1969 Volume 38 Issue 1 Pages 52-59
An investigation was made of the anatomical structure of the shoot apex in To-pe-tsai (Brassica chinensis L.). It is found that the young apex has one tunica layer, and the zonation is not evident. The tunica layer increace to the maximum of 4-5 when the apex becomes adult, and when tend to reproductive phase, the layer increase to 5-6, and then decrease rapidly to 3 before the 1st flower primordium is initiated.
1st to 4th leaf primordia are initiated at the 2nd layer of the peripheral zone by periclinal division, whereas 5th to the terminal leaf (bract) are initiated from the 3rd layer, and are also by periclinal division. The floral primordia are initiated from 4th layer constantly.
The upper internods elongation occure before the 1st floral primordium is initiated. The first symptom of the bolting can be observed as a cell elongation at the subapical region.
