合浦绒螯蟹的繁殖生物学

为保护和开发合浦绒螯蟹资源,通过生态调查和实验,研究了该蟹的繁殖生物学,结果表明：１、该蟹在浅水中生长,在盐度为８－２５的海水中繁殖;２其生活史包括卵,蚤状幼体,大眼幼体、幼蟹、成蟹几个阶段;３、繁殖季节为１０月到翌年３月,卵和幼体生长发育的适宜水温为１５－２５℃。     

合浦绒螯蟹生长和生态特性

为保护和开发合浦绒螯蟹资源,通过生态调查和养殖试验,研究了该蟹的生长和生态特征,结果表明该蟹在淡水中生长,在盐度8～25的海水中繁殖;其生活史包括卵、蚤状幼体、大眼幼体、幼蟹和成蟹5个阶段.各阶段的生长和生态特征各不相同.规格较大的蟹其绝对生长值也大,但相对生长率则较小;相反,规格较小的蟹其绝对生长值较小,但相对生长率则较大.合浦绒螯蟹交配的适宜水温是1 5～20℃,盐度8～25;蚤状幼体生长的适宜水温为20～25℃,盐度8～25;大眼幼体已趋于淡水生活,其生长适温18～28℃;幼蟹和成蟹在淡水中生活,适温是20～30℃.资源调查和养殖试验结果表明合浦绒螯蟹的生长速度较快,一年内可长成,开展人工养殖是可行的.     

合浦绒螯蟹生长和生态特性

为保护和开发合浦绒螯蟹资源，通过生态调查和养殖试验，研究了该蟹的生长和生态特征，结果表明：该蟹在淡水中生长，在盐度8－25的海水中繁殖；其生活史包括卵、蚤状幼体、大眼幼体、幼蟹和成蟹5个阶段。各阶段的生长和生态特征各不相同。规格较大的蟹其绝对生长值也大，但相对生长率则较小；相反，规格较小的蟹其绝对生长值较小，但 相对生长率则较大。合浦绒螯蟹交配的适宜水温是15－20℃，盐度8－25；蚤状幼体生长的适宜水温为20－25℃，盐度8－25；大眼幼体已趋于淡水生活，其生长的生长速度较快，一年内可长成，开展人工养殖是可行的。     

锯缘青蟹繁殖生物学的研究

为解决锯缘青蟹的种苗生产问题 ,较系统地研究了其繁殖生物学的有关问题。结果表明 ,锯缘青蟹的繁殖季节是 3～ 1 0月 ,体重 1 3 0g以上的青蟹均有交配、生殖能力 ,雌雄比例近 1∶1 ,采用促熟措施可达到雌蟹早产卵的目的 ;适宜胚胎发育水温是 2 0～ 3 0℃ ,当水温 2 5～ 3 0℃时 ,幼体发育随水温增高而加快。并描述了幼体各期的主要特征     

中华绒螯蟹幼体及成蟹的消化酶活性研究

中华绒螯蟹是我国水产养殖上的主要养殖品种之一 ,但其苗种供应和成蟹产量仍不稳定 ,特别是大规格成蟹产量非常低 ,这成为河蟹养殖的一个制约因素。对河蟹消化酶的研究 ,有助于揭示河蟹在各个养殖阶段和环境下的营养需求特点。关于蟹类消化酶的研究 ,仅在幼体方面有些报道 ,如Hirche和 Anger测定了蛛形蛤蟆蟹各期幼体消化酶活力 [1] ;国内学者潘鲁青等研究了中华绒螯蟹幼体的消化酶活性与氨基酸组成[2 ] ;汤鸿等研究了锯缘青蟹幼体消化酶活力。本文测定了中华绒螯蟹幼体及成蟹的消化酶活性 ,试图从消化酶角度探讨中华绒螯蟹的营养需求以及…     

锯缘青蟹蟹奴病的研究

研究发现蟹奴在孵化过程中内层卵先排出,内层囊膜再相继排出,而不是外囊膜先排出。采用烟丝、马尾松、苦楝叶、复合五号药、鸦胆子、使君子等六种药物对蟹奴幼体进行杀灭试验,结果仅烟丝(83.3ppm)和苦楝叶(110ppm)有效,前者5h后杀灭率16.6％,后者24h后杀灭率52.5％。     

