| The effect of the culture temperature before and after cutting operation to regeneration of Hydra magnipapillata is significant. We have focused on the change of the activities of three kinds of antioxidant enzymes such as SOD, CAT and GSH-PX, the expression of peroxidase of hydra basal disc and the distribution of nematocysts during the hydra regeneration. The results show that:1. The culture temperature before and after cutting operation has a significant influence on regeneration of Hydra magnipapillata. The anterior and posterior segments of hydra by cutting which were cultured at different temperature gradients (temperature range: 9℃-30℃, each temperature gradient intervals 3℃) were cultured at different temperature gradients (temperature range: 9℃-30℃, each temperature gradient intervals 3℃). The regeneration process of the hydra polyps was observed after cutting. When at the same culture temperature before cutting operation, the time of regenerating complete hydra had the decreasing trend with the increasing culture temperature (9℃excluded) after cutting operation; When at the same culture temperature after cutting operation, the time of regenerating complete hydra still showed the decreasing trend with the increasing culture temperature (27℃and 30℃excluded) before cutting operation. When the hydra that cultured at high temperature 27℃and 30℃were cut, the hydra segments were cultured at the low temperature 9℃, which did not regenerate complete hydra. In addition, it appeared the phenomenon of abnormal development such as some hydra having more heads or basal discs. The hydra were cultured at the low temperature 9℃, 12℃and 15℃, then the cut anterior segments were cultured at 9℃-30℃, and resultly we observed a small number of hydra having more basal discs. The hydra were cultured at the low temperature 9℃, then the cut anterior segments were cultured at 27℃and 30℃, a small number of hydra had double heads.2. The expression levels of three kinds of antioxidant enzymes such as SOD,CAT and GSH-PX had significant change during the regeneration of Hydra magnipapillata. Hydra could accomplish head and foot regeneration within 56h at 20℃. The activities of SOD and CAT of hydra had the decreasing trend during head regeneration, GSH-PX activity firstly decreased and then increased. During the foot regeneration, the activity of SOD and GSH-PX had the decreasing trend, the activity of CAT had the increasing trend. Based on the remarkable difference of the activities of three kinds of antioxidant enzymes of Hydra magnipapillata between during head regeneration and during foot regeneration, it is clearly indicated that there may be some different mechanisms between hydra head regeneration and hydra foot regeneration.3. The peroxidase had expressed in the ectoderm of the margin area of basal disc, but not in the ectoderm of the central area (aboral pore) of basal disc during the foot regeneration of Hydra magnipapillata. The cytochemical staining method based on substrate ABTS was used to reveal the expression of the peroxidase of hydra basal disc, a small quantity of peroxidase began to express at basal disc after 20 hours of basal disc regeneration, then the peroxidase expression increased gradually, and tended to be invariable after 52 hours of basal disc regeneration. The increasing tendency of peroxidase expression during basal disc regeneration directly reveals the process of cell differentiation, and the peroxidase may play a certain role in maintaining the structural integrity of the basal disc.4. Each cnidoblast of hydra contains a specific organelle that is nematocyst. There were four kinds of nematocysts such as stenotele, holotrichous isorhiza, desmoneme and atrichous isorhiza in Hydra magnipapillata. The distribution of nematocysts in the different body regions of hydra had significant difference. The type and quantity of nematocysts had obvious change in the new regenerated head and the posterior segment during the head regeneration of hydra. During the head regeneration, the quantity of four kinds of nematocysts increased gradually in the new regenerated head, the quantity of stenoteles and holotrichous isorhizas did not change significantly in the posterior segment of hydra, but the quantity of desmonemes and atrichous isorhizas had the decreasing tread. The increasing nematocysts not only generated from interstitial cells differentiating, but also might come from transferred nematocysts of the posterior segment of hydra.
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