A Distinction between Bolting and Flowering Effects on Senescence

Abstract

IT is well known that flowering and fruiting processes bring about the senescence of most annual species of plants. Molisch¹ interpreted this senescence as due to the mobilization of food materials into the fruits. His interpretation has been questioned by Leopold, Kamien and Janick², for staminate as well as unpollinated pistillate plants of spinach show senescence after flowering. Both staminate and pistillate spinach plants develop a large seed stalk with the commencement of reproductive development, and it may be that Molisch's interpretation could be made more correct by including the mobilization of food materials into the stalk as an explanation of the imposition of senescence. The application of gibberellin to spinach which has not experienced photoperiodic induction will result in the formation of a stalk without the further development of flowers, providing an opportunity for distinguishing between the effects of bolting and of flowering on senescence.