锈斑蟳(Charybdis feriatus)室内人工育苗的研究

盐度30、温度27.5～29.5℃、pH7.8～8.6的条件下,投喂扁藻(10×104mL-1)、轮虫(20mL-1～50mL-1)、卤虫无节幼体(1mL-1～30mL-1)及卤虫成体(0.1mL-1),进行锈斑蟳室内人工育苗试验。结果表明:溞状幼体Z1期2～4d,存活率100%;Z2期2～3d,存活率74.0%～78.0%;Z3、Z4、Z5期各3d,存活率分别为37.5%～59.0%、26.5%～43.0%、22.0%～36.7%;Z6期3～5d,存活率19.0%～26.3%;大眼幼体5～6d,存活率11.0%～11.5%;Ⅰ期幼蟹(蟹苗)存活率4.5%～5.0%,整个育苗过程共计20～26d。     

南海海域三疣梭子蟹的幼体培育

幼体期Z1和Z2投喂扁藻和轮虫,Z2后期开始以轮虫和卤虫无节幼体混合投喂,Z3后用卤虫无节幼体投喂,大眼幼体用不同饵料培育,进行南海海域三疣梭子蟹幼体培育,结果表明:溞状幼体平均成活率为15.3%;Z2变态为Z3、Z4变态为M为溞状幼体培育的敏感期,幼体的阶段成活率较低;以卤虫无节幼体、冰冻卤虫成虫、活卤虫成虫为饵料,均能使培育大眼幼体至幼蟹,其中活卤虫成虫投喂、加防残网片培育效果最好,成活率达80%。     

5种波长光对日本沼虾人工育苗幼体成活率的影响

光照与日本沼虾繁殖和孵化关系极为密切。研究了不同波长的光对日本沼虾孵化的影响 ,结果表明 :在环境光谱主峰值 4 70 .5nm、4 77.9nm、4 92 .6nm、5 0 4 .8nm和 6 15 .2nm条件下 ,适度成熟的亲虾都能顺利孵化 ,日本沼虾孵化与否 ,与孵化环境中的光波波长无关 ,而与抱卵日本沼虾胚胎发育有关。日本沼虾在孵化期对不同波长的光谱有明显的视觉敏感度分布 ,在前 4种光谱条件下 ,日本沼虾视觉器官敏感 ,而在光谱主峰值 6 15 .2nm时日本沼虾视觉器官不敏感。这一特点在日本沼虾育苗生产上具指导意义 ,可防止抱卵亲虾在孵化过程中吞食幼体 ,提高幼体成活率     

氮浓度、温度和照度对波吉卵囊藻繁殖模式的影响

【目的】探索波吉卵囊藻(Oocystisborgei)的繁殖模式,调控其生殖过程以实现藻生物质稳定增长。【方法】在荧光显微镜下观察波吉卵囊藻似亲孢子形成过程,探究温度、照度、氮浓度对其繁殖模式的影响。【结果】波吉卵囊藻以2、4和8似亲孢子型模式繁殖,在藻细胞第二轮分裂过程中因分裂不同步,有时也形成3个似亲孢子。氮限制和弱光显著影响波吉卵囊藻繁殖模式(P 0.05)。通常情况下,波吉卵囊藻以4似亲孢子型繁殖模式繁殖,但在缺氮和弱光下2和3似亲孢子型模式的频率上升。在15～35℃温度范围内,波吉卵囊藻繁殖模式变化不大。【结论】波吉卵囊藻有4种繁殖模式。在不良环境中,2和3似亲孢子型模式频率上升。     

Preliminary study on chromosomes of induced triploid in the red sea bream,Pagrosomus major

