The change in stomatal density of cereals under different environmental factors (2nd report).

Abstract

1) On the previous paper, we distinguished the following three types of crops, according to the stomatal density on the upper and lower surfaces of leaves : 2) Summer type : The stomatal density on the lower surface of the leaf is always higher than that on the upper. 3) Winter type : The stomatal density on the upper surface of the leaf is always higher than that on the lower. 4) Intermediate type : The stomatal density on the upper surface of the leaf is higher than that on the lower during the younger stage of life, and is lower in the later stage. 5) Among the environmental factors, light, humidity, soil moisture and others, light is most universally responded by stomata. Under the control of light, we observed the change in stomatal density of cereals and found out the following fact. 6) The relative number of stomata on lower to upper surface of the leaf is nearly 1.00, when grown in darkness, notwithstanding species and varieties of cereals. 7) It seems, from the facts shown above, the cereals have ability of producing the same number of stomata on both upper and lower surfaces of the leaf. Adaptation of this ability to the light conditions causes the distinction of the three types ; Summer, Winter and Intermediate types.