[Objective] The experiment aimed to explore the influences of phytohormones (ABT and IAA) and nutrient solution on rooting of Abies beshanzuensis M.H.Wu by water cultured medium. [Method] The Abies beshanzuensis M.H.W...[Objective] The experiment aimed to explore the influences of phytohormones (ABT and IAA) and nutrient solution on rooting of Abies beshanzuensis M.H.Wu by water cultured medium. [Method] The Abies beshanzuensis M.H.Wu were treated by water (CK), 10 mg/L ABT+ water, 10 mg/L IAA+ water, 10 mg/L ABT+ hoagland solution, 10 mg/L IAA+ hoagland solution, then the rooting process was observed and the formation rate of callus, rooting rate, number of rooting, and root length were investigated and analyzed. [Result] ABT and IAA had obvious influences on callus induction, rooting rate and the number of root of Abies beshanzuensis M.H.Wu by water culture, so they were suitable to be used in water propagation of Abies beshanzuensis M.H.Wu. The treatments of phytohormones had no regular influences on the longest root length and average root length. The nutrient solutions would not generate obvious influence on propagation of Abies beshanzuensis M.H.Wu at firstly stage, but they generated influence on root growth after rooting. [Conclusion] The research provided new ideas for propagation of Abies beshanzuensis M.H.Wu, which could make it out of endangerment situation quickly.展开更多
To solve the problems of microbial contamination and no rooting during the tissue culture of Huperzia serrata, wild seedlings of Huperzia serrata were cultured by indoor hydroponics or soil cultivation methods, then t...To solve the problems of microbial contamination and no rooting during the tissue culture of Huperzia serrata, wild seedlings of Huperzia serrata were cultured by indoor hydroponics or soil cultivation methods, then the stem tips were used in tissue culture. The above operation significantly reduced microbial contamination during tissue culture process. Different types and concentrations of hormones were added into the basic medium MS to screen the optimal formula for induced plantlet growth and rooting. It was found that 1/2MSCO was the best medium on which stem, leaves and roots of tissue culture plantlets of Huperzia serrata grew quickly. At the same time, sand planting was a convenient and effective approach for gemmae propagation of Huperzia serrata, the survival rate of seedlings germinated from gemmae was nearly 100%.展开更多
The current study explored Aurelia aurita and Rhopilema esculent um consumption by silver pomfret juveniles, as well as their prey selection between the two jellyfi sh species. Silver pomfret juveniles weighing 1±...The current study explored Aurelia aurita and Rhopilema esculent um consumption by silver pomfret juveniles, as well as their prey selection between the two jellyfi sh species. Silver pomfret juveniles weighing 1±0.1 g actively preyed on both the species. Their daily A. aurita consumption was 11.6 times their own body weights regardless of the size of A. aurita medusae. Their daily R. esculent um consumption was 13, 9.1, 5, and 4.1 times their own body weights when the R. esculentum medusae were 10, 20, 30, and 40 mm in bell diameter, respectively. The survival rates of the R. esculent um were higher than those of the A. aurita. When the R. esculent um medusae were more than 30 mm in bell diameter, their survival rate exceeded 92%. Silver pomfrets serve as a type of potential predators on A. aurita in coastal waters, and they have little infl uence on R. esculent um with a size exceeding 30 mm. Besides, A. aurita may be able to be used as fi sh prey in silver pomfret artifi cial breeding.展开更多
A technique for modelling of three-dimensional(3D)quasi-statically propagating cracks in elastic bodies by the displacement discontinuity method(DDM)was described.When the crack is closed,the Mohr-coulomb rule on the ...A technique for modelling of three-dimensional(3D)quasi-statically propagating cracks in elastic bodies by the displacement discontinuity method(DDM)was described.When the crack is closed,the Mohr-coulomb rule on the two contacted surfaces of the crack must be satisfied.A simple iterative method was adopted in order to consider three different states of cracks.Under the assumption that the advance of the point on the crack front would occur only in the normal plane which is through this edge point,the maximum energy release rate criterion is modified to be used as the criterion for the crack growth.With discretization,the process of crack propagation can be seen as the advance of the vertices of the crack front.The program MCP3D was developed based on these theories to simulate the 3D quasi-static crack propagation.A numerical example of a penny-shaped crack subject to tension and compression in an infinite elastic media was analyzed with MCP3D,and the results in comparison with others' show that the present method for 3D crack propagation is effective.展开更多
Since the 1990s, artificial propagation and breeding technique of marine fish in China have developed by way of increasing species and fry numbers, with special stress laid on valuable species. Large quantities of art...Since the 1990s, artificial propagation and breeding technique of marine fish in China have developed by way of increasing species and fry numbers, with special stress laid on valuable species. Large quantities of artificial fry can meet the needs of both marine cage culture and pond culture for most species. Experimental results obtained by scientists have been put into use in actual production. Fish fry production has entered a period of sustainable development. So far, at least 44 species (21 families) of marine fish have been successfully bred in China. The artificial fry number of large yellow croaker (Pseudosciaena crocea) exceeded 300 million in 1999. The species whose artificial fry numbers have each surpassed 10 million annually are red drum (Sciaenops ocellatus), Japanese seabass (Lateolabrax japonicus), cuneate drum (Nibea miichthioides), spring spawning red seabream (Pagrosomus major) and threebanded sweetlip (Plectorhynchus cinctus). Millions of artificial fry are bred annually in the species of black porgy (Sparus macrocephalus), Russell’s snapper (Lutjanus russelli), javelin grunt (Pomadasys hasta), miiuy croaker (Miichthys miiuy) and skewband grunt (Hapalogenys nitens). The fish in the family Sciaenidae are the main species in artificial propagation and breeding. Some problems and prospects on marine fish culture and stock enhancement are also discussed and some proposals for sustainable development are put forward in this article.展开更多
