The harvest of the freshwater crayfish <Emphasis Type="Italic">Astacus leptodactylus</Emphasis> Eschscholtz in Turkey: harvest history,impact of crayfish plague,and present distribution of harvested populations

This review focuses on the present distribution of populations of the crayfish Astacus leptodactylus that are harvested in Turkey. It also examines the history of this harvest and the impact that crayfish plague has had on them. Crayfish plague, caused by the fungus-like organism, Aphanomyces astaci Schikora, 1906, is a severe parasite of freshwater crayfish and has caused a lot of damage to A. leptodactylus populations in Turkey since 1984. Turkey was the largest provider of A. leptodactylus to Western Europe from 1970 (or possibly earlier) until 1986. For example, the peak production was reached in the early 1980s, with over 5,000 tonnes being exported in 1984. On the other hand, as a result of the crayfish plague the harvest of A. leptodactylus was reduced severely in most populations in Turkey after 1985. The harvest was only 320 tonnes in 1991. After the occurrence of crayfish plague in Turkey, in order to increase crayfish production uncontrolled A. leptodactylus stockings have been carried out in many waterbodies throughout Turkey. These introductions have caused an increase in the number of A. leptodactylus populations, but exploitation of A. leptodactylus is still under the pressure of the plague, although there has been a steady increase in crayfish production in recent years. The harvest increased to 2,317 tonnes in 2004. Fortunately, among those populations affected by crayfish plague, large amounts of A. leptodactylus can still be harvested from three lakes, ?znik (Bursa), E?irdir (Isparta) and Çivril (Denizli). Thus, it seems that A. leptodactylus has a degree of resistance to crayfish plague. It is therefore interesting to investigate the resistance of A. leptodactylus caught from these populations to crayfish plague.     

Transpositional feeding rhythm of loach <Emphasis Type="Italic">Misgurnus anguillicaudatus</Emphasis> from larvae to juveniles and its ontogenesis under artificial rearing conditions

The diel feeding rhythm and ontogenesis during early life stage of loach Misgurnus anguillicaudatus were investigated under experimental conditions (light: L 06:00–18:00, D 18:00–06:00 h). Morphological and behavioral developments of loach from newly hatched to 40 days after hatching were observed. Larvae were able to prey on daphnia 3–4 days after hatching at 23 ± 0.5°C. As the larvae grew, they showed an increasing feeding capacity and a distinct feeding rhythm. Feeding intensity and incidence for day-4 larvae were highest at 10:00 and 16:00 h. The highest levels of feeding intensity for day-12 larvae occurred at 08:00, 12:00, and 18:00 h as did feeding incidence. By day 20, when the larvae metamorphosed, the highest levels of feeding intensity occurred at 06:00, 18:00, and 24:00 h and were concurrent with the highest feeding incidence. After metamorphosis, feeding capacity had again increased considerably and, in contrast to the earlier stages before day 20, feeding intensity for day-30 juveniles peaked at 05:00 and 20:00 h, about 1–2 h after the maximum feeding incidence. The feeding rhythm of loach juveniles at day 40 was almost the same as the day-30 juveniles. The estimated maximum daily feeding rates were 43.1%, 33.4%, 19.0%, 12.8%, and 5.8% of body weight on days 4, 12, 20, 30, and 40, respectively. Thus, loach was found to have different feeding rhythms in the pre- and post-metamorphosis stages, with the highest feeding activity in daytime during the larval planktonic stage before metamorphosis, and intensely nocturnal feeding behavior during the juvenile benthic stage after metamorphosis.     

浅析林场木材生产成本超支原因及应采取的措施

本文就林场生产的高投入,低产出,忽视资源配置与效益的关系以及实行机畜结合,克服林区生产领域生产成本超支的通病提出了切实可行的方法。     

火山岩和沸石填料BAF深度处理印染废水的效能比较

针对纺织印染行业水质不达标回用率低的问题,采用火山岩和沸石为填料的曝气生物滤池对纺织印染废水二级生化出水进行了深度处理,进行了两反应器出水效能的比较。研究表明:火山岩填料深度处理纺织印染废水的效能要高于沸石填料,建议气水比在10∶1左右,出水CODcr为36~48mg/L,出水色度35~55度,NH3-N浓度0.5~1.7mg/L,出水浊度范围0.9~3NTU。     

