Abstract
Three dwarf types of rice plant, Ebisu (AAbb), Daikoku (aaBB), and Kodaikoku (aabb), differing in the intensity of green colour of leaves, were compared with the normal type Akage (AABB) as to the chlorophyll content. The leaves of those dwarf genotypes contain about 130-150% of the amount of chlorophylls in the normal when the chlorophyll is determined on the basis of the same leaf area, while the less differences were found when it is estimated on the basis of the same weight of fresh leaves. This result was also supported by the comparative studies on the relation between the leaf area and leaf weight in the different types concerned.
Anatomical observations showed that the assimilatory tissues in the leaves of dwarf types are generally about twice as thick as that of normals in the region of the small vascular bundles. In the middle part between two small vascular bundles, however, they are, on account of the abnormal development of the motor cells, rather thinner in dwarfs than in normals.
The palisade tissue of dwarf types, as compared with that of normals, consists of larger cells, but no differences were found as to the size of cells in spongy tissue.
The number of assimilatory cell layers in dwarf types is comparatively large, while the differences in the density of cells in these layers were not proved.
It is concluded that the deep green colour in dwarf types of rice is mainly caused by the large size of palisade cells and the increase in number of the assimilatory cell layers.
