• Volume 42,Issue 12,2018 Table of Contents
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    • Inhibitory effect of four antibiotics on Chroococcus turgidus co-cultured tothe filaments of Scytosiphon lomentaria

      2018, 42(12):1906-1915. DOI: 10.11964/jfc.20170910975

      Abstract (1398) HTML (606) PDF 1.25 M (1259) Comment (0) Favorites

      Abstract:In order to suppress the growth of Chroococcus turgidus and finally eliminate it during the amplification process of filaments of Scytosiphon lomentaria, the effects of four antibiotics:cefotaxime sodium (CTX), amoxicillin (AM), tetracycline (TC) and erythromycin (EM) on the growth of filaments of S. lomentaria and C. turgidus, which were co-cultured in the research, were studied by experimental ecology methods in this paper. Results indicated that CTX can inhibit the growth of C. turgidus significantly at the concentration of 50 and 100 mg/L. On the 20th day, their average daily growth rates were 3.84% and -0.96%, respectively, which were significantly lower than 19.21% in the control group without antibiotics, therefore ensuring the normal growth and development of filaments of S. lomentaria. Both C. turgidus and the filaments of S. lomentaria were not suppressed by AM at the concentrations between 50 and 1 000 mg/L, so AM can not eliminate C. turgidus in the co-culture system. TC could inhibit the growth of C. turgidus and the filaments of S. lomentaria dramatically at the concentration of 100 and 200 mg/L, but the cytoplasm of filaments of S. lomentaria presented atrophy. EM inhibited the growth of C. turgidus significantly at the concentrations between 0.10 mg/L and 1.00 mg/L, when the concentration was higher than 0.50 mg/L, the growth of filaments of S. lomentaria also were inhibited, even to death.

    • Relationship between Cololabis saira fishery distribution patterns and sea surface temperature front in the Northwestern Pacific Ocean

      2018, 42(12):1916-1926. DOI: 10.11964/jfc.20180211189

      Abstract (1533) HTML (571) PDF 1.35 M (1360) Comment (0) Favorites

      Abstract:Pacific saury (Cololabis saira) fishery in North Pacific Ocean (NPO) is one of the most important components for Chinese fishery industry. The distribution of fishery is significantly related to the sea surface temperature (SST) and its variations. In this study, the sea surface temperature gradient (SSTG) and temperature fronts are derived from SST remote sensing data. In addition, data from Chinese saury fishery in the NPO during 2013 to 2015 (not including the fishery data of Chinese Taipei) are used to analyze the spatial and temporal relationship between the temperature front and the saury abundance. The results show that the main Saury fishing grounds are mainly located in 37°-49°N, 145°-165°E. The catch per unit effort (CPUE) is negatively related to the SST in the range of 10-14℃. In contrast, CPUE increases with the sea surface temperature in the range 14-17℃. The most suitable temperature is between 12.5-14.5℃. The CPUE is significantly linear positively correlated with SSTG in the range of 0.01-0.06℃/km, then the best range of SSTG is 0.01-0.05℃/km. Furthermore, the locations of fronts of the study area are also positively correlated with CPUE with the high correlation coefficient of 0.81. The distance (DIST) between CPUE and front shows seasonal variations. During Jun-Aug, when DIST less than 100 km, CPUE displays a positive relationship to DIST with R2 of 0.85. CPUE negatively correlates with DIST and the R2 is 0.9 during Sep-Nov, when the 90% fishing grounds are concentrated within the area, the DIST is less than 50 km. Results show that the SST significantly affects the migratory distributions of saury fishery. Cold water wedges and temperature fronts are concentrated near the intersection of Kuroshio and Oyashio, where the group of saury is clustered to form a high-yield fishing ground.

