虫。     

日本沼虾SRAP反应体系正交设计及优化

对影响SRAP反应的4个因素(Taq酶、dNTP、Mg2+、引物)4个水平进行正交组合,以建立日本沼虾的SRAP分子标记技术。试验分两步进行:第一步筛选出可有效扩增的引物组合;第二步对筛选出的体系进行优化。结果表明,日本沼虾SRAP反应体系适宜引物组合为Me4Em2,最适条件为在25μL的反应体系中,Mg2+、dNTP、Taq酶、引物浓度分别为2.5 mmol/L、0.25 mmol/L、0.64 U/20μL、0.6μmol/L。本研究结果为SRAP分子标记技术在日本沼虾中的应用奠定了基础。     

不同浓度赤霉素对伴娘山月桂种子萌发的影响

为探讨赤霉素及浸种温度对伴娘山月桂种子萌发的影响,本研究采用不同浓度赤霉素和不同浸种温度处理伴娘山月桂种子.结果表明,最适浸种温度为40℃＞20℃＞60℃;赤霉素浓度在0～500 mg/L范围内,浸种15 min和30min,分别以400 mg/L和300 mg/L处理最好,且发芽率、发芽势、发芽指数与对照组呈显著差异,萌发启动速度缩短.     

GA3和温度对醉蝶花种子发芽的影响

试验研究了不同GA3浓度和发芽温度对醉蝶花种子萌发的影响。结果表明:温度及GA3对醉蝶花种子发芽起始时间没有明显影响,各处理均于第3天开始发芽。GA3浸种可显著提高醉蝶花种子的发芽率和发芽指数,最佳浸种浓度为150mg/L。在本试验设定温度条件下(23℃和28℃),温度对醉蝶花种子发芽率和发芽指数没有明显的影响,但在28℃较高温度下可以缩短100～150 mg/L GA3处理的发芽时间。     

Avoidance of leaf rust fungi in wild relatives of cultivated cereals

Summary Avoidance of rust fungi that was based on poor appressorium induction was previously found in Hordeum chilense. In the present study 95 accessions of Triticeae were screened for avoidance of Puccinia hordei. The percentage of appressorium formation per germinated spore ranged from 6 to 90%. On none of the 41 accessions of Aegilops, Agropyron, Elymus, Secale, Thinopyrum or Triticum studied was the rate of appressorium formation lower than 25%. Lower rates of appressorium formation were, however, found on accessions of wild barley species Hordeum brachyantherum, H. marinum, H. parodii and H. secalinum. Its implications in cereal breeding are discussed.     

A note on the origin of Kalanchoë x vadensis Boom & Zeilinga (Crassulaceae)

Summary K x vadensis is a hybrid of K. blossfeldiana and K. marmorata obtained after doubling the number of chromosomes.     

Relation between wheat-rye crossability and seed set of common wheat after pollination with other species in the Hordeae

Summary Cultivars of common wheat (Triticum aestivum L. em. Thell.) of high wheat-rye (Secale cereale L.) crossability set more seed with pollen of other related species than did wheats of low wheat-rye crossability. This was found to be true for pollen parents from the genera Triticum, Aegilops, Secale, Agropyron and Elymus.     

Breeding apomictic bahiagrass (Paspalum notatum Flügge) with improved turf traits

The development of a turf‐type bahiagrass could have a remarkable impact on the billion‐dollar turf industry in the south‐eastern United States. The goals of this study were to (i) select bahiagrass genotypes with improved turf attributes and (ii) determine the reproductive mode and seed fertility of selected genotypes. The population included mutants, wild types, hybrids and standard cultivars evaluated at two locations for two years. Morphological variation was observed and clonal repeatability (H²) ranged from 0.27 to 0.90. Flowering was extremely reduced in some mutants, which also exhibited dark green colour, finer texture and reduced canopy height. Cytoembryological observations revealed that diploids reproduced sexually and tetraploids by obligate or facultative apomixis. Genotypes with superior seed fertility were identified, while others were comparable to the standard cultivars. While mutant plants exhibited great morphological variation, the random mutations did not affect their reproductive mode, validating the use of mutagenesis in apomictic species. The high H² indicated that selection for improved turf attributes could be successfully performed with the advantage of clonal seed propagation.     

Inheritance of fruit colour in a wild Russian red raspberry seedling

Summary A new gene, i, from a self-incompatible wild Russian Rubus idaeus seedling is described. The gene i interacts with the fruit colour gene T, Tii plants having apricot instead of red fruits, and spines, leaves and stems pigmented to varying degrees. A deficit of apricot-fruited seedlings in progenies segregating for i could be explained by linkage between i and the self-incompatibility S locus with a crossover value of approximately 26.7%.Segregations for spine colour in crosses and backcrosses of the Russian seedling with two green-spined (ttII) raspberries selected for their yellow fruit colour, showed that both the latter carried the spine colour intensifier gene P. This suggests that earlier authors were incorrect in attributing the apricot fruit colour developed by some tt plants to a pleiotropic effect of P.     

