黑斑侧褶蛙变态前后身体大小的变化 及对植物血凝素的反应模式

为了解不同发育阶段黑斑侧褶蛙（Pelophylax nigromaculatus）身体大小和对植物血凝素（Phytohemagglutinin-P，PHA-P）溶液的反应，在室温为（25±2）℃条件下，戈斯纳37、38～39、40～41、42～43、44～45和46期蝌蚪被取样，测定了体重、体长、尾长、体全长和重长比，以及注射PHA-P溶液前（0 h）和注射后3，6，9和12 h被注射部位皮肤组织的增厚程度的变化。不同发育阶段蝌蚪的体重无显著差异（P>0.05），体长、尾长和体全长均随发育进程推进而缩短（P<0.05），但重长比在登陆前后明显增大（P<0.05）。登陆前（37～43期）蝌蚪对PHA-P的反应的峰值出现于注射后3 h（P<0.05），登陆后（44～45期和46期）出现于注射后6 h（P<0.05），但不同发育阶段的最大PHA-P反应无明显的组间差异（P>0.05）。黑斑侧褶蛙登陆后尾部萎缩，重长比明显增加，这些特征有利于提高其对陆生环境的适应性，但对PHA-P的反应的峰值被延迟，这可能是造成蝌蚪登陆后存活率低的主要原因之一。

Variations of body size and response patterns to phytohemagglutinin-P before and after metamorphosis in dark-spotted frogs, Pelophylax nigromaculata

To explore the variations of body size and the responsiveness to phytohemagglutinin-P (PHA-P) solution from different developmental stages, under the conditions of (25±2) ^oC temperature, Gosner 37, 38-39, 40-41, 42-43, 44-45 and 46 tadpoles of dark-spotted frogs, Pelophylax nigromaculatus were sampled, and the body mass, body length, tail length, total body length, and ratio of body mass to total body length, as well as the increased skin tissue thickness of injected positions was measured prior to injection (0 h), and 3, 6, 9 and 12 h after PHA-P solution injection. The body mass did not show significant differences among different postembryonic stages (P>0.05). The body length, tail length, and total body length was significantly shortened with progressive developmental stages (P<0.05), but the ratio of body mass to total body length was greatly increased before and after landing (P<0.05). Before landing (37-43 stage tadpoles), the responsiveness to PHA-P peaked 3 h postinjection (P<0.05); After landing (44-46 stage tadpoles), it peaked 6 h postinjection (P<0.05), and no significant group differences were found for the maximal PHA-P responses among different developmental stages (P>0.05). The dark-spotted frogs display atrophied tail, and increased ratio of body mass to total body length after landing, which may enhance their adaptations for terrestrial environment conditions. However, the maximal PHA-P response is delayed, which can be suggested as one of main factors leading to lower survival probability for landing tadpoles.