Preliminary Study On Early Development And Salinity Tolerance In Inimicus Japonicas

Biological adaptation to the environment is the most common phenomenon in thenature,through its own morphology, morphology habits and physiological functionadapting to environment.However,stress is a basic characteristic of biological lifeactivities,efensive of maintain biology steady when stimulated,a basic of biologicaladaptation and its survival and development.In teleost,except pituitary-hypothalamussystem,also has its unique neuroendocrine system-caudal neurosecretory system.Thereare many study on caudal neurosecretory system,but in presently about the developmentprocess have reported little.Inimicus japonicus,warm-temperate,offshore and benthicfish,in presently,there are many researches on reproductive biology and artificialbreeding,the other aspects of the research are relatively few.By Inimicus japonicus as the research object,researching the early development ofmorphological change,skeletal development,caudal neurosecretory system anddifferent development stages of the salinity tolerance.The results were as follows:1、 The observation that carried on system to the growth growth characteristic ofInimicus japonicus earlier period life history stage described growth growthcharacteristic of its embryo growth, Larval and young fry. The fertilizied egg istransparent and no oil ball. Take off a film to hatch from eggs after40-60hs in the watertemperature19-23℃. Develop time and temperature to present negative relatedrelation. The beginning hatches all of the larval fishes to grow a3.9mms, the age opensmouth on the3rd, the yolk disappears take place on the5th. Henceforth, the tail fin,dorsal fin, anal fin and pelvic fin continuously develop. The age appears tail fin fin onthe10th, on the13th age tail Suo up raise, the age is basic for it to form on the15th. Theage models on the20th. on the25th, body color and temperament take place to change.Each fin of age on the35th the growth Heng settle, external appearance and lifetemperament with become fish homology.2、 Through the cartilage-bone double dyeing method to observe Inimicusjaponicus early development process (newly hatched larva-35days of age) vertebralcolumn and appendages of the bone development process. The results showed that thegrowth of the vertebral column by11to13days of bow and pulse bow successively development as a starting point, after20days,centrum, medullary spines, pulses pineswere formed, then after35days,it completed ossification,development sequence andossification are back once. The development of appendages bone sequence is shoulderbelt, hypural, radial fin of pectoral fin, belts, dorsal fin of pectoral fin, anal fin ofpectoral fin, epural bone.After3days, the cleithrum and pectoral fin of radial fin werebasically formed,11thdays cartilage of radial fin of pectoral fin were formed.Belt andventral fin appear later (18days), but rapidly development. Dorsal fin of pectoral finand anal fin of pectoral fin appeared in20days, the dorsal fin developed from centralbody. Spines support fin bone development from front to back, and anal fin developedfrom the body mid backward. The caudal fin with8days development fish bone of thedevelopment of the tail as the starting point, after15days, caudal basic forming,fluctuation two leaves a fin bone formation, the article caudal divided into fluctuationtwo parts.32days caudal fins bone formed and completed preliminary ossification.Inimicus japonicus vertebral column and appendage bone early development and itsearly function between adaptability have a close relationship.3、On the normal histologic method to study the caudal neurosecretory system andearly development stage different individual day age of Inimicus japonicus,through thecontinuous slice,histological observation through H.E and Azure II-toluidine blue tostain adult and different development stages of caudal neurosecretory system,usingUⅠ/UⅡantiserum for immunohistochemical study on adult and different developmentstages of caudal neurosecretory system.The results showed that Dahlgren cell werelarge,basophilla,polymorphism of the nuclear, immunoreaction onUⅠ/UⅡantiserum.Dahlgren cell mainly distributed in the tail end of spinal cord,bothsides in the central tube into the symmetric distribution.The complete system of caudalneurosecretory appeared relatively late in time,Dahlgren cell change With thedevelopment of the individual.4、 Compared salinity tolerance among different development stages of Inimicusjaponicus larva stage.The Result Indicated that Salinity tolerance have difference indifferent development stages,different development stages of Salinity tolerance rangeis not completely the same,mainly difference occured in Salinity5,after opening larvaethe ability to adapt Salinity5is significantly enhanced.The most optimum salinity rangeof newly hatched larvae is20-25, It is10-15，the most optimum salinity range ofopening before the larvae，opening after the larvae、Yolk disappears before larvae、Yolkdisappears after the larvae。 After larvae the adaptability of the salinity is relativelyweak.Different development stages of Inimicus japonicus in different salinity conditions of the SAI value and the mean survival times were positively correlated.