FREE AND CONJUGATED INDOLE-3-ACETIC-ACID IN DEVELOPING SEEDS OF SECHIUM EDULE SW

The occurrence and dynamics of free and bound IAA levels in single par ts of Sechium edule seeds at various stages of development were invest igated. The highest contribution to the whole seed pool is derived fro m bound IAA and especially from the IAA content of endosperm and tegum ents. In these tissues a peak in total and bound IAA can be observed c oinciding with the phase of rapid seed growth. In the embryo, total an d bound IAA levels show a continuous increment during development. On the contrary, the free IAA level, In al the tissues examined, remains at a constantly low level during the whole developmental process. The pattern of free and bound IAA of S. edule developing seeds is differen t from that observed in other species and is discussed in relation to the viviparity of this cucurbit.