In worldwide, the most common triggering factor of rock landslides is extended and intense rainfall. However, different from the soil slope failure caused by softening action of infiltration rainwater, the mechanism o...In worldwide, the most common triggering factor of rock landslides is extended and intense rainfall. However, different from the soil slope failure caused by softening action of infiltration rainwater, the mechanism of rock landslide in rainfall is not clear. From the view of fracture mechanics, the propagation of cracks on rock slope and the development of sliding surface were researched. Then based on hydraulics formulas and using Sweden arc method, the influence of crack water on stability of rock slope was quantitatively studied. Finally, an example was given to check the theoretical approach. The result shows that the development of sliding surface of rock slope is mainly caused by crack propagation under hydrostatic pressure when the stress intensity factor KI at crack tip is bigger than the toughness index of rock fractures Klc, and the failure of slope is the result of hydraulic action of crack water and the softening of materials on sliding surface when the depth of crack water is bigger than a minimum value hmin.展开更多
The rice water weevil, Lissorhoptrus oryzophilus Kuschel, has two generations in southern Zhejiang, China. To determine oogenesis in first-generation females (summer females) and its relations to temperature, female...The rice water weevil, Lissorhoptrus oryzophilus Kuschel, has two generations in southern Zhejiang, China. To determine oogenesis in first-generation females (summer females) and its relations to temperature, females were collected from a rice field in early and mid-July and reared on young rice plants at 28, 31 and 34 ℃ in the laboratory. Percentage of females having oocytes, number of oocytes of different stages (stage-Ⅰ, from early previtellogenesis to middle vitellogenesis; stage-Ⅱ, late vitellogenesis; and matute-oocyte stage), and length of ovarioles were determined every 10 d of feeding. At each temperature, oogenesis took place in over 40% of females after 20-40 d of feeding, but only 0.0-3.3 stage-Ⅰ, 0.0-0.8 stage-Ⅱ and 0.0-1.1 mature oocytes were observed at each observation date. Temperature had significant effect on number of stage-Ⅰ oocytes but not on number of stage-Ⅱ and mature oocytes in early July females; temperature had no significant effect on number of oocytes of either stage in mid-July females. Conclusively, in southern Zhejiang, summer L. oryzophilus females have great potential to become reproductive on rice, but their oogenesis activity is very low, with the overall procedures little affected by temperature.展开更多
An ecological project called fish biomanipulation, other than the conventional fishery culture technique, was put forward in this paper for the excess propagation control of Cyclops. The control effects on Cyclops of ...An ecological project called fish biomanipulation, other than the conventional fishery culture technique, was put forward in this paper for the excess propagation control of Cyclops. The control effects on Cyclops of four species of fish were investigated experimentally at stocking density of 30 g per cubic meter of water. The experimental results showed that the food habit of the fish had significant influence on the biological control of Cyclops. The propagation of Cyclops could be controlled effectively and also the water quality was improved simultaneously by stocking the filter-feeding fishes, such as silver carp and bighead carp. Whereas, herbivorous Ctenopharyugodon idellus and omnivorous Cyprinus carpio had no obvious biological effects on controlling the growth of Cyclops and restoring water quality. The results further proved that under condition of proper poly-culture density of silver carp and bighead carp, the number of Cyclops might be controlled at very low level and the eutrophication might be abated by removing the nutrients from water body.展开更多
Objective The experiment was conducted to explore the effects of silymarin on reproductive and lactation performance,serum antioxidants,and body metabolism of sows.Methods Sixty pregnant sows(85 d,Large×Landrace)...Objective The experiment was conducted to explore the effects of silymarin on reproductive and lactation performance,serum antioxidants,and body metabolism of sows.Methods Sixty pregnant sows(85 d,Large×Landrace)with similar genetic background,body condition,and parity were randomly divided into three groups,and each group has 20 individually housed sows.The sows in the control group(CG)were fed with basal diet,and those in the experimental group A(EGA)and B(EGB)were fed with basal diet containing 250 and 500 mg/kg silymarin,respectively.The experiment lasted 46 days from day 85 of gestation to the end of lactation(weaning on day 17).The milk composition and serum biochemical para-meters were determined by a milk composition analyzer and a blood biochemical analyzer,respectively.Serum antioxidant indexes and plasma hormone levels were measured using the biochemical kits.The gas chromatograph was applied to detect the fecal short chain fatty acids.Results Compared with the CG,the total feed intake(TFI)and average daily feed intake(ADFI)were significantly increased(P<0.01),and the urea content in regular milk tended to increase(P=0.095)in the EG.The serum malondialdehyde(MDA)contents were decreased on day 90 of gestation and the day of farrowing(P<0.01),and the serum contents of total antioxidant capacity(T-AOC)tended to increase on day 17 of lactation(P=0.099)compared with the CG.Compared with the CG,the serum triglyceride(TG)concentrations in the EG tended to increase on day 90 of gestation(P=0.062),and the content of serum total protein(TP)and albumin(ALB)reduced on day 17 of lactation(P<0.01).Compared with the CG,plasm D-lactic acid content was decreased(P<0.05),and the plasma prostaglandin(PG)level tended to increase(P=0.088)in the EG on the day of farrowing and day 17 of lactation.Compared with the CG,fecal isobutyric acid concentration in the EG significantly decreased on the day of farrowing(P<0.05).Conclusion Adding 250-500 mg/kg silymarin to diets from the late gestation to the end of lactation could improve reproductive and lactation performance of sows via the regulation of nutrient metabolism and serum antioxidant.展开更多