    • Effect of taurine supplemention at different dietary lipid levels on growth performance, body composition, hepatopancreas biochemical index and antioxidant capacity of juvenile common carp (Cyprinus carpio)

      2018, 42(12):1927-1939. DOI: 10.11964/jfc.20170910961

      Abstract (1389) HTML (567) PDF 614.25 K (1479) Comment (0) Favorites

      Abstract:This experiment was aimed to investigate the effects of taurine supplemention at different dietary lipid levels on growth performance, body composition,hepatopancreas biochemical index and antioxidant capacity of juvenile Cyprinus carpio. A total of 720 healthy juvenile C. carpio with average initial body weight of (1.17±0.01) g were randomly divided into eight treatments (3 replicates per treatment and 30 carp each replicate).Eight isonitrogenous and isoenergetic experimental diets were formulated with the graded taurine levels (0,400, 800 and 1 600 mg/kg dry diet, respectively) in dietary lipid level of 4.65% and 10.22% respectively. The experiment lasted for 56 days. The results showed that the weight gain ratio (WGR), the specific growth ratio (SGR) and protein efficiency ratio (PER) of juvenile C. carpio in 4.65% lipid group were higher than 10.22% lipid group, at the same time, the feed conversion ratio (FCR) was the lower than 10.22% lipid group when taurine were not added. The WGR、SGR、PER were significantly improved, while the FCR were significantly decreased when taurine were added. The WGR、SGR、PER of juvenile C. carpio initially increased with increasing dietary taurine levels and then towards stability. Conversely, the feed conversation ratio (FCR) first decreased and then towards stability. The WGR, SGR, PER were all the highest when the dietary taurine level was 800 mg/kg, at the same time, the FCR was the lowest. The WGR、SGR、PER were significantly higher and the FCR were significantly lower in the 10.22% lipid group than 4.65% lipid group when taurine was added more than 800 mg/kg. The total cholesterol (TCH) and triglyeride (TG) in hepatopancreas were gradually decreasing with taurine level increasing. However, there was no significant difference in the 4.65% lipid group, while the difference in the 10.22% lipid group was significant, and the condition factor (CF) of juvenile C. carpio first increased with increasing dietary taurine levels and then towards stability, at the same time, the hepatosomatic index (HIS) and viscerosomatic index (VSI) first decreased and then lowards stability. The crude protein in whole body first increased with increasing dietary taurine levels and then owards stability,while the crude lipid first decreased and then towards stability. With the increase of dietary taurine level, the activities of superoxide dismutase (SOD), catalase (CAT) in hepatopancreas first increased then decreased, the activities of SOD and CAT were all the highest when the dietary taurine level was 800 mg/kg. At the same time, the content of malondialdehyde (MDA) in hepatopancreas was gradually decreasing, and the the content of MDA was the lowest when the dietary taurine level was 1 600 mg/kg. Results of above show that the appropriate dietary taurine level (800-1 600 mg/kg) could effectively improve the utilization of dietary lipid, promote the growth, reduce the lipid deposition, improve the muscle quality and the antioxidant capacity of C. carpio.

    • Effects of dietary lipid levels on growth, body composition, digestive enzyme activities, serum biochemical indexes and antioxidant performance of Polyodon spathula

      2018, 42(12):1940-1956. DOI: 10.11964/jfc.20180111138

      Abstract (1403) HTML (677) PDF 887.70 K (1309) Comment (0) Favorites

      Abstract:This study investigated the effects of dietary lipid levels on growth performance, body composition, digestive enzyme activities, serum biochemical indexes and antioxidant enzyme activities of paddlefish (Polyodon spathula). A total of 270 P.spathula with initial body weight of (81.38±0.14) g were randomly divided into five groups with 3 replicates per group and fed with five diets (dietary protein level 41.35%) containing different lipid levels (3.01%, 5.12%, 7.14%, 9.35% and 11.64%) for 8 weeks. With the increment of dietary lipid level, weight gain rate, specific growth rate, feed conversion ratio, protein efficiency ratio, hepatosomatic index and condition factor of P.spathula all showed a trend of first rising and then decreasing, and regression analysis determined that the specific growth rate and protein efficiency ratio reached the maximum when the dietary lipid level was 7.88% and 9.47%, respectively. The lipid content of muscle and liver increased with the increase of dietary lipid level, and the lipid content in 11.64% group was significantly higher than those in 3.01%, 5.12% and 7.14% groups. The total fish and muscle crude protein contents were related to dietary lipid level, and crude protein contents in total fish and muscle of 3.01% groups were the lowest, while 7.14% and 9.35% groups had no significant difference. Main fatty acid composition in the muscle and liver of the P.spathula were related to the fatty acid in the feed, with the increase of dietary lipid level, the ratio of n-6PUFA in the muscle and liver increased, the n-3/n-6 PUFA and SFA (C16:0, C18:0) in the liver decreased; MUFA C18:1n-9 first ascended, then decreased, and there was no significant difference in the proportion of n-3HUFA and n-3PUFA in the fatty acid composition of muscle and liver. The enteric protease activity of 7.14% group was significant higher than 9.35% group, α-amylase activity was more stable when lipid level reached 7.14%, and no significant difference between hepatic protease and lipase activity. The concentration of serum total protein, albumin and globulin increased with the increase of lipid level, the serum total cholesterol and high density cholesterol concentration in 11.64% group were significantly higher than 3.01% group, in addition, alanine aminotransferase and aspartate aminotransferase were not affected by dietary lipid level. The serum superoxide dismutase activity reached the maximum when dietary lipid level was 9.69%, and there was no significant difference in glutathione peroxidase activity and malondialdehyde content. The superoxide dismutase activity of liver in 11.64% group was significantly lower than other groups and glutathione peroxidase activity in 9.35% group was significantly higher than other groups except 11.64% group, whereas there was no significant difference in glutathione and malondialdehyde content. The comprehensive analysis of growth, feed utilization, fish quality, digestive enzyme activity and healthy condition showed that appropriate lipid level for P.spathula was 7.88%-9.69% under this trial condition.

