| This thesis deals with the embryonic development and the effects of differenttemperature and salinities on the metabolism rate (indicated by oxygen consumption rateand ammonia excretion rate) and the activities of two related enzymes in the first instarsof Tachypleus tridentatus. The main studying contents and results are as follows.1. The fertilized eggs were obtained through artificial fertilization, and incubated at28℃constant temperature. The development of embryos including first and secondinstars was observed and described from fertilization to hatching out. According to theexisted literatures and observation of the author, the development periods were classifiedinto 9 stages: cleavage stage, blastula stage, gastrula stage, inner egg envelope period,segmentation period, appearance of rudimental appendages period, histologicaldifferentiation period, rapid growth period and hatching out.2. The growth of the embryo and the postembryonic development was described.During the whole stages of embryonic development, the embryo growth in weight (W: g)was significantly correlated with the embryo growth in length (L1: mm), the growth inwidth (L2: mm) and the average diameter (D:mm) of embryo. The correlated equationswere W=0008L12.6327 (R2=0.9902, p＜0.01), W=0.0008L22.7664 (R2=0.9858, p＜0.01) andW= 0.0008D2.7328(R2=0.993, p＜0.01), respectively.3 The effects of two main physical factors, water temperature and salinity onmetabolism rate in the first instars of Tachypleus tridentatus were studied. Five gradientsof water temperature and salinity which were 18℃, 21℃, 24℃, 27℃,30℃and 15‰,25‰,35‰,45‰,55‰respectively, were set in the two experiments. It was showedthat both the oxygen consumption rate (OCR) and nitrogen excretion rate (NR) increasedwith water temperature, and the OCR and NR rised with salinities firstly before thesalinity reached 35‰, then decreased. Among the temperature treatments, there were asignificant increase in OCR (P＜0.05) in 24℃treatments. 27℃and 30℃treatments weresignificantly higher than other treatments(P＜0.05); 30℃group was significantly higherthan other treatments(P＜0.05)in NR. Among the salinity treatments, OCR in 15‰was very significantly lower than other treatments(P＜0.05); NR in 25‰,35‰and 45‰weresignificantly higher than those in 15‰and 55‰(P＜0.05).4. Alkaline phosphatase(AKP) and ATPase were two kinds of enzymes that wererelated to growth and development of animals. The results showed that in the range oftemperature 18℃-30℃, the total tendency of the activities of AKP and Na+,K+-ATPasewas ascendent. In the salinity treatments, the activities of AKP and Na+,K+-ATPaseascended at first, then decreased. Among the temperature treatments, the activities ofAKP had no significant difference(P＞0.05); but the activities of Na+,K+-ATPase of 18℃and 21℃were significantly lower than the other treatments, and that of 24℃wassignificantly lower than 27℃and 30℃. Among the salinity sets, the activities of larvaeAKP under 35‰seawater was significantly higher than the activities under 15‰and 55‰(p＜0.05), but were not significantly different from those in 25‰and 55‰seawater.The activities of Na+,K+-ATPase in 35‰seawater were significantly lower than thosein 25‰, 35‰and 45‰. Activities of AKP and ATPase could be viewed as the indicatorsassessing the physiological condition of Tachypleus tridentatus.
|
PDF Full Text Request