In field and laboratory conditions the reproductive potential (survival at different stages of development) of the Colorado potato beetle has been measured, the dependence of the parameters of insects fertility on v...In field and laboratory conditions the reproductive potential (survival at different stages of development) of the Colorado potato beetle has been measured, the dependence of the parameters of insects fertility on varietal features of the feed has been investigated, the food activity of the representatives of insects from four areas of the Southern Urals has been measured, the intensity and time of hypersensitivity reactions on potato leaves has been defined. In laboratory experiments, the level of activity of hydrolytic enzymes in insects and the level of activity of these enzymes inhibitors in the leaves of three potato varieties differing in their resistance to the Colorado potato beetle have been determined. The results show that the insects-representatives of different samples have different food activity in relation to different potato varieties. High mortality rates were revealed at feeding with leaves of potato of the Bashkir variety characterized by a high level of hydrolases inhibitors and relatively rapid development of necrotic reactions after the appearance of eggs laying on the leaves. We suppose that the neerogenetic barrier appearing in the form of necrosis is the major cause of the fetal mortality of insects. The level of the content of inhibitors inactivating larvae digestive enzymes affects the survival of insects at postembryonic stages. The speed of the necrosis emergence, the level of activity of digestive enzymes inhibitors in potato can be considered as criteria for the selection of breeding material for resistance to the Colorado potato beetle.展开更多
The effectiveness of a magnetic ion exchange resin (MIEX) for the treatment of Hongze Lake water in China was evaluated, The kinetics of natural organic matter (NOM) removal at various MIEX doses and contact time,...The effectiveness of a magnetic ion exchange resin (MIEX) for the treatment of Hongze Lake water in China was evaluated, The kinetics of natural organic matter (NOM) removal at various MIEX doses and contact time, multiple-loading experiments, impacts of MIEX prior to coagulation on coagulant demands and the effectiveness of combination of MIEX, pre-chlorination and coagulation were investigated. Kinetic experimental results show that more than 80% UV254 and 67% dissolved organic carbon (DOC) from raw water can be removed by the use of MIEX alone. 94% sulfate, 69% nitrate and 98% bromide removals are obtained after the first use of MIEX in multiple-loading experiments. It is suggested that MIEX can be loaded up to 1 250 bed volume (BV, volume ratio of tested water to resin) or more without saturation when regarding organics removal as a target. MIEX can remove organics to a greater extend than coagulation and lower the coagulant demand when combining with coagulation. Chlorination experimental results show that MIEX can remove 57% chlorine demand and 77% trihalomethane formation potential (THMFP) for raw water. Pre-chlorination followed by MIEX and coagulation can give additional organic and THMFP removals. The results suggest that MIEX provides a new method to solve thc problem algae reproduction.展开更多
Hybrid tilapia weighing 7.71 g were reared in seawater at 24.0-29.0℃ for 8 weeks. The controls were fed to satiation twice a day throughout the experiment, whereas treatment groups were fed at 0.5%, 1.5% or 3.0% body...Hybrid tilapia weighing 7.71 g were reared in seawater at 24.0-29.0℃ for 8 weeks. The controls were fed to satiation twice a day throughout the experiment, whereas treatment groups were fed at 0.5%, 1.5% or 3.0% body weight per day for 4 weeks, and then to satiation for the remainder of the experiment. During the first 4-week period, there was a curvilinear relationship between growth rate and ration size. Fish fed 0.5% and 1.5% rations displayed compensatory growth response of 2 weeks duration during realimentation. The weight-adjusted growth rate of fish fed at 3% ration was not significantly different from that of the controls by the end of the experiment, when none of the treatment groups had caught up in body weight with the controls. Hyperphagia was observed for the first 2 weeks of realimenatation in fish previously fed at 3% ration, but persisted for the whole realimentation period in groups previously fed at 0.5% and 1.5% rations. None of the feed restricted groups showed improved digestibility, feed efficiency, or protein and energy retention efficiency.展开更多
The classification and inheritance of rice starch RVA profiles were studied by testing RVA profiles of F2 clonally propagated population and some varieties, including japonica, indica, and glutinous types. All the RVA...The classification and inheritance of rice starch RVA profiles were studied by testing RVA profiles of F2 clonally propagated population and some varieties, including japonica, indica, and glutinous types. All the RVA profiles of accessions could be divided into six kinds based on the cluster analysis, that is A, B, C, D, E and F. Feature profile of sticky variety was type A. The profiles of indica varieties could be presented as B, C, D, E and F types and that of japonica varieties fell into D, E and F types.RVA profiles of the rice were mainly affected by apparent amylose content (AAC), but the difference of RVA profiles could also be detected in the varieties with similar AAC. The close relationship between RVA profile indices and sensory of low or middle AAC varieties suggested that the RVA profiles can be used as indirect index to evaluate eating and cooking quality. In four hybrid combinations, the component indices of RVA profiles of F1 were between those of its parents except peak viscosity and pasting temperature. Also, in F2 clonally propagated population, all the components of the RVA profiles showed continuous segregation,suggesting that all of them were controlled by a series of minor genes, although Wx gene may play an important role in determining the RVA profiles. These results may provide some new information useful for rice quality breeding program.展开更多