Flag Leaf Senescence, as Evaluated by Numerical Image Analysis, and its Relationship with Yield under Drought in Durum Wheat

Senescence was evaluated at different stages of the grain‐filling period in eight durum wheat varieties using numerical image analysis (NIA). The varieties were grown under early, severe drought conditions on the high plains of Sétif in Algeria. After flowering, three different irrigation treatments were applied. Treatment effect was small, while a genotypic effect was noted for most of the senescence parameters. Senescence correlated to biomass, while the maximal rate of senescence, V_smax, correlated to thousand‐kernel weight. The potential of the method of numerical image analysis for monitoring flag leaf senescence, detecting genotypic variability and selecting genotypes with delayed senescence is discussed.     

Mechanisms and diversity of resistance to sorghum shoot fly,Atherigona soccata

Sorghum shoot fly, Atherigona soccata, is one of the important pests of postrainy season sorghums. Of the 90 sorghum genotypes evaluated for resistance to this pest, RHRB 12, ICSV 713, 25026, 93046 and 25027, IS 33844‐5, Giddi Maldandi and RVRT 3 exhibited resistance in postrainy season, while ICSB 463, Phule Anuradha, RHRB 19, Parbhani Moti, ICSV 705, PS 35805, IS 5480, 5622, 17726, 18368 and 34722, RVRT 1, ICSR 93031 and Dagidi Solapur showed resistance in rainy season, suggesting season‐specific expression of resistance to A. soccata. ICSB 461, ICSB 463, Phule Yasodha, M 35‐1, ICSV 700, 711, 25010, 25019 and 93089, IS 18662, Phule Vasudha, IS 18551 and 33844‐5 and Barsizoot had fewer deadhearts than plants with eggs across seasons, suggesting antibiosis as one of the resistance mechanism. Five genotypes exhibited resistance with high grain yield across seasons. Correlation, path and stepwise regression analyses indicated that leaf glossiness, seedling vigour, trichome density, oviposition and leaf sheath pigmentation were associated with the expression of resistance/susceptibility to shoot fly, and these can be used as marker traits to select and develop shoot fly‐resistant sorghums.     

Cowpea (Vigna unguiculata): Genetics,genomics and breeding

Cowpea, Vigna unguiculata (L.), is an important grain legume grown in the tropics where it constitutes a valuable source of protein in the diets of millions of people. Some abiotic and biotic stresses adversely affect its productivity. A review of the genetics, genomics and breeding of cowpea is presented in this article. Cowpea breeding programmes have studied intensively qualitative and quantitative genetics of the crop to better enhance its improvement. A number of initiatives including Tropical Legumes projects have contributed to the development of cowpea genomic resources. Recent progress in the development of consensus genetic map containing 37,372 SNPs mapped to 3,280 bins will strengthen cowpea trait discovery pipeline. Several informative markers associated with quantitative trait loci (QTL) related to desirable attributes of cowpea were generated. Cowpea genetic improvement activities aim at the development of drought tolerant, phosphorus use efficient, bacterial blight and virus resistant lines through exploiting available genetic resources as well as deployment of modern breeding tools that will enhance genetic gain when grown by sub‐Saharan Africa farmers.     

Screening for resistance to take-all in wheat,triticale and wheat-triticale hybrid lines

Summary Fifteen triticale and wheat-triticale hybrid lines were evaluated for resistance to the take-all fungus Gaeumannomyces graminis var. tritici and compared with five wheat and two rye lines in inoculated field and pot trials. The triticale and wheat-triticale hybrid lines varied in rye chromosome number and degree of resistance expressed. One line, Venus with seven pairs of rye chromosomes consistently showed levels of resistance intermediate between wheat and rye. A trend was observed where increasing rye chromosome content led to greater resistance but exceptions showed that variation within triticales could not be ascribed to rye chromosome content alone.     

Reaction of tritordeum to Fusarium culmorum and Septoria nodorum

Summary Hordeum chilense is a wild barley extensively used in wide crosses in the Triticeae. It could be a valuable source of resistance to Fusarium culmorum and Septoria nodorum. Some H. chilense x Triticum spp. amphiploids, named tritordeums, were more resistant than the parental wheat line to these diseases, others were not. Average contents of ergosterol and deoxynivalenol (DON) suggested that resistance to colonization by Fusarium was the highest for Hordeum chilense, followed by tritordeum and wheat in decreasing order. In particular, the H. chilense genotypes H7 and H17 enhanced the wheat resistance to F. culmorum in its tritordeum offsprings. Resistance to S. nodorum in tritordeum was not associated with tall plant height. There is sufficient genetic variation for resistance to F. culmorum and S. nodorum among tritordeum to allow the breeding of lines combining short straw and resistance to both diseases.