Blue light response of stomata with starch-containing ( Vicia faba) and starch-deficient ( Allium cepa) guard cells under background illumination with red light

Abstract

Two plant species, Vicia faba with starch-containing guard cells and Allium cepa with starch-deficient guard cells, were compared for stomatal response to blue light in order to clarify whether hydrolysis of starch in guard cells is involved in opening of stomata by blue light. The rates of transpiration of Vicia and Allium leaves increased upon illumination with strong red light and very weak blue light remarkably enhanced the rates of these species when applied simultaneously with the red light. The same blue light applied without the background was much less effective for opening of stomata. No significant difference was found between these two species in the rates of transpiration induced by blue light with background red light. It is concluded that blue light effect is not brought about via starch hydrolysis and is observable only when photosynthetic mechanism is operating with red light.