The use of multisensory cues to locate mates can increase an organism's success by acting as a back-up plan when one system fails, by providing additional information to the receiver, and by increasing their ability ...The use of multisensory cues to locate mates can increase an organism's success by acting as a back-up plan when one system fails, by providing additional information to the receiver, and by increasing their ability to detect mates using senses that have different ranges in a variable aquatic environment. In this contribution we review the sensory cues that male horseshoe crabs Lirnulus polyphemus are known to use when locating mates and then provide new data that shed light on this subject. Dur- ing the breeding season, females migrate into shore during high tides to spawn. Males attach to females as they approach the beach or are attracted to pairs already spawning. Vision is well established as an important cue in attracting males. Although chemoreception is well known in other marine arthropods, and horseshoe crabs have the anatomy available, there are few studies on chemical cues in this species. Experiments are presented here that provide evidence for chemical cue use. We show that the attraction, and retention, of attached and satellite males to actively spawning females and mating pairs involves multimodal cues展开更多
Studying gonadal development of annual cycle can reveal the process of gametogenesis and reproductive period, and evaluate fertility and source utilization of a species. Host sea anemones are conspicuous members of tr...Studying gonadal development of annual cycle can reveal the process of gametogenesis and reproductive period, and evaluate fertility and source utilization of a species. Host sea anemones are conspicuous members of tropical and subtropical reef ecosystems, but little is known about its biology including reproductive seasonality. Here we reported a one-year study on the gametogenesis and reproduction of host sea anemone(Entacmaea quadricolor) inhabiting Hong Kong waters. E. quadricolor tissues were sampled in 12 occasions from 5 m and 15 m depths of water, respectively. Histological sectioning of the tissues showed that E. quadricolor was dioecious, and populational ratio of female to male was 1:1.6. The gonadal development was asynchronous within an annual cycle, which included proliferating, growing, maturing, spawning, and resting stages. The spawning occurred between August and October when surface seawater temperature reached the annual maximum(28℃), suggesting that temperature is an important factor modulating the gonadal development and mature of E. quadricolor.展开更多
Seagrass decline caused by the macroalgae blooms is becoming a common phenomenon throughout temperate and tropical regions. We summarized the incidence of macroalgae blooms throughout the world and their impact on sea...Seagrass decline caused by the macroalgae blooms is becoming a common phenomenon throughout temperate and tropical regions. We summarized the incidence of macroalgae blooms throughout the world and their impact on seagrass beds by direct and indirect ways. The competition for living space and using resources is the most direct effect on seagrass beds when macroalgae are blooming in an aquatic ecosystem. The consequence of macroalgae blooms(e.g., light reduction, hypoxia, and decomposition) can produce significant indirect effects on seagrass beds. Light reduction by the macroalgae can decrease the growth and recruitment of seagrasses, and decomposition of macroalgae mats can increase the anoxic and eutrophic conditions, which can further constrict the seagrass growth. Meanwhile, the presence of seagrass shoots can provide substrate for the macroalgae blooms. Controlling nutrient sources from the land to coastal waters is a general efficient way for coastal management. Researching into the synergistical effect of climate change and anthropognic nutrient loads on the interaction between searsasses and macroalgae can provide valuable information to decrease the negative effects of macroalgae blooms on seagrasses in eutrophic areas.展开更多
Breeding and mass scale larval rearing of clownfish Amphiprion percula is very limited in brackishwater. We designed an indoor program of A. percula culture in brackishwater with a salinity of 24±1, during which ...Breeding and mass scale larval rearing of clownfish Amphiprion percula is very limited in brackishwater. We designed an indoor program of A. percula culture in brackishwater with a salinity of 24±1, during which the impacts of feed type, water temperature, and light intensity, on the efficiency of its reproduction, were revealed. The fish were accommodated along with sea anemones in fibre glass tanks to determine the influence of brooder diet on breeding efficiency. Higher reproductive efficiency [number of eggs laid (276±22.3 eggs)] was observed when fish were fed live Acetes sp. rather than clam (204±16.4 eggs), trash fish (155±12 eggs) and formulated feed (110±10 eggs). The spawning rate was increased during September and October (water temperature, 28.74±0.55℃) on average of 2.4 spawning per month; and low spawning rate was in January (water temperature, 24.55±0.45℃) on average of I spawning per month. Among three light intensities (100, 500, and 900 1x) set to evaluate larval survival rate, larvae showed the highest survival rate (65.5%) at 900 lx. The breeding method specifically in brackishwater developed in the present study is a new approach, will help the people from the regions of estuary and backwater to enhance their livelihood and it will lead to reduce the exploitation from the wild habitat.展开更多
Cherry regeneration via somatic embryogenesis is a powerful tool to breeding. In this way, the embryogenic capacity of Prunus incisa specie has been tested from leaves under different interactions of picloram concentr...Cherry regeneration via somatic embryogenesis is a powerful tool to breeding. In this way, the embryogenic capacity of Prunus incisa specie has been tested from leaves under different interactions of picloram concentrations and darkness exposures. Induction culture was achieved on MS medium supplemented with picloram concentrations at 0.5, 1 and 1.5 mg.L1 and submitted to 10, 20, 30 and 40 days of darkness. The best rate of embryogenic leaves was obtained with the interaction of 30 days darkness exposure* 1 mg.L^-1 picloram. According to their age, leaves were differently reacted to somatic embryogenesis; indeed, the 2nd expanded leaf from the apex was the most embryogenic one. Concerning the effect of additional auxin to picloram (1 mg·L^-1), IAA at 0.1 mg·L^-1 and IBA at 0.1 mg·L^-1 gave significantly higher induction rates than all other concentrations, but regenerating somatic embryos showed some teratological abnormalities probably due to seconda;y embryogenesis. At the opposite, NAA at 0.5 mg·L^-1 didn't improve embryogenic rate but affected positively embryo development. Furthermore, embryogenesis preferentially took place on the basal part of leaf. Satisfactory rates of somatic embryogenesis are obtained but further improvement remains possible.展开更多