    • Clone and relative expression of Os-IP3R and Os-RyR to discuss the evolutionary relationship in Onchidiidae

      2018, 42(12):1857-1868. DOI: 10.11964/jfc.20170610881

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      Abstract:In this study, full-length cDNA of Os-IP3R and Os-RyR in Onchidium struma was cloned by transcriptome data mining and rapid amplification cDNA ends (RACE) methods, and we analyzed the relationship between the percentages of Os-IP3R/Os-RyR expression and the evolution of 3 species from family Onchidiidae. The bioinformatic analysis and expression pattern of Os-IP3R and Os-RyR in different tissues from Onchidium struma, Platevindex mortoni and Peronia verruculata detected by Real-time quantitative PCR were performed. The results show that length cDNA of Os-IP3R consists of 4 574 base pairs (bp), and 2 808 bp open reading frame (ORF) which encodes 935 amino acids. The predicted moleculer of the deduced amino acid of IP3R has six transmembrane domains. The length cDNA of Os-RyR consists of 1 253 base pairs (bp), and 1 131 bp open reading frame (ORF) which encodes 376 amino acids. The predicted molecular of the deduced amino acid of RyR has three transmembrane domains. The IP3R and RyR amino acid sequences in O. struma were aligned and found to be highly conserved in the G*R*GGG*GD at region of calcium channel. Os-IP3R and Os-RyR were detected by qRT-PCR in different tissues of three kinds of Onchidiidae, and the percentages of Os-IP3R/Os-RyR expression from three species were consistent with their living environment (from high tide zone to shallow sea), followed by O. struma, P. mortoni and P. verruculata. The species of higher terrestrial ability with higher percentages of Os-IP3R/Os-RyR gene expression, illustrated percentage of gene expression associated with evolutionary degree. According to the comparison of percentage in Onchidiidae, we hope to provide a valuable clue for amphibian investigators, and to give a molecular biology clue for studying sea to land transition of marine invertebrate.

    • Cloning of HMGB1 gene from Schizothorax prenanti and its response to Aeromonas hydrophila stress

      2018, 42(12):1957-1966. DOI: 10.11964/jfc.20180411240

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      Abstract:In order to understand the immune response of Schizothorax prenanti high mobility group box 1 (SpHMGB1) to Aeromonas hydrophila stress, primers were designed by the sequence obtained from the TSA database of spleen in S. prenanti, then the sequence characterization was analyzed. Finally the response situations were detected by qPCR after A.hydrophila infection in vivo and heat-killed A.hydrophila stimuli in vitro. Sequence analysis results showed that the open reading frame of SpHMGB1 was 615 bp which encoded a peptide of 204 amino acids with a predicted molecular mass of 23.5 Ku and a theoretical isoelectric point of 6.79. The peptide contained two basic HMG boxes:box A and box B, and an acidic tail. The secondary structure was mainly composed of 47.06% of α-helices and 50% of random curls. Phylogenetic tree showed that SpHMGB1 and HMGB1 from Danio rerio and Carassius auratus were clustered together among fish HMGB1 with the high identities of 90.7% and 90.4%, respectively. After A.hydrophila infection, the relative expression of SpHMGB1 was significantly up-regulated at different time in tissues. The highest relative expression of SpHMGB1 appeared in kidney at 6 h, in blood at 72 h and in spleen at 120 h. After heat-killed A. hydrophila stimuli in macrophages, the relative expression of SpHMGB1 was down-regulated within 0.5 -24 h with the lowest at 24 h. Meanwhile the relative expression of IL-1β and TNF-α showed the up-regulated tendency. qPCR results suggested that SpHMGB1 might be involved in the immune response after A. hydrophila infection in S. prenanti. This study provided a theoretical basis for further revealing the immune-modulatory mechanism of SpHMGB1 in bacterial disease of cold-water S. prenanti.

