温度突变对大海马(Hippocampus kuda)幼体生长、组分及酶活力的影响   总被引：1，自引：0，他引：1  

孙彬  陈舜  徐永健  戴广谱 《海洋与湖沼》2012,43(1):67-72

以大海马幼体为实验材料,通过设置不同的温度突变组(温度从23℃突变至15℃、28℃和33℃)的方法,对其生长、生化组分以及酶活力的影响进行了研究。结果表明,实验结束后,28℃温度组的大海马幼体生长指标、蛋白含量、能值显著高于23℃对照组(P<0.05),而15℃、33℃温度组的各项指标则显著低于对照组(P<0.05);此外,温度突变组的大海马幼体的酶活力均有先升后降的趋势,在1d后出现峰值,4—6d各个温度组趋于稳定,到实验第15天时,28℃温度组的SOD、ACP活力和MDA的含量已处于23℃对照组水平(P>0.05),CAT、AKP活力显著高于23℃对照组(P<0.05)。而15℃、33℃温度组的SOD、CAT活力降至低于23℃对照组水平(P<0.05),15℃温度组的ACP、AKP活力则低于23℃对照组水平(P<0.05),MDA的含量在15℃、33℃温度组随时间延长而增加。  相似文献   

Modelling mussel growth in ecosystems with low suspended matter loads using a Dynamic Energy Budget approach     

P. Duarte  M.J. Fernández-ReirizU. Labarta 《Journal of Sea Research》2012,67(1):44-57

The environmental and the economic importance of shellfish stimulated a great deal of studies on their physiology over the last decades, with many attempts to model their growth. The first models developed to simulate bivalve growth were predominantly based on the Scope For Growth (SFG) paradigm. In the last years there has been a shift towards the Dynamic Energy Budget (DEB) paradigm. The general objective of this work is contributing to the evaluation of different approaches to simulate bivalve growth in low seston waters by: (i) implementing a model to simulate mussel growth in low suspended matter ecosystems based on the DEB theory (Kooijman, S.A.L.M., 2000. Dynamic and energy mass budgets in biological systems, Cambridge University Press); (ii) comparing and discussing different approaches to simulate feeding processes, in the light of recently published works both on experimental physiology and physiology modeling; (iii) comparing and discussing results obtained with a model based on EMMY (Scholten and Smaal, 1998). The model implemented allowed to successfully simulate mussel feeding and shell length growth in two different Galician Rias. Obtained results together with literature data suggest that modeling of bivalve feeding should incorporate physiologic feed-backs related with food digestibility. In spite of considerable advances in bivalve modeling a number of issues is yet to be resolved, with emphasis on the way food sources are represented and feeding processes formulated.  相似文献   

Growth response of three globose cacti to radiation and soil moisture: An experimental test of the mechanism behind the nurse effect     

Alejandra Martínez-Berdeja  Teresa Valverde   《Journal of Arid Environments》2008,72(10):1766-1774

Cactus seedlings often establish under nurse plants which modify environmental conditions by increasing moisture and decreasing solar radiation, which may cause beneficial and detrimental effects, respectively, on seedling growth. Three soil moisture treatments (5%, 25% and 60%) and two solar radiation levels (100% exposure=243 μmol m⁻² s⁻¹, and 40%=102 μmol m⁻² s⁻¹) were used in a factorial design to analyze seedling growth response of three rare cactus species (Mammillaria pectinifera, Obregonia denegrii and Coryphantha werdermannii). The variables evaluated were relative growth rate (RGR), root/shoot ratio (R/S), and K (RGR_roots/RGR_shoot), obtained from an initial seedling harvest (6-month-old seedlings) and a final harvest 6 months after treatment application. All three species had slow RGRs (0.002–0.012 g g⁻¹ day⁻¹). O. denegrii had the lowest RGR values, but was the only species for which R/S and K varied with soil moisture. While all seedlings responded markedly to soil moisture, no response was observed to radiation treatments. The latter might have been related to the relatively low solar radiation levels present in the greenhouse. Yet, our results suggest that the main benefit nurse plants offer to seedlings is the increase in soil moisture.  相似文献   

Arsenite Resistance,Accumulation, and Volatilization Properties of Trichoderma asperellum SM‐12F1, Penicillium janthinellum SM‐12F4, and Fusarium oxysporum CZ‐8F1          下载免费PDF全文

Qiufen Feng  Shiming Su  Xibai Zeng  Yangzhu Zhang  Lianfang Li  Lingyu Bai  Ran Duan  Zhiling Lin 《洁净——土壤、空气、水》2015,43(1):141-146

