Studies on the tillering in genus Allium. VI

Abstract

In this paper, the mechanism and mode of the tillering of Chinese leek were studied using var. “Oba-Nira” under natural conditions. 1. The mechanism of the tillering of Chinese leek is similar to that of the welsh onion with the exception of the following single point mentioned in 2. 2. The 1st and 2nd leaves of the tiller are usually formed on the phyllotaxy plane of the mother plant, however the 3rd and subsequent leaves are not formed on this plane. Soon after the commencement of tillering bud formation, the phyllotaxy plane of the mother plant changes its direction unmethodically. Namely, while the phyllotaxy planes of tiller and mother plant are on the same plane at first, later they become separated from each other. 3. In a plant which has fully developed in tillerings, the tillers are arranged in a circle or elliptical group. In this case, there is no rule as to the arrangement of these tillers. 4. The indications of flower bud differentiation are quite similar to those of the welsh onion. The initial stages of involucre formation becomes discernible in middle June, and flower cluster development progresses rapidly until the flowers commence to bloom in early or middle August. Soon after the beginning of involucre formation, a new vegetative axillary bud is formed at the base of the primordium of the flower cluster stalk. This bud developes in parallel with the flower cluster and grows into a perfectly developed mature plant. 5. Under natural conditions, the first tiller of seedling appeared at the 6th or 7th node of the main plant, and the percentage of appearance at the 6th node was 71.4 and that at the 7 th node was 28.6. Most of the 2nd and subsequent tillers appeared at the 1st, 2nd or 3rd node after the preceding tiller had occurred, and the frequency of appearance at the 2nd node was the highest. 6. The average number of tillers coming from a seedling in a growing season was 23.6, and that of differentiated leaves was 150.5. 7. At times, the development of a tillering bud was so slow that the tiller appeared from the leaf sheath of preceding node too late to be normal. These abnormal tillerings were frequently observed in the late stage of the growing season. No examples of other types of abnormal tillerings were observed in Chinese leek.