    • Analysis of the characteristics of Litopenaeus vannamei intestinal microflora after being fed with two probiotics using high-throughput sequencing method

      2018, 42(12):1967-1976. DOI: 10.11964/jfc.20180211184

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      Abstract:In order to analyze the effect of Rhodobacter capsulatus and Bacillus cereusr on the intestinal microorganism of Litopenaeus vannamei, the experiment was carried out for 30 days in order to study the effect of two probiotics on the culture and feeding of L. vannamei. The 16s rDNA V4 region of intestinal microorganism of L. vannamei was sequenced with high throughput in the later stage of feeding to analyze the structural characteristics of intestinal microflora of L. vannamei fed with different probiotics, and combined with the macroscopical indexes of the growth rate of body mass and the cumulative mortality of the prawn after poisoning. The results:①the range of OTU was 374~506, in which the number of OTU in intestinal tract of the prawn was the lowest in blank group, and the number of OTU in intestinal tract of shrimp was relatively high in two groups after feeding probiotics; ②at the level of phylum classification, the number of Proteobacteria was the highest in three groups, the CK group was mainly Proteobacteria and a small amount of Bacteroidetes, the Bc group was mainly Proteobacteria, Bacteroidetes, Tenericutes, Firmicutes and Gemmatimonadetes, the Rc group was mainly Proteobacteria, Bacteroidetes, Firmicutes, Acidobacteria, Actinobacteria, Fusobacteria and Cyanobacteria; ③the results of rarefaction curve and Shannon index showed that the species abundance and complexity of blank samples were the lowest, and the sample abundance and complexity of B.cereus group were relatively high; ④PCA analysis showed that the microbial composition of the samples of R. capsulatus group and blank group was close. Combined with the results of macroscopical growth rate of shrimp body mass and cumulative mortality after poisoning, it can be seen that the effect of B. cereus on intestinal microflora of L. vannamei is more significant than that of R. capsulatus, and the probiotic effect is better. The results showed that feeding probiotics could augment the abundance of intestinal microflora of L. vannamei, inhibit the growth of harmful bacteria such as Vibrio, increase the growth rate of body mass and reduce the mortality of prawn, so as to achieve the probiotic effect. The effect of feeding B. cereus was better than that of R. capsulatus.

    • 5-HT2AR gene clone and temporal-spatial expression in the mussel Mytilus coruscus

      2018, 42(12):1869-1879. DOI: 10.11964/jfc.20180811409

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      Abstract:To understand the role of serotonin 5-HT2A receptor (5-HT2AR) gene in the growth and development of the mussel Mytilus coruscus, we cloned the 5-HT2AR gene cDNA full length of M. coruscus through RACE technology and analyzed the temporal and spatial expression of this gene via the real-time fluorescent quantitative PCR (qRT-PCR). The full length of 5-HT2AR gene was 2 636 bp and 2 124 bp of open reading frame (ORF) encoding 707 amino acids. Homologous analysis of the amino acids of 5-HT2AR gene in M. coruscus shared high similarity with Homo sapiens (45%), Mus musculus (45%), Danio rerio (48%), Crassostrea gigas (49%) and Mizuhopecten yessoensis (67%), respectively. This study showed that 5-HT2AR mRNA expression was detected in all tissues and the highest expression was found in gill and female gonad, indicating that 5-HT2AR gene may play an important role in perception of the external environment and promotion of mature oocytes. The 5-HT2AR mRNA was expressed at all developmental stages, suggesting that 5-HT2AR gene may be involved in the regulation of the growth and development. Taken together, our findings may provide new insights into clarifying the function of 5-HT gene family in molluscs.