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Optical Dating Equivalent Dose (De) Comparison of Global Standardised Growth Curve (gSGC) and Single-aliquot Regenerative-dose (SAR) Methods for Quartz Grains     

Yang Hongyu  Zhao Hui  Wang Xingfan  Geng Jianwei 《地球科学进展》2017,32(10):1111-1118

Optical dating is a method of measuring the time since the sample was buried from last thermal event or light exposure. Samples such as quartz and feldspar grains are the most commonly used sediment of measurement. Single-Aliquot Regenerative-dose (SAR) method has become the most acceptable procedure for obtaining the equivalent Dose (D_e) of a sample. The Standardised Growth Curve (SGC) method provides a possible procedure for measuring a large number of samples; the limitation is that the growth curve fitted by different samples or even different aliquots is divergent. The global Standardised Growth Curve (gSGC) method improves the shortage by normalizing the dose response curves using one regenerative dose OSL signal. The gSGC provides a possible method for obtaining the D_e value of the sample efficiently and quickly. However, due to the radiation dose rate, operating procedures and instrument error and the selected regenerative-dose normalized dose value, etc., each laboratory should develop their own gSGC which has unique parameters. This study established the gSGC curve and measurement process of our laboratory, and then compared the consistency of the equivalent Dose (D_e) values from gSGC and SAR methods. In gSGC procedure, the D_e value of an aliquot can be estimated from the nature signal, one regenerative dose signal and their corresponding test dose signal. It will speed up the optical dating measurement rate of our laboratory and provide reference to establish gSGC in other laboratories. It is found that in the low dose range (0~100 Gy) the obtained D_e values were well consistent by gSGC and SAR methods. There were obviously differences in the higher dose range (>100 Gy) compared to the SAR results. It may be due to the insufficient number of older samples used to fit gSGC in this study. It is necessary to gradually accumulate more samples to improve the gSGC parameters in the future work. For some aliquots, individual quartz grains do not follow the global standardised growth curve, which leads to some deviations of D_e from gSGC. However, these two methods could obtain the similar average De value when multiple aliquots measuring.  相似文献   

Single Nucleotide Polymorphism of FSHβ Gene Associated with Reproductive Traits in Japanese Flounder (Paralichthys olivaceus)     

Feng He  Haishen Wen  Dahui Yu  Jifang Li  Bao Shi  Caifang Chen  Jiaren Zhang  Guoxiong Jin  Xiaoyan Chen  Dan Shi  Yanping Yang 《中国海洋大学学报(英文版)》2010,9(4):395-398

Follicle stimulating hormone β (FSHβ) of Japanese flounder (Paralichthys olivaceus) plays a key role in the regulation of gonadal development.This study aimed to investigate molecular genetic characteristics of the FSHβ gene and elucidate the effects of single nucleotide polymorphisms (SNPs) of FSHβ on reproductive traits in Japanese flounder.We used polymerase chain reaction single-strand conformation polymorphism (PCR-SSCP) and sequencing of the FSHβ gene in 60 individuals.We identified only an SNP (T/C) in the coding region of exon3 of FSHβ.The SNP (T/C) did not lead to amino acid changes at the position 340 bp of FSHβ gene.Statistical analysis showed that the SNP was significantly associated with testosterone (T) level and gonadosomatic index (GSI) (P0.05).Individuals with genotype TC of the SNP had significantly higher serum T levels and GSI (P0.05) than that of genotype CC.Therefore, FSHβ gene could be a useful molecular marker in selection for prominent reproductive trait in Japanese Flounder.  相似文献   

Latitudinal variation of leaf morphological traits from species to communities along a forest transect in eastern China   总被引：2，自引：0，他引：2  

Ruili Wang  Guirui Yu  Nianpeng He  Qiufeng Wang  Ning Zhao  Zhiwei Xu 《地理学报(英文版)》2016,26(1):15-26

Comprehensive information on geographic patterns of leaf morphological traits in Chinese forests is still scarce. To explore the spatial patterns of leaf traits, we investigated leaf area (LA), leaf thickness (LT), specific leaf area (SLA), and leaf dry matter content (LDMC) across 847 species from nine typical forests along the North-South Transect of Eastern China (NSTEC) between July and August 2013, and also calculated the community weighted means (CWM) of leaf traits by determining the relative dominance of each species. Our results showed that, for all species, the means (± SE) of LA, LT, SLA, and LDMC were 2860.01 ± 135.37 mm², 0.17 ± 0.003 mm, 20.15 ± 0.43 m² kg^–1, and 316.73 ± 3.81 mg g^–1, respectively. Furthermore, latitudinal variation in leaf traits differed at the species and community levels. Generally, at the species level, SLA increased and LDMC decreased as latitude increased, whereas no clear latitudinal trends among LA or LT were found, which could be the result of shifts in plant functional types. When scaling up to the community level, more significant spatial patterns of leaf traits were observed (R ² = 0.46–0.71), driven by climate and soil N content. These results provided synthetic data compilation and analyses to better parameterize complex ecological models in the future, and emphasized the importance of scaling-up when studying the biogeographic patterns of plant traits.  相似文献   