基金Supported by Science and Technology Plan of Zhejiang Province(2005C32036)National Natural Science Foundation of China(30700644)~~
文摘[Objective] The experiment aimed to explore the influences of phytohormones (ABT and IAA) and nutrient solution on rooting of Abies beshanzuensis M.H.Wu by water cultured medium. [Method] The Abies beshanzuensis M.H.Wu were treated by water (CK), 10 mg/L ABT+ water, 10 mg/L IAA+ water, 10 mg/L ABT+ hoagland solution, 10 mg/L IAA+ hoagland solution, then the rooting process was observed and the formation rate of callus, rooting rate, number of rooting, and root length were investigated and analyzed. [Result] ABT and IAA had obvious influences on callus induction, rooting rate and the number of root of Abies beshanzuensis M.H.Wu by water culture, so they were suitable to be used in water propagation of Abies beshanzuensis M.H.Wu. The treatments of phytohormones had no regular influences on the longest root length and average root length. The nutrient solutions would not generate obvious influence on propagation of Abies beshanzuensis M.H.Wu at firstly stage, but they generated influence on root growth after rooting. [Conclusion] The research provided new ideas for propagation of Abies beshanzuensis M.H.Wu, which could make it out of endangerment situation quickly.
文摘To solve the problems of microbial contamination and no rooting during the tissue culture of Huperzia serrata, wild seedlings of Huperzia serrata were cultured by indoor hydroponics or soil cultivation methods, then the stem tips were used in tissue culture. The above operation significantly reduced microbial contamination during tissue culture process. Different types and concentrations of hormones were added into the basic medium MS to screen the optimal formula for induced plantlet growth and rooting. It was found that 1/2MSCO was the best medium on which stem, leaves and roots of tissue culture plantlets of Huperzia serrata grew quickly. At the same time, sand planting was a convenient and effective approach for gemmae propagation of Huperzia serrata, the survival rate of seedlings germinated from gemmae was nearly 100%.
基金Supported by National Basic Research Program of China(973 Program)(No.2011CB403605)the Key Science and Technology Program of Qingdao(No.11-3-1-6-hy)+1 种基金the Special Funds for the Basic R&D Programin the Central Non-Profit Research Institutes(No.20603022011008)the National Key Technology R&D Program during the Twelfth Five-Year Plan Period(No.2011BAD13B01)
文摘The current study explored Aurelia aurita and Rhopilema esculent um consumption by silver pomfret juveniles, as well as their prey selection between the two jellyfi sh species. Silver pomfret juveniles weighing 1±0.1 g actively preyed on both the species. Their daily A. aurita consumption was 11.6 times their own body weights regardless of the size of A. aurita medusae. Their daily R. esculent um consumption was 13, 9.1, 5, and 4.1 times their own body weights when the R. esculentum medusae were 10, 20, 30, and 40 mm in bell diameter, respectively. The survival rates of the R. esculent um were higher than those of the A. aurita. When the R. esculent um medusae were more than 30 mm in bell diameter, their survival rate exceeded 92%. Silver pomfrets serve as a type of potential predators on A. aurita in coastal waters, and they have little infl uence on R. esculent um with a size exceeding 30 mm. Besides, A. aurita may be able to be used as fi sh prey in silver pomfret artifi cial breeding.
文摘A technique for modelling of three-dimensional(3D)quasi-statically propagating cracks in elastic bodies by the displacement discontinuity method(DDM)was described.When the crack is closed,the Mohr-coulomb rule on the two contacted surfaces of the crack must be satisfied.A simple iterative method was adopted in order to consider three different states of cracks.Under the assumption that the advance of the point on the crack front would occur only in the normal plane which is through this edge point,the maximum energy release rate criterion is modified to be used as the criterion for the crack growth.With discretization,the process of crack propagation can be seen as the advance of the vertices of the crack front.The program MCP3D was developed based on these theories to simulate the 3D quasi-static crack propagation.A numerical example of a penny-shaped crack subject to tension and compression in an infinite elastic media was analyzed with MCP3D,and the results in comparison with others' show that the present method for 3D crack propagation is effective.
文摘Since the 1990s, artificial propagation and breeding technique of marine fish in China have developed by way of increasing species and fry numbers, with special stress laid on valuable species. Large quantities of artificial fry can meet the needs of both marine cage culture and pond culture for most species. Experimental results obtained by scientists have been put into use in actual production. Fish fry production has entered a period of sustainable development. So far, at least 44 species (21 families) of marine fish have been successfully bred in China. The artificial fry number of large yellow croaker (Pseudosciaena crocea) exceeded 300 million in 1999. The species whose artificial fry numbers have each surpassed 10 million annually are red drum (Sciaenops ocellatus), Japanese seabass (Lateolabrax japonicus), cuneate drum (Nibea miichthioides), spring spawning red seabream (Pagrosomus major) and threebanded sweetlip (Plectorhynchus cinctus). Millions of artificial fry are bred annually in the species of black porgy (Sparus macrocephalus), Russell’s snapper (Lutjanus russelli), javelin grunt (Pomadasys hasta), miiuy croaker (Miichthys miiuy) and skewband grunt (Hapalogenys nitens). The fish in the family Sciaenidae are the main species in artificial propagation and breeding. Some problems and prospects on marine fish culture and stock enhancement are also discussed and some proposals for sustainable development are put forward in this article.
