Y. Juliarni,"goto et al., TUBERIZATION IN APIOS (APIOS-AMERICANA MEDIKUS) .1. DEVELOPMENTAL MORPHOLOGY OF TUBER, Nippon Sakumotsu Gakkai Kiji, 66(3), 1997, pp. 466-471
The formation process of rhizome to tuber in Apios americana Medikus (
apios, groundnut) was investigated. The rhizome is a stem, which is sh
own by its morphological and anatomical structures. It consists of sev
eral nodes and internodes, stipule-like structures, scale-like leaves
with axillary buds, and a hook-shaped tip. Several roots were develope
d on the rhizome just at the basal side of each node. Tubers bf apios
formed with the swelling of each internode of the rhizome, and they de
veloped at basal internodes through internodes near the rhizome tip. I
n general, the first tuber developed at the Ist through the 4th intern
odes of rhizome. Three developmental processes could be recognized dur
ing tuberization in each internode: (I) tuber initiation, (II) extensi
on of swelling areas, and (III) dominant enlargement of tuber. Tuberiz
ation took place at 8 weeks after planting. The swelling of internodes
initiated at the basal side of the axillary bud of the node, extended
basipetally and enlarged laterally. The swelling areas of the interno
des coincided with the location of root development which occupied 20
to 50% of the length of the internode. Thus, a whole internode did not
always swell. In a field, however, a whole internode or several succe
ssive short internodes were sometimes tuberized.