ＩＮＴＲＯＤＵＣＴＩＯＮＣｈｒｏｍｏｓｏｍｅｍａｎｉｐｕｌａｔｉｏｎｉｓｃｏｎｓｉｄｅｒｅｄｔｏｂｅｖｅｒｙｉｍｐｏｒｔａｎｔｆｏｒｐｒａｃｔｉｃａｌａｐｐｌｉｃａｔｉｏｎｉｎｆｉｓｈｂｒｅｅｄｉｎｇ.Ｔｒｉｐｌｏｉｄｙｈａｓｂｅｅｎｏｆｉｎｔｅｒｅｓｔｂｅｃａｕｓｅｔｒｉｐｌｏｉｄｆｉｓｈａｒｅｓｕｐｐｏｓｅｄｔｏｂｅｓｔｅｒｉｌｅｄｕｅｔｏｔｈｅｆａｉｌｕｒｅｏｆｔｈｅｈｏｍｏｌｏｇｏｕｓｃｈｒｏｍｏｓｏｍｅｓｙｎａｐｓｉｓｄｕｒｉｎｇｅａｒｌｙｇａｍｅｔｏｇｅｎｅｓｉｓ(ＳｕｇａｍａａｎｄＴ…     

某工程静压桩基高应变动力试验与分析

文章介绍了高应变动力试桩的基本原理,并通过高应变动力试桩技术在某静压桩基工程中的应用,分析受挤土效应不利影响下基桩的桩身质量和承载力变化,为处理该类问题提出了一些办法和体会,同时也说明了高应变动力试桩技术解决桩基工程问题的能力.     

Reproductive ecology of the seabob shrimp <Emphasis Type="Italic">Xiphopenaeus kroyeri</Emphasis> (Heller, 1862) in a coastal area of Southern Brazil

The predictability of certain environmental factors that affect the life cycle of the seabob shrimp Xiphopenaeus kroyeri (Heller, 1862) was evaluated in a study of its reproductive biology in an area adjacent to Babitonga Bay, State of Santa Catarina, Brazil. Monthly sampling was conducted from July 2010 through June 2011 at depths of 5, 8, 11, 14, and 17 m. 76 004 individuals were obtained, with a pronounced peak in absolute abundance in austral autumn (34 208), coinciding with the annual closed season from March to May. Grain size composition of the sediment showed the closest relationship to the distribution of individuals (multiple linear regression, P <0.05), related to their burying habit. The observed correlations between the abundance of reproductive males (bearing spermatophores) and females with spent gonads (cross-correlation, P <0.05), and between reproductive males and reproductive females (with a 1-month lag) suggest that the peak of reproductive males preceded the peak of female ones. This result agrees with the pattern expected for females, which copulate in post-ecdysis (spent gonads). Spawning seemed to take place at greater depths, as evidenced by the concentration of reproductive females in these areas. The reproductive activities observed here confirm that this species follows a tropical/subtropical reproductive pattern, spawning continuously throughout the year, with the highest peaks in spring and autumn. The data indicate that the juvenile recruitment period observed in August-September resulted from the reproductive output noted in April–May. Additionally, the reproductive period recorded in November led to the juvenile peak observed in March–May.     

<Emphasis Type="Italic">Grateloupia ramosa</Emphasis> Wang &amp; Luan sp. nov. (Halymeniaceae,Rhodophyta), a new species from China based on morphological evidence and comparative <Emphasis Type="Italic">rbc</Emphasis>L sequences

Grateloupia ramosa Wang & Luan sp. nov. (Halymeniaceae, Rhodophyta) is newly described from Hainan Province, southern China. The organism has the following morphological features: (1) purplish red, cartilaginous and lubricous thalli 5–10 cm in height; (2) compressed percurrent axes bearing abundant branches with opposite arrangement; (3) claw-like apices on top, constricted to 2–4 cm at the base; (4) cortex consisting of 3–6 layers of elliptical or anomalous cells and a medulla covered by compact medullary filaments; (5) reproductive structures distributed throughout the thallus, especially centralized at the bottom of the end portion of the branches; and (6) 4-celled Carpogonial branches and 3-celled auxiliary-cell branches, both of the Grateloupia-type. The morphological diff erences were supported by molecular phylogenetics based on ribulose-1, 5-bisphosphate carboxylase/oxygenase (rbcL) gene sequence analysis. There was only a 1 bp divergence between specimens collected from Wenchang and Lingshui of Hainan province. The new species was embedded in the large Grateloupia clade of the Halymeniaceae. The pairwise distances between G. ramosa and other species within Grateloupia ranged from 26 to 105 bp, within pairwise distances of 13–111 bp between species of the large genus Grateloupia in Halymeniaceae. Thus, we propose this new species as G. ramosa Wang & Luan sp. nov.     