基金Project(2008CB425802) supported by the National Basic Research Program of China Project(40872181) supported by the National Natural Science Foundation of ChinaProject(09R2200200) supported by the West Light Foundation of Chinese Academy of Sciences
文摘In worldwide, the most common triggering factor of rock landslides is extended and intense rainfall. However, different from the soil slope failure caused by softening action of infiltration rainwater, the mechanism of rock landslide in rainfall is not clear. From the view of fracture mechanics, the propagation of cracks on rock slope and the development of sliding surface were researched. Then based on hydraulics formulas and using Sweden arc method, the influence of crack water on stability of rock slope was quantitatively studied. Finally, an example was given to check the theoretical approach. The result shows that the development of sliding surface of rock slope is mainly caused by crack propagation under hydrostatic pressure when the stress intensity factor KI at crack tip is bigger than the toughness index of rock fractures Klc, and the failure of slope is the result of hydraulic action of crack water and the softening of materials on sliding surface when the depth of crack water is bigger than a minimum value hmin.
基金Project supported by the National Natural Science Foundation of China (No. 30400290) and the National Basic Research Program(973) of China (No. 2002CB111403)
文摘The rice water weevil, Lissorhoptrus oryzophilus Kuschel, has two generations in southern Zhejiang, China. To determine oogenesis in first-generation females (summer females) and its relations to temperature, females were collected from a rice field in early and mid-July and reared on young rice plants at 28, 31 and 34 ℃ in the laboratory. Percentage of females having oocytes, number of oocytes of different stages (stage-Ⅰ, from early previtellogenesis to middle vitellogenesis; stage-Ⅱ, late vitellogenesis; and matute-oocyte stage), and length of ovarioles were determined every 10 d of feeding. At each temperature, oogenesis took place in over 40% of females after 20-40 d of feeding, but only 0.0-3.3 stage-Ⅰ, 0.0-0.8 stage-Ⅱ and 0.0-1.1 mature oocytes were observed at each observation date. Temperature had significant effect on number of stage-Ⅰ oocytes but not on number of stage-Ⅱ and mature oocytes in early July females; temperature had no significant effect on number of oocytes of either stage in mid-July females. Conclusively, in southern Zhejiang, summer L. oryzophilus females have great potential to become reproductive on rice, but their oogenesis activity is very low, with the overall procedures little affected by temperature.
基金Sponsored by the Hi-Tech Research and Development Program of China (Grant No. 2002AA601140 )the National Science Foundation of Heilongjiang Province (Grant No. QC03C17)the Focal Laboratory Opening Research Program of Beijing and the Scientific Resear
文摘An ecological project called fish biomanipulation, other than the conventional fishery culture technique, was put forward in this paper for the excess propagation control of Cyclops. The control effects on Cyclops of four species of fish were investigated experimentally at stocking density of 30 g per cubic meter of water. The experimental results showed that the food habit of the fish had significant influence on the biological control of Cyclops. The propagation of Cyclops could be controlled effectively and also the water quality was improved simultaneously by stocking the filter-feeding fishes, such as silver carp and bighead carp. Whereas, herbivorous Ctenopharyugodon idellus and omnivorous Cyprinus carpio had no obvious biological effects on controlling the growth of Cyclops and restoring water quality. The results further proved that under condition of proper poly-culture density of silver carp and bighead carp, the number of Cyclops might be controlled at very low level and the eutrophication might be abated by removing the nutrients from water body.
基金National Key Research and Development Program(2021YFD1300201 and 2021YFD1301004)Science and Technology Innovation Program of Hunan Province(2020RC2063)+2 种基金Natural Science Foundation of Hunan Province(2022JJ40532)Open Fund of Key Laboratory of Agro-ecological Processes in Subtropical Region,Chinese Academy of Sciences(ISA2021103)the cooperation between research institutes and enterprises(E0490205 and E0490207).
文摘Objective The experiment was conducted to explore the effects of silymarin on reproductive and lactation performance,serum antioxidants,and body metabolism of sows.Methods Sixty pregnant sows(85 d,Large×Landrace)with similar genetic background,body condition,and parity were randomly divided into three groups,and each group has 20 individually housed sows.The sows in the control group(CG)were fed with basal diet,and those in the experimental group A(EGA)and B(EGB)were fed with basal diet containing 250 and 500 mg/kg silymarin,respectively.The experiment lasted 46 days from day 85 of gestation to the end of lactation(weaning on day 17).The milk composition and serum biochemical para-meters were determined by a milk composition analyzer and a blood biochemical analyzer,respectively.Serum antioxidant indexes and plasma hormone levels were measured using the biochemical kits.The gas chromatograph was applied to detect the fecal short chain fatty acids.Results Compared with the CG,the total feed intake(TFI)and average daily feed intake(ADFI)were significantly increased(P<0.01),and the urea content in regular milk tended to increase(P=0.095)in the EG.The serum malondialdehyde(MDA)contents were decreased on day 90 of gestation and the day of farrowing(P<0.01),and the serum contents of total antioxidant capacity(T-AOC)tended to increase on day 17 of lactation(P=0.099)compared with the CG.Compared with the CG,the serum triglyceride(TG)concentrations in the EG tended to increase on day 90 of gestation(P=0.062),and the content of serum total protein(TP)and albumin(ALB)reduced on day 17 of lactation(P<0.01).Compared with the CG,plasm D-lactic acid content was decreased(P<0.05),and the plasma prostaglandin(PG)level tended to increase(P=0.088)in the EG on the day of farrowing and day 17 of lactation.Compared with the CG,fecal isobutyric acid concentration in the EG significantly decreased on the day of farrowing(P<0.05).Conclusion Adding 250-500 mg/kg silymarin to diets from the late gestation to the end of lactation could improve reproductive and lactation performance of sows via the regulation of nutrient metabolism and serum antioxidant.
