Interpretations of determination and canalisation of stamen development in a tomato mutant

Abstract

Floral buds of different sizes of the single-gene recessive mutant stamenless-2 (sl₂/sl₂) of tomato were treated with gibberellic acid (GA₃) and the development of staminal features in each bud was followed. The results show that the application of GA₃ to buds with stamen primordia at the early stages of initiation (up to 0.1 mm in length) induced the formation of normal-looking stamens. However, with a progressive increase in stamen size, less and less of the normal stamen features were produced following the GA₃ treatment. Ultimately, buds with stamen primordia 0.8 mm long or longer failed to respond to GA₃ and produced all the mutant characteristics. These results are discussed in terms of Waddington's concept of “determination” and “canalisation” of development.