    • Techniques of salted jellyfish dealumination by optimized ultrasonic-assisted methodology

      2018, 42(12):1977-1987. DOI: 10.11964/jfc.20171111022

      Abstract (1329) HTML (572) PDF 1.57 M (1269) Comment (0) Favorites

      Abstract:In order to study the technological conditions of salted jellyfish dealumination by ultrasonic-assisted method, residual aluminum content is detected by ICP-MS through experiment with salted jellyfish as raw material. First, a study is made of the impact of multiple preservative solution concentration, ultrasonic power, ultrasonic frequency and ultrasonic time on the dealumination effect of salted jellyfish by single factor experiment. And then, based on analyzing Box-Behnken central composite design and Response Surface, an optimization is made of multiple preservative solution dealuminating process as well as ultrasonic-assisted dealuminating technology respectively. The experimental results show that the optimizing conditions without ultrasonic assisted treatment go as follows:raw material-to-water ratio is 1:7 (g/mL); soaking time, 4 h; water changing number, 3 times and the jellyfish lowest residual aluminum content (wet base)is 126.4 mg/kg. Thus it can be seen that the soaking time has the most significant effect upon salted jellyfish dealumination; the factors affecting salted jellyfish dealumination by ultrasonic assisted treatment are:ultrasonic time > ultrasonic power > ultrasonic frequency > multiple preservative solution concentration. Among them, the optimum ultrasonic conditions are:ultrasonic frequency is 28 kHz, ultrasonic power 272.61 W, concentration(V[acetic acid]:m[calcium propionate]=1:2), 0.68% and ultrasonic time 35.06 min. Thus, the jellyfish aluminum residue(wet base) can be reduced to 124.46 mg/kg, and the maximum removal rate of aluminum can be up to 85.3%. Actual dealumination obtained from the validation test is 82.1%. Compared with the theoretical prediction values, the relative error rate from the experimental results is 3.2%. This study also indicates that the removal rate of aluminum is stable with hours reduced from 12 to 1.75 and process efficiency improved by 6.9 times. Therefore, application of ultrasonic technology to jellyfish industry will provide theoretical references for highly-efficient development of low aluminum salted jellyfish products.

    • Inter-specific hybridization between Patinopecten yessoensis and P. caurinus

      2018, 42(12):1880-1888. DOI: 10.11964/jfc.20180111120

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      Abstract:In order to solve the problems in the cultivation of the Patinopecten yessoensis, a crossbreeding experiment was carried out between P. yessoensis and P. caurinus. Two hybrids, P. yessoensis(♀)×P. caurinus(♂)(PY♀×PC♂) and P. caurinus(♀)×P. yessoensis(♂)(PC♀×PY♂), together with purebred P. yessoensis and P. caurinus were produced. The PY♀×PC♂ cohort outperformed both pure-bred parental cohorts in both larval and juvenile growth with medial performance in fertilization rate, hatching rate and larval survival rate between two pure-bred cohorts. The PC♀×PY♂ exhibited negative hetereosis in fertilization rate, hatching rate and larval growth, as well as in survival rate. It seems that the origin of eggs had significant influence on performance of hybrids. The results thus suggest that it is possible to improve the stock of the local Japanese scallops by hybridizing them with P. caurinus.

    • Removal of heavy metals from electroplating wastewater by Sargassum fusiforme biomass

      2018, 42(12):1988-1996. DOI: 10.11964/jfc.20171111069

      Abstract (1317) HTML (663) PDF 904.54 K (1127) Comment (0) Favorites

      Abstract:Algal bioadsorbents can effectively remove the single heavy metal ion in aqueous solution, but the removal mechanism of coexisting multiple metal ions was relatively complicated. In this paper, Sargassum fusiforme biomass, pretreated by NaOH, was used to remove heavy metal ions[Cu(Ⅱ), Zn(Ⅱ), Cr(VI) and Ni(Ⅱ)] in the electroplating wastewater, and the effects of pH, temperature, contact time and biomass doses on the removal efficiency and its adsorption mechanism were investigated. The results showed that the optimum pH in the removal efficiency of Cu(Ⅱ), Zn(Ⅱ) and Ni(Ⅱ) was among 6-9, while for Cr(VI), it was 2. The removal efficiency increased when biomass doses were elevated from 2 to 4 g/L, but it maintained constant when the biomass doses were higher than 4 g/L. The adsorption equilibrium of Zn(Ⅱ) and Ni(Ⅱ) was reached at about 25 min while for Cr (VI) and Cu (Ⅱ), it was slightly slow. The influence of temperature on adsorption of heavy metal ions was not obvious. Langmuir model can closely describe the adsorption of heavy metal ions, which indicated the absorption was the monolayer adsorption. The maximum adsorption capacity for Cr (VI) and Ni(Ⅱ) was significantly higher than that for Cu (Ⅱ) and Zn(Ⅱ). The adsorption kinetic can be described by the pseudo-second order kinetic model, indicating that the adsorption process was mainly chemical adsorption. Fourier transform infrared spectroscopy analysis of the adsorbent before and after adsorption showed that the bioabsorption of heavy metals was mainly related to carboxyl group. The results suggested that the algal adsorbent could effectively remove the heavy metal ions in electroplating wastewater and exhibit a good application prospect.