文摘In field and laboratory conditions the reproductive potential (survival at different stages of development) of the Colorado potato beetle has been measured, the dependence of the parameters of insects fertility on varietal features of the feed has been investigated, the food activity of the representatives of insects from four areas of the Southern Urals has been measured, the intensity and time of hypersensitivity reactions on potato leaves has been defined. In laboratory experiments, the level of activity of hydrolytic enzymes in insects and the level of activity of these enzymes inhibitors in the leaves of three potato varieties differing in their resistance to the Colorado potato beetle have been determined. The results show that the insects-representatives of different samples have different food activity in relation to different potato varieties. High mortality rates were revealed at feeding with leaves of potato of the Bashkir variety characterized by a high level of hydrolases inhibitors and relatively rapid development of necrotic reactions after the appearance of eggs laying on the leaves. We suppose that the neerogenetic barrier appearing in the form of necrosis is the major cause of the fetal mortality of insects. The level of the content of inhibitors inactivating larvae digestive enzymes affects the survival of insects at postembryonic stages. The speed of the necrosis emergence, the level of activity of digestive enzymes inhibitors in potato can be considered as criteria for the selection of breeding material for resistance to the Colorado potato beetle.
基金Project(2008ZX07421-002) supported by the Key National Science and Technology Project of ChinaProject(50638020) supported by the National Natural Science Foundation of China
文摘The effectiveness of a magnetic ion exchange resin (MIEX) for the treatment of Hongze Lake water in China was evaluated, The kinetics of natural organic matter (NOM) removal at various MIEX doses and contact time, multiple-loading experiments, impacts of MIEX prior to coagulation on coagulant demands and the effectiveness of combination of MIEX, pre-chlorination and coagulation were investigated. Kinetic experimental results show that more than 80% UV254 and 67% dissolved organic carbon (DOC) from raw water can be removed by the use of MIEX alone. 94% sulfate, 69% nitrate and 98% bromide removals are obtained after the first use of MIEX in multiple-loading experiments. It is suggested that MIEX can be loaded up to 1 250 bed volume (BV, volume ratio of tested water to resin) or more without saturation when regarding organics removal as a target. MIEX can remove organics to a greater extend than coagulation and lower the coagulant demand when combining with coagulation. Chlorination experimental results show that MIEX can remove 57% chlorine demand and 77% trihalomethane formation potential (THMFP) for raw water. Pre-chlorination followed by MIEX and coagulation can give additional organic and THMFP removals. The results suggest that MIEX provides a new method to solve thc problem algae reproduction.
基金Supported by the State Key Laboratory of Freshwater Ecology and Biotechnology of China and Shanghai Fisheries University (Grant No. 200015).
文摘Hybrid tilapia weighing 7.71 g were reared in seawater at 24.0-29.0℃ for 8 weeks. The controls were fed to satiation twice a day throughout the experiment, whereas treatment groups were fed at 0.5%, 1.5% or 3.0% body weight per day for 4 weeks, and then to satiation for the remainder of the experiment. During the first 4-week period, there was a curvilinear relationship between growth rate and ration size. Fish fed 0.5% and 1.5% rations displayed compensatory growth response of 2 weeks duration during realimentation. The weight-adjusted growth rate of fish fed at 3% ration was not significantly different from that of the controls by the end of the experiment, when none of the treatment groups had caught up in body weight with the controls. Hyperphagia was observed for the first 2 weeks of realimenatation in fish previously fed at 3% ration, but persisted for the whole realimentation period in groups previously fed at 0.5% and 1.5% rations. None of the feed restricted groups showed improved digestibility, feed efficiency, or protein and energy retention efficiency.
基金supponed by National Natural Science Foundation of China(No.30270809).
文摘The classification and inheritance of rice starch RVA profiles were studied by testing RVA profiles of F2 clonally propagated population and some varieties, including japonica, indica, and glutinous types. All the RVA profiles of accessions could be divided into six kinds based on the cluster analysis, that is A, B, C, D, E and F. Feature profile of sticky variety was type A. The profiles of indica varieties could be presented as B, C, D, E and F types and that of japonica varieties fell into D, E and F types.RVA profiles of the rice were mainly affected by apparent amylose content (AAC), but the difference of RVA profiles could also be detected in the varieties with similar AAC. The close relationship between RVA profile indices and sensory of low or middle AAC varieties suggested that the RVA profiles can be used as indirect index to evaluate eating and cooking quality. In four hybrid combinations, the component indices of RVA profiles of F1 were between those of its parents except peak viscosity and pasting temperature. Also, in F2 clonally propagated population, all the components of the RVA profiles showed continuous segregation,suggesting that all of them were controlled by a series of minor genes, although Wx gene may play an important role in determining the RVA profiles. These results may provide some new information useful for rice quality breeding program.
