Study Of Gonad Development And Growths Of Turbinaria Peltata And Galaxea Astreata

In recent years, the environment deterioration and globle warning caused theecosystem of coral reefs degenerated rapidly. The study on reproductive biology and theimpact of environment in coral reefs were had important singnificance for the problem.This paper studies the Turbinaria peltata and Galaxea astreata during the development ofsexual reproduction gametes, the sexual reproduction, larval settlement, early coral larvasurvival, and the survival and growth of coral nubbins in different orientation, obtained thefollowing results:1) Study of Reproductive Ecology and fecundity of Turbinaria peltata and Galaxeaastreata.Sexual reproduction and gonad development of two scleractinian species, T. peltataand G. astreata, were studied in the Xu wen coral reef. Based on the physiologicalstructure characteristics, the results show that T. peltata was dioecious and fertilizedexternally after released gametes, G. astreata was simultaneous hermaphrodites andfertilized externally after released gametes. Gamete development of two scleractinianspecies was classified for four time phase. The oocytes of T. peltata occurred between theend of October and begin of November and the oocytes developed over a6-7month period;the testis occurred in the mid to late February and the testis developed over a3-4monthperiod. The oocytes of G. astreata occurred in the mid November and begin of Decemberand the oocytes developed over a5-6month period; the testis occurred in March. Asoogenesis progressed of scleractinian species, we observed a gradual reduction in thenucleus to cytoplasm ratio due to the steady synthesis of yolk. Measurements are reportedof each scleractinian species have difference in both histological sections and decalcifiedmaterial. There was a positive correlation between lipid content of corals and gonadmaturation, lipid content of two scleractinian species have significant difference.2) The reproduction, larval settlement and early survival of Turbinaria peltata andGalaxea astreata in preliminary study.T. peltata coral is observed experimentally in vitro fertilization of gametes dischargeddioecious type, G. astreata is discharged androgynous type of coral gametes in vitrofertilization. Under laboratory conditions using different light intensities to change theorientation of coral larvae attached to study these two coral larval settlement, the law of survival of the early to assess the impact of adult coral distribution process generated. Theexperimental results showed that: the strength of the light was no significant difference inthe T. peltata larvae attached to the white tile in different orientations, while the G.astreata larvae attached there is a huge influence, especially attached to the lowest rate inthe downward orientation shading; two coral larvae under different lighting conditions arevertically attached to the white tile relatively high rates more. The reason in the earlystages of the experiment coral larvae died just simple individual disappearance and death,with the extension of time to farming in the later stages of the experiment, the coral larvaemortality gradually increased, mainly due to sediment algae breeding period.3) The survival and growth of Turbinaria peltata and Galaxea astreata coral nubbinsin different orientation.Collected at Xu wen coral reef sanctuary T. peltata and G. astreata nubbins,respectively, in situ and laboratory breeding waters for60days to observe the survival andgrowth characteristics. The results can be seen from the results: T. peltata nubbins in theoverall survival rate was higher than in the waters situ breeding laboratory breeding coralreef tank nubbins survival, and survival is the opposite nubbins G. astreata; Shield T.peltata nubbins in situ sea and laboratory culture is in the upward vertical orientation andthe highest survival, and thin in a different orientation G. astreata nubbins maximumsurvival difference is small. Two coral nubbins in the laboratory breeding of slow earlygrowth, mid-late breeding faster relative growth, the maximum average growth rates tendto appear in the late breeding; T. peltata nubbins average growth in natural lighting andshading conditions rate difference was not significant, while the G. astreata nubbins on thecontrary, under natural light conditions, the average growth rate of coral coral nubbins wassignificantly higher than the average growth rate in blackout conditions. Under differentlight conditions the same specifications T. peltata nubbins average growth rate in the sameperiod a smaller difference (P>0.05), while the average growth rate G. astreata nubbinssignificant difference (P <0.05). Proliferation in the number of breeding laboratory T.peltata and G. astreata nubbins bearing bodies are with the extension of breeding time andgradually increase; same specifications under the same lighting conditions in two differentorientations coral nubbins bearing body number does not exist significant proliferationdifference (P>0.05), T. peltata number of nubbins bearing body proliferation of differentspecifications for the same period in the late breeding was significantly higher (P <0.05),and G. astreata bearing body number of nubbins proliferation during each breedingdifferences were not significant (P>0.05).