Abstract
In the leaves of wheat plant, most of the mesophyll cells which are called the arm-palisade cells have several lateral protuberances developed at right angles to the leaf surface. In this experiment, the mesophyll structure of the wheat leaves, grown under the shades of natural daylight, were observed and following results are obtained. 1) In the leaf blades developing in the shade, the number of protuberances in a cell decrease and the cells having no protuberance increase at the base of the leaf blades inserted at lower levels of the shoot. Diameter of protuberance is larger and its length is shorter in the shade. 2) As far as the cells having the same number of protuberances are concerned, the cells in the shade are longer in length and shorter in width than those in natural daylight. 3) The ratio of the cell surface to the cell volume (S/V) and the number of cells per unit leaf area are decreased in the shade. Therefore, the total cell surface per unit leaf area is smaller in the shade than that in natural daylight. 4) At the base of the leaf blade, the above-mentioned structural changes of the mesophyll are more remarkable than those of the other portions. Accordingly, it may be concluded that the leaves developing in the shade are more resembled to the lower leaves having a structure of shade leaves.
