Recently the nutritive and sanitary value of seaweeds began to be rated higher. Above
aIl the production of Undaria pinnatifida is increasing rapidly，and so it is to be desired that we go deep into the study of its edible value and make full use of it. But so far little investigation has been done into the relations between the tissue of Undaria pinnatifida and its microingredients. And so We took up the variations and fading of color of the
pigments，attaching importance to the tissue of Undaria pinnatifida，and made a study of
the rise and fall of carotenoid pigments in connection with chlorophyll. Now We'll make
a report of a little knowledge We have got.
Undaria pinnatifida used for the observation were fresh one，salted one，and dry one
whose growing districts were clear. We oberved them through a standard optical microscope，a fluorescence microscope，and a scanning electron microscope.
By making a few alterations to the barium hydroxide method，We calculated β-Carotene
through the spectrophotometer of Shimazu spectronic 20A type，and the self-registering spectrophotometer of Hitachi 124 type. the results were as foIlows.
(1) The epidermal cells of the thallus of fresh Undaria pinnatifida were nearly discoid，between four and five microns, and consisted of tinier single-layered ceIls than the ones of the plants on the ground. The spaces among the cells were pretty wide. And in the epidermal cells denser chlorophyll was found through the microscope than in the cortex and the medullary layer.
(2) It was confirmed that β-Carotene was contained within Undaria pinnatifida，and We
observed some variations by processing and storing.