Abstract
The purpose of the experiments reported here was to study the process of bulb formation at the depth of 6-10cm underground and the effects of temperature on cotyledon growth of A. rosenbachianum REGEL in wooden boxes, glass root-boxes and petridishes respectively.
Observations indicate that the emerged epigeal cotyledon keeps the seedling green for about two months without sprouting leaves.
The hypogeal cotyledon, especially its part 2-4mm from the base grows geotropically and rapidly for about thirty days.
When the hypogeal cotyledon reaches to 6-10cm underground, the primary-root appears at the base of the cotyledon without lateral roots and it does not elongate over 3-5cm.
At the growing point the first and second leaves differentiate succesively and develop into protective-and storage-leaf respectively, and at their base a small bulb develops at the depth of 6-10cm underground.
The cotyledon develops normally at 5-25°C and grows more rapidly at 20-25°C than 5°C.
Also, the mode of penetration of the growing point and desirable methods of seeding were discussed.