整枝方式对不同株型棉花品种产量及纤维品质的影响

采用两个株型存在明显差异的棉花品种鲁棉研37号和德棉16号,设置三种不同整枝方式(不整枝、简化整枝、精细整枝),研究了不同整枝方式对不同株型棉花品种产量及纤维品质的影响。结果表明:在种植密度为5.25万株/hm^2条件下,鲁棉研37号株高显著高于德棉16号,整枝方式对株高和果枝数影响不显著;鲁棉研37号简化整枝处理籽棉产量和皮棉产量均最高,且籽棉产量显著高于精细整枝处理,德棉16号在不整枝处理下籽棉产量和皮棉产量最高,与精细整枝处理无显著差异,但显著高于简化整枝处理;不同整枝方式对两个品种纤维上半部平均长度和整齐度指数存在一定影响,但纤维指标均能达标。由此可见,在该密度条件下,株型紧凑型品种鲁棉研37号更适合简化整枝处理,松散型品种德棉16号更适合不整枝处理。     

苎麻新品种“华苎4号”选育研究

“华苎 4号”是从稀节巴品种自然杂交后代中选育出来的新品种。该品种产量高 ,在品系比较试验中平均亩产 2 2 6 .5kg ,比对照细叶绿品种增产 5 9.1 3% ,在湖北省区试中较对照增产 33.81 % :纤维品质优良 ,在品系比较试验中年均纤维细度 2 0 82支 ,在区试中经湖北省纤检所测试 ,年均纤维细度 2 2 39支 ;该品种植株高大整齐 ,出麻率特别高 (鲜皮出麻率和鲜茎出麻率分别在 1 4%和 5 %以上 ) ;“华苎 4号”的抗逆性强 ,高抗炭疽病 ,不感染花叶病 ,抗旱抗风性强 ,但耐渍性略差。     

热带海岸次生林群落主要乔木的种间关联分析

对热带海岸次生林群落主要乔木种群的重要值、方差比率、χ~2统计量和Ochiai(OI)指数等种间联结性指标进行测定,旨在揭示该群落优势种群之间相互作用的内在关联及种对间关联性的内在规律。结果表明:香蒲桃是热带海岸次生林群落的主要建群种;热带海岸次生林群落19个主要种群总体关联性表现为不显著正关联,反映了该群落尚未达到稳定的演替阶段;χ~2检验结果显示该群落优势种群正关联种对与负关联种对数量相当,无关联种对数较少,分别占总对数的42.7%、43.3%和14.0%,显著正关联种对数为1对,极显著和显著负关联种对数为2对;Ochiai(OI)指数显示66对种对的OI值落在[0.6,1],反映出热带海岸次生林主要种对间关联程度较为紧密。综上所述,热带海岸次生林群落优势种群种对间种间关联明显,物种之间存在一定的独立性,整体趋向稳定发展,实践中为加快热带次生林演替的进程,应重点保护正联结性较强的树种。     

甘蔗脱毒种苗旱地新植试验总结

根据本试验新植的调查分析表明:新台糖22号、新台糖25号和粤糖93-159甘蔗种苗脱毒后产量和糖分大幅提高,新台糖25号增产23.8％,增糖0.5％(绝对值);新台糖22号增产14.0％,增糖0.7％(绝对值);粤糖93-159增产8.5％,增糖0.5％(绝对值).产量和糖分增加不明显的是粤糖86-368增产14.1％,盈育91-59增产7.2％.粤糖82-882、粤糖83-88、粤糖00-236产量和糖分都无明显变化.     

大豆品种的抗病性与叶片内苯丙氨酸解氨酶活性关系的研究

在抗病品种东农9674，东农1572和感病品种黑农39，东农95-165上接种大豆灰斑病菌的1号，2号，4号，6号，7号等5个生理小种，测定从接种到显症前与抗性有关的苯丙氨酸解氨酶活性的变化。研究结果表明，抗病的大豆品种接种不同生理小种的灰斑病菌后，PAL的活性分别从第6-7天起吴上升趋势且明显高于对照；相反感病品种从8-9天起PAL活性明显低于对照，因此说明PAL的活性与大豆抗灰斑病性呈正相关关系。     

大豆贮藏蛋白基因及其表达调控研究进展

简要介绍了大豆的两类主要贮藏蛋白大豆球蛋白和β—伴大豆球蛋白基因的组织、结构和表达调控的研究进展。编码大豆球蛋白5种亚基的基因均已被克隆，Gy1和Gy2紧密连锁，Gy3、Gy4和Gy5分别位于不同染色体上，每个基因都包含四个外显子和三个内含子，其外显子的同源性很高，其调控序列也具较强的保守性。β—伴大豆球蛋白的基因为至少15个成员的大家族，至少分布在两条染色体上，主要集β—于三个区域，它们之间的同源性很高，但各亚基都有其独特的表达调控方式。