Alkaloids from an algicolous strain of <Emphasis Type="Italic">Talaromyces</Emphasis> sp.

Compounds isolated and identified in a culture of the alga-endophytic fungus Talaromyces sp. cf-16 included two naturally occurring alkaloids, 2-[(S)-hydroxy(phenyl)methyl]-3-methylquinazolin-4(3H)-one (1a) and 2-[(R)-hydroxy(phenyl)methyl]-3-methylquinazolin-4(3H)-one (1b), that were identified for the first time. In addition, seven known compounds (2–8) were obtained from the culture. Following chiral column chromatography, compounds 1a and 1b were identified as enantiomers by spectroscopic analyses and quantum chemical calculations. Bioassay results showed that 5 was more toxic to brine shrimp than the other compounds, and that 3–6 could inhibit Staphylococcus aureus.     

Interspecific competition and allelopathic interaction between <Emphasis Type="Italic">Karenia mikimotoi</Emphasis> and <Emphasis Type="Italic">Dunaliella salina</Emphasis> in laboratory culture

Algal allelopathy is a manifold ecological/physiological phenomenon that is focused on chemical interactions and autotoxicity. We investigated the allelopathic interactions between Karenia mikimotoi and Dunaliella salina in laboratory cultures based on diff erent temperature (15°C, 20°C, and 25°C) and lighting (40, 80, and 160 μmol/(m²·s)) conditions. The growth of D. salina in bi-algae culture (1:1 size/density) was significantly restrained. The results of cell-free filtrate culture indicate that direct cell-tocell contact was not necessary in interspecific competition. Further experimental results demonstrated that allelochemicals released from K. mikimotoi were markedly influenced by both temperature (P =0.013) and irradiance (P =0.003), resulting in diff erent growth characteristics of D. salina in filtrate mediums. Compared with the plateau period, K. mikimotoi exudates in the exponential phase had a stronger short-term inhibition effect on D. salina in normal conditions. A clear concentration-dependent relationship was observed in the effect of allelochemicals released from K. mikimotoi with low-promoting and high-repressing effects on D. Salina in a short time-scale. In addition, allelopathic substances remain stable and effective under high temperature and pressure stress. Many flocculent sediments adhering with D. salina cells were observed in all filtrate mediums, while the quantity and color depended on the original culture conditions.     

Genome size of <Emphasis Type="Italic">Alexandrium catenella</Emphasis> and <Emphasis Type="Italic">Gracilariopsis lemaneiformis</Emphasis> estimated by flow cytometry

Flow cytometry(FCM) technique has been widely applied to estimating the genome size of various higher plants. However, there is few report about its application in algae. In this study, an optimized procedure of FCM was exploited to estimate the genome size of two eukaryotic algae. For analyzing Alexandrium catenella, an important red tide species, the whole cell instead of isolated nucleus was studied, and chicken erythrocytes were used as an internal reference. The genome size of A. catenella was estimated to be 56.48 ± 4.14 Gb(1C), approximately nineteen times larger than that of human genome. For analyzing Gracilariopsis lemaneiformis, an important economical red alga, the purified nucleus was employed, and Arabidopsis thaliana and Chondrus crispus were used as internal references, respectively. The genome size of Gp. lemaneiformis was 97.35 ± 2.58 Mb(1C) and 112.73 ± 14.00 Mb(1C), respectively, depending on the different internal references. The results of this research will promote the related studies on the genomics and evolution of these two species.     

