Nitrate-Induced Morphological Anomalies in the Tadpoles of Nyctibatrachus major and Fejervarya limnocharis (Anura: Ranidae)

摘要

The present study examined the effects of nitrate on the tadpoles of 2 ranid frogs (Nyctibatrachus major and Fejervarya limnocharis) studied under laboratory conditions. Tadpoles of these species were exposed to ecologically relevant concentrations of nitrates (0, 100, 2500, and 5000 μg NO3-N l-1). Upon exposure tadpoles of N. major showed protruded mouth, swollen body and head, paralysis, lateral and vertical swimming, restlessness, and wriggling movement. Tadpoles of F. limnocharis showed swollen body and head, bent tail, paralysis, restlessness, depigmentation, and intestinal hemorrhage. In both species, abnormalities increased with the increase in nitrate concentration. However, compared to F. limnocharis, tadpoles of N. major were more sensitive as they died before completing their larval tenure. Based on the results of this experiment, it is hypothesized that tadpoles of N. major are more sensitive and vulnerable to nitrate contamination.