絲瓜不定根內之側根源之發育

Initiation of the Lateral Root in the Adventitious Aerial Root of Luffa Cylindrica

The initiation of lateral roots from both old-and young-parts of the aerial root of Luffa cylindrica (Linn.) Roem. is reported. The dormancy of the lateral root initial in the young aerial root is also discussed. The lateral root from the older part is initiated in the region near the vascular cambium in the ray, whereas in the younger part it originates from a group of pericyclic cells located opposite the protoxylem strand. Though the lateral root primordia are organized very early in a regular pattern in the young part, no lateral roots become emergent until they are dipped in water, or penetrate into the earth. If the air is not wet enough. the aerial root stops growing and its tip becomes hypertrophied and the pericyele-cortex complex retains a strong meristematic potential instead of a promeristem. The pericycle-cortex complex gives rise to numerous lateral roots soon after dipping in water.