In the description of plants some observations from the standpoint of the lifeform were not uncertain. We discussed some of ambiguous types of life-forms in the previous paper (Report II, 1956). After Raunkiaer, “Geophytes include land plants whose surviving buds or shoot-apices are borne on subterranean shoots at a distance from the surface of the ground” (1934, p. 64). On the contrary, “all hemicryptophytes have their surviving buds or shoot-apices situated in the soil-surface” (p. 41), and “the buds do not come above the surface of the ground” (p. 40). The difference between the expressions “at a distance from the soil-surface” and “in the soil-surface” is sometimes very nice, especially in shallow geophytes. We measured as many individuals of doubtful species as possible at different habitats (Figs. 1-10, Tables 1-3). That explains the matter there are variable species such as Desmodium racemosum and Vicia unijuga, and little-variable ones such as Ligularia tussilaginea. In the former a geophyte in a statistical meaning is sometimes like a hemicryptophyte or a chamaephyte as shown in Table 2. And the type of the life-form of species forming a dead centre (Figs. 1-2) is too apt to be misjudged in a season when the clonal connection breaks. The position characteristic of the surviving bud of variable species (Table 2) is considered to some extent as an indicator criterion, but in other plants the value as an indicator is little.
1. The photoperiodic responses of a short-day plant, Salvinia natans, were studied by supplying with the organic acids of citric acid cycle. The acids used were citric, succinic, fumaric and malic acids, added to the culture solution only during the dark period. 2. The developments of the sporocarps were inhibited by the citric acid of all Nov.-Dec. 1959 Bot. Mag. Tokyo, Vol. 72, Nos. 857-858 465 the concentrations tested, while in succinic, fumaric or malic acid of lower concentrations their developments were more or less accelerated, especially by the succinic acid. 3. The inhibiting effect of citric acid on the photoperiodic induction was not found when the other acids were also used at the same time. These facts seem to suggest that the effect of citric acid on a process of the photoperiodic induction was antagonistic with that of the others, though all the acids used were available as the substitutes of carbohydrate required for the development of the sporocarps. 4. The malonic acid combined with the acids other than citric acid made some decreases in the photoinductive effect, whereas it was notably increased when the former acid was used alone. In citric acid, however, no such decreases were observed. 5. These facts seem to indicate that a relative quantity of the organic acids in the plants may be an important factor for an alternation from the vegetative to the reproductive phase.
1. The present work was carried out to investigate experimentally if the germination percentage and the pollen tube growth are different among various densities of pollen grains put on sucrose agar media. 2. These pollen grains of the following plant species Camellia sinensis, C. japonica, Iris pseudacorus, Lathyrus odoratus and Oenothera Lamarkiana were used for this purpose. 3. The greater the number of the grouping grains became the more the germination percentage and the tube growth increased. The difference of the tube growth was most conspicuous when a single isolated grain was compared with the two grains grouping set side by side. 4. A group consisting of five or six pollen grains secures the best growth of the pollen tube on agar media, whereas more grouping grains are required to gain the best germination percentage. 5. It was discussed that certain substances might take part in the increment of germination percentage and the acceleration of pollen tube growth.