Sucrose Transport into, and Unloading from, the Seed Coat of Empty Ovules of Pisum sativum over Time-Spans Greater than Three Hours

Abstract

Summary This paper discusses whether assimilate transport into seed coats of surgically modified ovules deteriorates over time-spans greater than about 3 h. In experiments with fruits of pea ( Pisum sativum L.), several hours before the start of a pulse-labelling procedure, two empty ovules were prepared in each fruit. Subsequently, after a time interval of several hours, two other empty ovules were prepared in each fruit. Immediately after this procedure, [ 14 C]sucrose was fed to the leaf subtending the fruiting node. During a pulse-chase period (80-360 min), transport of 14 C into ovules operated several hours before the start of a pulse-labelling procedure was only slightly reduced, in comparison with transport of 14 C into ovules operated directly before the start of a pulse-labelling procedure. Data on the release of 14 C-solutes from the seed coat also supported the view that, with respect to sucrose transport into developing ovules, surgically modified ovules can function almost normally over time-spans of at least 6-8 h.