基金supported by the National Science Foundation IOB-0641750
文摘The use of multisensory cues to locate mates can increase an organism's success by acting as a back-up plan when one system fails, by providing additional information to the receiver, and by increasing their ability to detect mates using senses that have different ranges in a variable aquatic environment. In this contribution we review the sensory cues that male horseshoe crabs Lirnulus polyphemus are known to use when locating mates and then provide new data that shed light on this subject. Dur- ing the breeding season, females migrate into shore during high tides to spawn. Males attach to females as they approach the beach or are attracted to pairs already spawning. Vision is well established as an important cue in attracting males. Although chemoreception is well known in other marine arthropods, and horseshoe crabs have the anatomy available, there are few studies on chemical cues in this species. Experiments are presented here that provide evidence for chemical cue use. We show that the attraction, and retention, of attached and satellite males to actively spawning females and mating pairs involves multimodal cues
基金supported by Environment and Conservation Fund, Hong Kong (Project number: ECF 2009/29)
文摘Studying gonadal development of annual cycle can reveal the process of gametogenesis and reproductive period, and evaluate fertility and source utilization of a species. Host sea anemones are conspicuous members of tropical and subtropical reef ecosystems, but little is known about its biology including reproductive seasonality. Here we reported a one-year study on the gametogenesis and reproduction of host sea anemone(Entacmaea quadricolor) inhabiting Hong Kong waters. E. quadricolor tissues were sampled in 12 occasions from 5 m and 15 m depths of water, respectively. Histological sectioning of the tissues showed that E. quadricolor was dioecious, and populational ratio of female to male was 1:1.6. The gonadal development was asynchronous within an annual cycle, which included proliferating, growing, maturing, spawning, and resting stages. The spawning occurred between August and October when surface seawater temperature reached the annual maximum(28℃), suggesting that temperature is an important factor modulating the gonadal development and mature of E. quadricolor.
基金funded by the Natural Science Foundation of China (41106099)CAS Scientific Project of Innovation and Interdisciplinary, the Ministry of Science and Technology Project Foundation (2014FY210600)+1 种基金Yantai Science and Technology Bureau (2011061)the Natural Science Foundation of Shandong Province (ZR 2009EQ006)
文摘Seagrass decline caused by the macroalgae blooms is becoming a common phenomenon throughout temperate and tropical regions. We summarized the incidence of macroalgae blooms throughout the world and their impact on seagrass beds by direct and indirect ways. The competition for living space and using resources is the most direct effect on seagrass beds when macroalgae are blooming in an aquatic ecosystem. The consequence of macroalgae blooms(e.g., light reduction, hypoxia, and decomposition) can produce significant indirect effects on seagrass beds. Light reduction by the macroalgae can decrease the growth and recruitment of seagrasses, and decomposition of macroalgae mats can increase the anoxic and eutrophic conditions, which can further constrict the seagrass growth. Meanwhile, the presence of seagrass shoots can provide substrate for the macroalgae blooms. Controlling nutrient sources from the land to coastal waters is a general efficient way for coastal management. Researching into the synergistical effect of climate change and anthropognic nutrient loads on the interaction between searsasses and macroalgae can provide valuable information to decrease the negative effects of macroalgae blooms on seagrasses in eutrophic areas.
文摘Breeding and mass scale larval rearing of clownfish Amphiprion percula is very limited in brackishwater. We designed an indoor program of A. percula culture in brackishwater with a salinity of 24±1, during which the impacts of feed type, water temperature, and light intensity, on the efficiency of its reproduction, were revealed. The fish were accommodated along with sea anemones in fibre glass tanks to determine the influence of brooder diet on breeding efficiency. Higher reproductive efficiency [number of eggs laid (276±22.3 eggs)] was observed when fish were fed live Acetes sp. rather than clam (204±16.4 eggs), trash fish (155±12 eggs) and formulated feed (110±10 eggs). The spawning rate was increased during September and October (water temperature, 28.74±0.55℃) on average of 2.4 spawning per month; and low spawning rate was in January (water temperature, 24.55±0.45℃) on average of I spawning per month. Among three light intensities (100, 500, and 900 1x) set to evaluate larval survival rate, larvae showed the highest survival rate (65.5%) at 900 lx. The breeding method specifically in brackishwater developed in the present study is a new approach, will help the people from the regions of estuary and backwater to enhance their livelihood and it will lead to reduce the exploitation from the wild habitat.
文摘Cherry regeneration via somatic embryogenesis is a powerful tool to breeding. In this way, the embryogenic capacity of Prunus incisa specie has been tested from leaves under different interactions of picloram concentrations and darkness exposures. Induction culture was achieved on MS medium supplemented with picloram concentrations at 0.5, 1 and 1.5 mg.L1 and submitted to 10, 20, 30 and 40 days of darkness. The best rate of embryogenic leaves was obtained with the interaction of 30 days darkness exposure* 1 mg.L^-1 picloram. According to their age, leaves were differently reacted to somatic embryogenesis; indeed, the 2nd expanded leaf from the apex was the most embryogenic one. Concerning the effect of additional auxin to picloram (1 mg·L^-1), IAA at 0.1 mg·L^-1 and IBA at 0.1 mg·L^-1 gave significantly higher induction rates than all other concentrations, but regenerating somatic embryos showed some teratological abnormalities probably due to seconda;y embryogenesis. At the opposite, NAA at 0.5 mg·L^-1 didn't improve embryogenic rate but affected positively embryo development. Furthermore, embryogenesis preferentially took place on the basal part of leaf. Satisfactory rates of somatic embryogenesis are obtained but further improvement remains possible.