Abstract
Aldrovanda vesiculosa is an aquatic carnivorous plant, close to extinction world-wide. Its carnivorous leaves bear numerous ‘digestive’ glands, which are believed to secrete digestive enzymes. Development and secretion of protease, one of the main digestive enzymes was studied on in vitro propagated plants. Gelatin film was used to detect protease activity. No protease activity was found in leaf tissue or in liquid secreted before prey was actually trapped. However, 2 h after prey was caught strong activity was detected both in carnivorous leaves and the secreted liquid. Protease activity was also detected in several bands after Native PAGE in tissue extract and the secreted liquid 2 h after trapping and in the secreted liquid 6 h after trapping. The accompanying dynamic ultrastructural changes observed by TEM in digestive gland cells will be discussed in relation to the synthesis and secretion of the enzymes.
