The present study investigated effects of environmental relevant concentrations of 4-nonylphenol (0.05 to 0.08 to 0.1 mg/l) on the reproduction and embryonic developmental stages of catfish (Clarias gariepinus). To determine the effect of 4-nonylphenol on reproduction; catfish were exposed to three concentrations of 4-nonylphenol in a flow-through-system during spawning period (some for one week and other for two weeks). At an estimated 4-nonylphenol concentration the fertilization rate and hatching rate were significantly decreased with 4-nonylphenol concentrations increasing while the incubation period, the mortality rate and malformed embryos ratio were increased. Also, the development of embryos and larvae was affected by 4-nonylphenol in terms of morphological changes and histopathological alterations.

The Tunisian desert harbors an important socioeconomic pastoral species including the Calligonum. It has an important ecological and ethological role. An important biodiversity is to be signaled in Tunisia. Variability within the Calligonum Tunisian genus has not been a thorough scientific study. Therefore, the morphological and anatomical characteristics may play an important role in the analysis of this variability. The present study is an attempt to gather information and analyze morphological and anatomical natural diversity within the Tunisian Calligonum genus to distinguish the three species (C. azel Maire C. arich Le Houérou and C. comosum L’Herit.) cited in the Tunisian flora. The present report deals with three species of Calligonum of (Polygonaceae) collected from Tunisian desert using morphological and anatomical traits. 10 plants for each species were used in our study. The degree of similarity among the three species has also been studied through these traits. The gotten dendrogram showed two groups: The first is composed of C. comosum and C. azel with a similarity of 29% in the morphological an anatomical trait. The second is formed by C. arich with a likeness of 15% with the first group.