    • Effect of acute ammonia toxicity on genes involved in antioxidant and inflammation in head kidney macrophage of Pelteobagrus fulvidraco

      2018, 42(12):1889-1895. DOI: 10.11964/jfc.20170910969

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      Abstract:A study was carried out to test the response of genes involved in antioxidant and inflammation in head kidney macrophage to acute ammonia toxicity for 96 h. 0.14 and 0.28 mg/L total ammonia nitrogen (TA-N) groups had lower mRNA expression of SOD than that of fish in control, but the highest mRNA expression of GPX was found in 0.28 mg/L TA-N group; 0.14 and 0.28 mg/L TA-N groups had lower mRNA expression of IL-1 and TNF than those of control group, and 0.28 mg/L TA-N group had lower mRNA expression of IL-8 than that of fish in 0.14 mg/L TA-N and control groups; detection with acridine orange staining showed that irregular acridine signal were detected in fish head kidney macrophage cells (HKMC) exposed to 0.14 mg/L TA-N, while HKMC treated with 0.28 mg/L TA-N exhibited extremely high fluoresence intensity. This study indicated that ammonia exerts its toxic effects by interfering with the mRNA expression of antioxidant genes; the apoptosis may be one of the main causes of death caused by ammonia poisoning.

    • Otolith morphology of Saurogobio dabryi and the variance in different sections of Jialing River

      2018, 42(12):1896-1905. DOI: 10.11964/jfc.20180111121

      Abstract (1337) HTML (764) PDF 908.43 K (1265) Comment (0) Favorites

      Abstract:The purposes of this study were to understand the otolith morphology of Saurogobio dabryi in Jialing River, as well as its phenotypic consequences of water environments variations. 195 S. dabryi individuals were collected from the upper (Guangyuan section), middle (Peng'an section) and lower reaches (Hechuan section) of the Jialing River from June to July, 2016. The lapillus and asteriscus of the left side were used as the study materials. 14 morphometric parameters were measured with traditional methods and transformed into shape indices such as aspect ratio, roundness, format-factor, circularity, rectangularity, ellipticity, etc. Besides, 12 landmarks were established around the rostrum, antirostrum and sulcus of asteriscus by landmark methods. The results showed that the lapillus of S. dabryi was reniform, the morphology had no significant difference among three sections. the asteriscus of S. dabryi was round or oval with a rough surface, the number of knobs was less than 20, the antirostrum was more developed than rostrum, but the central protrusion was not very obvious, the sulcus was teardrop-shaped. Relative warp principal component analysis divided S. dabryi asteriscus of three sections into two types, Type Ⅰ and Type Ⅱ. Type Ⅰ Ⅰcontains the upstream of Jialing River S. dabryi asteriscus samples, while Type Ⅱ includes the middle and lower reaches of Jialing River S. dabryi asteriscus samples. The comprehensive results of traditional morphological method and landmark method showed the morphological differences of the two types were mainly reflected in the overall contour, the knob number, the basal leaf (landmark 6, 7), the sulcus (landmark 10, 11, 12) and the widest point of ventral side (landmark 8). The discriminant analysis results showed that the correct classification could reach 95.5% between two types. The asteriscus of S. dabryi from different river sections of Jialing River can be divided into two significantly different types, which may be related to the adaptation of environmental factors such as water temperature and flow velocity, for example, the slender Ⅰasteriscus of Type Ⅰ with more knobs could be better adapted to the changeful rapids environment at low temperature of upstream.

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