Abstract
The present study was conducted to clarify the differences of the aperture of the stomata and their diurnal movement of a leaf due to its position on the stem. In the fully-expanded leaves, the higher the position of a leaf on the stem, the wider was its stomatal aperture. The stomatal aperture of an expanding leaf was smaller compared with those of the adjacent lower fully-expanded leaf. During elongation stage of the internode the aperture of the most upper fully-expanded leaf was not so wide as in the adjacent lower one. The diurnal movements of the stomata of the leaves on a stem were different from each other depending on their position on the stem. Especially in the sunshiny day the stomatal aperture of the upper ful1y-expanded leaf did not decrease so quickly as those of the lower one in the afternoon, after reaching the maximurn per day, and this phenomenon could be more distinctly recognized after the heading stage. The results that the aperture of the stomata and their diurnal movement in the leaves were different from each other owing to their position on the stem were discussed in connection with the vascular, especially xylem, in the leaf sheath or the internode, the leaf age and the root age.
