3.1. Stomatal frequency and size
The stoma of Pothos has a form that are common to the seed
plants [7], and by viewing the cross section of a leaf, It turned
out that stomata were distributed evenly on the outer skin surface
(Fig. 2). The stomatal frequency and their size were investigated on
four places of Pothos, namely the blade surface, its reverse side, the
petiole, and the stem. It is known that the stomatal frequency of
a plant will change with its living environments [8], and that the
hormone to control the number of stomata is discovered [9]. Stomata
distributed most frequently on the reverse side of a blade, and
least frequently on the petiole. The common stomatal frequency of
herbaceous shade plants is 50–100 in 1 mm2, but when compared
to it,they were fewer than the mean on most ofthe reverse sides on
Pothos blades [8]. Although we found some different sizes, Pothos
stomata were mostly within the range of common stomatal size
(about 25–30 m) in herbaceous shade plants