Studies on bulb formation of garlic plants. I.

Abstract

The present study has been conducted to investigate the periodic development of clove and inflorescence of garlic plant and the effects of environmental conditions on the initiation and development of them.1. Initiation of inflorescence in garlic plant begun about early and middle April when the temperature reached at about 10°C, under natural conditions. Following to the initiation of inflorescence, one to five lateral buds were produced in a group on the axel of several foliage-leaves just below the inflorescence. The outermost, second and third leaf of lateral buds grew up to protective-, storage-, and sprout-leaf respectively, in consequent of thinning or thickening of them. Thereafter, the lateral buds grew up to side-bulbs, named cloves.2. In a small plant having no inflorescence, no lateral buds initiated on axel, while the terminal bud formed the storage-leaf and grew up to the central-bulb, so-called“round”. Accordingly, it seemed that the central-bulb formation shows the failure of inflorescence initiation.3. Storage-leaf and inflorescence formed in spring and developed under long-day and warm conditions. The plant which was never exposed to low temperature failed to form storage-leaf and inflorescence even under long-day conditions.Photoperiod did not relate to the initiation of inflorescence and lateral bud.4. Planting of small bulbs, late planting and defoliation resulted in the inhibition of inflorescence initiation, and consequently the number of bolting plant decreased. It seemed that inflorescence in garlic plant initiate after a considerable duration of vegetable growth.5. There are some strains which show different phenomenon in bolting character.It seemed that in the non-bolting strains, flower stalk did not elongate after the initiation of inflorescence and top-sets grew up to side-bulbs.6. The short-day treatment after April 5 caused an acceleration of growth of leaf-blade in lateral buds, and cloves were not formed. Storage-leaf was formed under long-day condition, the formation did not depend on the attached position of leaf, but on the conditions of metamorphosing.