Equality testing for soil grid unit resolutions to polygon unit scales with DNDC modeling of regional SOC pools

Matching soil grid unit resolutions with polygon unit map scales is important to minimize the uncertainty of regional soil organic carbon(SOC) pool simulation due to their strong influences on the modeling.A series of soil grid units at varying cell sizes was derived from soil polygon units at six map scales,namely,1:50 000(C5),1:200 000(D2),1:500 000(P5),1:1 000 000(N1),1:4 000 000(N4) and 1:14 000 000(N14),in the Taihu Region of China.Both soil unit formats were used for regional SOC pool simulation with a De Nitrification-DeC omposition(DNDC) process-based model,which spans the time period from 1982 to 2000 at the six map scales.Four indices,namely,soil type number(STN),area(AREA),average SOC density(ASOCD) and total SOC stocks(SOCS) of surface paddy soils that were simulated by the DNDC,were distinguished from all these soil polygon and grid units.Subjecting to the four index values(IV) from the parent polygon units,the variations in an index value(VIV,%) from the grid units were used to assess its dataset accuracy and redundancy,which reflects the uncertainty in the simulation of SOC pools.Optimal soil grid unit resolutions were generated and suggested for the DNDC simulation of regional SOC pools,matching their respective soil polygon unit map scales.With these optimal raster resolutions,the soil grid units datasets can have the same accuracy as their parent polygon units datasets without any redundancy,when VIV 1% was assumed to be a criterion for all four indices.A quadratic curve regression model,namely,y = – 0.80 × 10~(–6)x~2 + 0.0228 x + 0.0211(R~2 = 0.9994,P 0.05),and a power function model R? = 10.394?~(0.2153)(R~2 = 0.9759,P 0.05) were revealed,which describe the relationship between the optimal soil grid unit resolution(y,km) and soil polygon unit map scale(1:10 000x),the ratio(R?,%) of the optimal soil grid size to average polygon patch size(?,km~2) and the ?,with the highest R~2 among different mathematical regressions,respectively.This knowledge may facilitate the grid partitioning of regions during the investigation and simulation of SOC pool dynamics at a certain map scale,and be referenced to other landscape polygon patches' mesh partition.     

Phenylquinolinones with antitumor activity from the Indian Ocean-derived fungus <Emphasis Type="Italic">Aspergillus versicolor</Emphasis> Y31-2

Two phenylquinolinones, including one new compound (1) and a previously isolated compound (2), were isolated from the ethyl acetate extracts of the fungus Aspergillus versicolor Y31-2, which was obtained from seawater samples collected from the Indian Ocean. The structures of these compounds were established by spectroscopic analyses. 4-(3-Hydroxyphenyl)-3-methoxyquinolin-2(1H)-one (1) exhibited moderate cytotoxicity against MCF-7 (human breast carcinoma cell line) and SMMC-7721 (human liver cancer cell line) cells with IC₅₀ values of 16.6 and 18.2 μmol/L, respectively. To the best of our knowledge, this study represents the first reported account of the isolation of compounds 1 and 2 as the secondary metabolites of the seawater derived fungus Aspergillus versicolor from the Indian Ocean.     

Unusual hydrocarbon waxes detected in <Emphasis Type="Italic">Salix oritrepha</Emphasis> leaf from Nianbaoyeze Mountains,eastern Qinghai-Tibetan Plateau

Plant biomarkers, such as hydrocarbon waxes, are frequently found in various sediments and could be adopted as paleovegetation and paleoclimate indicators. Nevertheless, scarce researches have focused on leaf waxes in higher plants of alpine region. Herein, hydrocarbon leaf wax components of Salix oritrepha, which flourish in Nianbaoyeze Mountains in eastern Tibetan Plateau were fully discussed. The n-alkane distribution in leaves ranges from n-C₂₁ to n-C₂₉ with maxima at n-C₂₅, which were entirely different with Salix taxa displayed in previous surveys in non-alpine regions. The unusual even carbon nalkenes from n-C_22:1 to n-C_30:1, which were thought to appear only in aquatic organisms, were firstly reported in an alpine plant. Additionally, iso-(2-methyl) alkanes, ranging from i-C₂₃ to i-C₂₉ with maxima at i-C₂₅, which have been commonly reported in microorganisms, were also identified in an alpine plant for the first time. Unusual hydrocarbon distribution detected in Salix oritrepha leaf from Nianbaoyeze Mountains is most likely due to the extreme environment in such alpine region.