| In view of the new understanding of an important position of Class Collembola(springtails) in the soil ecosystem and its toxicological ecology research value, thesystematic study to springtail biology become one particularly important content in mordenbiology. This thesis studied in detail the adult laborary cultue, the living embryo cultureand the embryonic development process of four representative species of springtails inadvantage springtail groups of North China as experimental material. In these works somespringtail biological research bottlenecks considered for a long time were explored andsolved. The main work is as follows:Firstly, all experimental materials of the springtails were collected from the Yimengregion, Taishan and Luxi (west Shandong Province) area along the Grand Canal. The livingspringtails selected by sieve soil samples were cultured in lab, and12species of springtailshave been reproducted successfully. Four representative dominant species were used inembryonic development researches in this paper:1) the species Ceratophyselladuplicispinosa, belong to Order Poduromorpha, Family Hypogastruridae;2) the speciesHomidia similis, belong to Order Entomobryomorpha, Family Entomobryoidea, SubfamilyEntomobryidae;3) the species Orchesellides sp. nov., belong to Order Entomobryomorpha,Family Entomobryoidea, Subfamily Orchesellinae and4) the species Vertagopus sp.,belong to Order Entomobryomorpha, Family Isotomidae.The experiments show that the Subfamily Entomobryidae species have strongjumping ability, so they require a large culture bottle to provid big enough living space; theSubfamily Orchesellinae species have activity in general, but requirements moredemanding ambient temperature and air humidity, suitable for cultivation at roomtemperature for22±2°C, humidity of not less than70%under the conditions; The FamilyHypogastruridae species is not more demand to living space becaues of small individual,but they have so strong jumping ability that easy escape from their culture bottle, thereforetheir culture bottle should be better in the tightness.Secondly, a suitable for the majority of springtails living embryo culture and livingobservation under a microscope produce method,“the method of coverslipes building space on slide” was created in the thesis work. Using the method, not only the livingembryo can be cultured for long time in slide, but also the living embryo can bephotographed and recorded under microscope at any time. In addition, the technology andmethod is also suitable for many other small arthropods and other small to miniatureanimals.Third, the breeding，embryonic development and hatching process of the four speciesof springtails were observed, photographed and recorded using a stereo microscope(Olympus SZX12) and system microscope (Olympus BX51). The collembolans entireembryonic development can be divided into7stages i.e. early spawning, cleavage stage,blastocyst stage, gastrula stage, tissue differentiation stage, hatching stage and hatchinglarval stage. The experimental results show the following aspects:(1) The all springtails species has the following characteristics:1) the isolecithal eggs;2) complete and equal cleavage,3) invagination gastrulation;4) the morphological changeprocess of embryo in the egg shell is similar.(2) Four groups of the springtails have some obviously different in some aspects:1)the isolecithal eggs of the species Ceratophysella duplicispinosa have sharp edges of thelarger nuclei, the diameter of the nucleus is about105μm, oocyte diameter ofapproximately3/5. Other representative species did not be found this phenomenon.2) Ofthe four species of early spawning, not only the only the C. duplicispinosa eggs has largenucleus, but the nuclear gradually disappear after a few minutes, until the first eggcrack notbe found again; on the contrary, in the other3species the early spawning cytoplasm isevenly distributed, but after a few hours, the different types of multicore phenomenon wereobserved under a microscope.3) The duration of the various stages of the four speciesembryo development is differences, Family Hypogastruridae has the longest duration in theearly embryo development, equivalent to other species spent nearly twice of relative timeas much or even more; but its blastocyst stage development time is extremely short, spendrelatively time is about other species1/2or even less. In the other three species, the time ofeach stage is similar.In addition, there are some complex differences between the three kinds of springtails, Homidia similis, Vertagopus sp. and Orchesellides sp. nov., belong to OrderEntomobryomorpha.In summary, the researches results show that, in the embryo development of OrderPoduromorpha and Order Entomobryomorpha, all springtails have some common featuresincluding the similar isolecithal eggs, complete and equal cleavage, invaginationgastrulation, and the morphological change process of embryo in the egg shell and so on.These features significantly differ from the Insecta (s. str.), which is consistent with theresults of the recent studies about some morphological and molecular biology researches.But there are some different between the four groups of this study. Authors believe thatthese differences contribute to new understanding of the relationship between the varioustypes of group springtails. Of course, as the study of time limit, with more research, will itis possible to draw firm conclusions. |
PDF Full Text Request