ABSTRACT
In this study, urease content was screened in 20 species of three tribes of Tiliaceae and four tribes of Malvaceae. Data showed some correlations at the tribal level in both Tiliaceae and Malvaceae. In Tiliaceae, the highest urease level was recorded in Triumfetta rhomboidea [Tribe Triumfetteae], while the lowest values were recorded in Grewia species [Tribe Grewieae] and Corchorus species [Tribe Enteleae] gave intermediate urease levels. In Malvaceae, Pavonia triloba [Tribe Ureneae] contained the highest urease level [243 units] among the wild species of the family, while Abutilon pannosum [Tribe Abutileae] gave the lowest [1.07 units] activity. In this family, the highest specific activity recorded in cultivated specific were 8.7 and 7.1 units mg-1 protein for Gossypium barbadense cv. Giza 51 [Tribe Hibisceae] and Hibiscus sabdariffa [Tribe Hibisceae], respectively, while it was 5.3 units mg-1 protein in the wild species [Pavonia triloba]. Difference in urease level in the seeds of the studied plants proved its value for a better understanding of the affinities among the taxa of Tiliaceae and Malvaceae and could be applied for chemical taxonomy of the flowering plants