The aquaculture potential of Tilapia rendalli in relation to its feeding habits and digestive capabilities     

《Physics and Chemistry of the Earth》2013

Tilapia rendalli is a predominately macrophagous fish. However, it was able to colonise an oligotrophic dam (Flag Boshielo) with limited macrophytes. Therefore, the diet of T. rendalli in this dam was investigated; its stomach contents were examined over 12 months. A size related dietary shift was evident. Juveniles fed mainly on zooplankton while sub-adult and adult fish grazed on both macrophytes and marginal vegetation. T. rendalli’s ability to strive in an environment with limited food resources led to a subsequent study to determine its aquaculture potential. Its growth performance was compared to that of the commonly cultured Oreochromis mossambicus. Juveniles of both species were fed a commercial tilapia diet for 60 days. Specific growth rate and protein efficiency ratio was comparable to that of O. mossambicus (P > 0.05, ANOVA). Feed conversion ratio was significantly higher (P < 0.05) in T. rendalli (1.43) than in O. mossambicus (1.25) indicating a better efficiency in feed utilisation by O. mossambicus. At a physiological level, protease, lipase and cellulase activities did not differ significantly between the two fish species (P > 0.05). Amylase activities were significantly higher (P < 0.05) in T. rendalli than in O. mossambicus. The highest amylase activities were recorded in the proximal intestines as 26.34 and 22.00 μmol/min/mg protein in T. rendalli and O. mossambicus respectively. This may be an indicator that T. rendalli is better equipped to digest plant diets. T. rendalli may be the aquaculture species of choice for emerging fish farmers who cannot afford the highly priced fishmeal as a protein source in fish diets.  相似文献   

Prediction of the consumption rates for juvenile Atlantic salmon (Salmo salar L.) on the scale of habitat patches: Development of empirical models based on stomach contents     

Frédéric Burton  Daniel Boisclair 《Limnologica》2013,43(5):332-338

Rivers and streams are unstable environments in which estimation of energetic costs and benefits of habitat utilization are the daunting exercise. Empirical models of food consumption may be used to estimate energetic benefits based on abiotic and biotic conditions in patches of habitat. We performed thirty daily surveys of fish stomach contents to estimate the consumption rates for juvenile Atlantic salmon (Salmo salar) in a river. The data were used to assess whether variations of daily consumption rates existed within the river, and to develop empirical models that could predict fish consumption rates using abiotic and biotic conditions as independent variables. Daily consumption rates based on stomach content surveys in the field (range: 0.15–1.49 g dry/(100 g wet day)) varied significantly depending on habitat patch (500–1000 m²), summer period, and sampling year. Variables such as water temperature, numerical density of salmon, water depth and moon phase explained 83–93% of the variations in daily food consumption rates. Daily consumption rates tended to increase with water temperature and depth, and were also higher near a full moon. However, they tended to decrease with the numerical density of salmon. Our work suggests that empirical models based on independent variables that are relatively simple to estimate in the field may be developed to predict fish consumption rates in different habitat patches in a river.  相似文献   

Nonmodal Growth on a Sphere at Various Horizontal Scales     

Richard Grotjahn  Cris Castello 《地球物理与天体物理流体动力学》2013,107(3):223-238

Nonmodal growth (NG) and unstable normal mode growth are considered in spherical geometry. Two groups of initial conditions (IC) are studied: "connected" IC (common in Cartesian studies) and "separated" IC (based on observed conditions prior to cyclogenesis). Time series of growth rates are emphasized in conjunction with eigenmode projections. Projections show that early on normal mode growth was much stronger for connected IC and that NG caused negative growth early on of some variables for separated IC. Projections explain why amplitude, kinetic energy (KE), and potential vorticity have more NG than available potential energy (APE). Though varying between ICs and with initial phase shift, NG increases with wavenumber. For middle wavelengths, NG is significant and positive using connected IC but negative or small using separated IC. Total energy and KE growth rates of short waves are very similar during the first 2 days for both ICs. Amplitude time series closely follow KE in all cases studied. APE has less overlap than does KE between the main modes present, so less NG occurs for APE than for KE. In separated IC cases, APE growth rates evolve consistent with emergence of an unstable normal mode and little NG.  相似文献