Abstract
1. In the chloroplast of Selaginella Savatieri the green spirals were confirmed as in the case of S. uncinata. The amoeboid type of the chloroplast-division was detected besides the three types of division, i. e. the ordinary division-type, the longitudinal division-type and the lateral division-type.
In the meristem of S. Savatieri the cell which has only one chloroplast divides after the nuclear division and the thus-formed two daughter cells contain one chloroplast, respectively. Some of these cells which contain one chloroplast remain always to have one chloroplast after successive divisions and remain as the meristematic cells but some of them become to have many chloroplasts which are induced by means of division from the original one.
2. In the shade or the dark place, the structure of the chloroplast which has showed the homogeneous structure changes into the spiral one and the green spirals can be observed clearly. In the chloroplast of S. uncinata the green spirals swell and become to be obscure when treated with 2/5M aqueous solution of NH4Cl. In the chloroplsts of some plants which have showed homogeneous structure the green spirals become clear when treated with the aqueous solution of acid, alkali or some fixatives. In the chloroplast which shows the green spirals the spiral structure becomes more evidently when left in the shade or dark place.
3. In the cells of Chara sp. which show the active protoplasm-streaming, the chloroplast, sometimes, changes from the homogeneous structure into the spiral one or vice versa.
4. In the chloroplasts of various plants including Pteridophytic ones it is thought the green spirals always exist, but in some cases, the chloroplast shows the homogeneous structure owing to the swelling of the green spirals. In this case, however, the homogeneous structure changes into the spiral one when treated with the reagent which acts to shrink. Therefore, the green spirals are visible or invisible according to its state of swelling or shrinkage.
5. The green spirals are observed in most of the plants, to say nothing of the Pteridophytic ones. The so-called grana is thought to be the optical section, the swollen points, the tightly coiled portion of the green spiral or the products of the photosynthesis. Sometimes, in nature, the grana-structure is observed and it changes reversibly into the homogeneous one through the green-spiral-structure (c. f. Yuasa 1949).
The reticulate, the fibrous, the granulous or the homogeneous structure which has been advocated by the various authors can be explained by the spiral one.
The membraneous structure which has been observed by means of the electron- microscope is though to be induced by the splitting of the green spirals as the polytene threads.
