An attempt is made to calculate the absolute amount of daily photosynthesis in submerged plants at various depths and under different weather conditions on the basis of photosynthesis-light intesity curve and surface and subsurface light intensity records, with reference to transparency and light extinction coefficient of water. Theoretical daily gross photosynthesis-depth curves well correspond to the vertical distribution of daily photosynthesis in natural communities of submerged macrophyte and that of phytoplankton in stagnation period of lakes and ocean. A logical interpretation is given to the empirically known correlation between compensation depth for aquatic green plants and transparency of water. Daily compensation depth for different seasons and weather conditions are in inverse proportion to the corresponding light extinction coefficient of water, or in proportion to the value of transparency. The monthly mean of daily compensation depth/transparency ratio for Elodea occidentalis in Lake Biwa is 2.0, 2.4 and 1.4 in January, April and July-August respectively. The ratio for Chlorella ellipsoidea ranges from 0.9 (rainy day, January) to 2.5 (fine day, July-August). It is noted that compensation depth is usually about twice as large as transparency. Considering that physiological activities of shoots, especially photosynthesis, are less active in basal parts of submerged macrophyte community than in upper parts, it is concluded that the daily compensation depth for the whole community might be considerably smaller than the values here calculated for apical parts of shoots.
The two strains of callus, one strain BD that forms “embryo” and the other strains BND that shows no differentiation, were isolated from the callus of the common origin after two years of culturing. The BD strain formed chlorophyll, while BND, which is a translucent callus with a good rate of multiplication, showed no chlorophyll formation. The KA, a different strain, showed no differentiation of organs on the basic culture medium. Using these three strains, the effect of IAA and kinetin on organ formation was experimented. The BD differentiates “embryos” on the basic medium, its formation being controlled by IAA. In the KA, bud differentiation is induced under white fluorescent light in the range of suitable combinations of IAA and kinetin. The embryogenesis of BD is similar to that of the embryo in an ovule. In KA, development of spherical colonies precedes adventive bud formation. In this case, a base for buds is formed which then grows into adventive buds. In BND, cultured cells are variable in nature, so the “embryo” forming portion is maintained by selection. The conditions for inducement of buds differ with types, but even in the same type they differ with strains or callus age, so that generalizations on the bud inducement process are now difficult. The previous papers1, 2) reported studies on Tradescantia and Paeonia calli and revealed that the calli were generally mixoploidal cell colonies which were lacking cytological uniformity. Hitherto the studies of induccing certain organs from colonies have been attempted for the purpose to observe whether or not uniformity of calli is gained to form an entire plant. In the present paper the effects of auxin and kinetin on the embryogenesis of the three strains of calli derived from the two forms of Solanum will be reported.
The changes of peroxidase- and catalase-activity were investigated in each organ of bean seed embryo at the germination stage. The peroxidase-activity was strongest in radicule. In plumule the activity was comparatively strong, while the activity in hypocotyl and epicotyl remained at a certain level through the germination stage. In cotyledon and plumule, the catalase activities were the strongest. In axial organs it was shown to have a certain value. In radicule the activity was the weakest. The so-called enzymic organ-specificity was clearly shown in the feature that peroxidase was much in root and catalase was present in a large amount in leaf. The change of the protohemin-content in each organ through the germination period was studied. The hemin-content in cotyledon was kept unchanged at a certain level throughout the germination period. The value of the level was higher than that found in other germinating organs. Each germinating organ of the seedling showed a steady (almost linear) increase in the hemin-content with the growth. This fact suggested that hemin was newly produced, functioning and acting in the growing plant tissues. Especially the plumule, despite it was small in size, contained hemin of a high concentration and exhibited the character of active organ at the germination-stage. Each hemin amount of peroxidase and catalase was estimated from their activities, and the fractions of these hemin in the total hemin were compared and discussed.
The spectro-reflectance curves of red rose petals (Fig. 1) of cultivars, Happiness, Karl Herbst and Radar, were compared with the spectro-transmittance curves of the pigment solutions containing 25-450γ/ml of cyanin at pH 2.0-3.5 (Fig. 2). When cyanin in higher concentrations was applied, its transmittance curve came near to the reflectance one. The transmittance curve of cyanin solution saturated with rutin was more similar to the reflectance curve. To make the better comparison between two kinds of curve, several per cent. of reflectance must be deducted from the total reflectance measured, taking the surface reflection of red petals into account (Yasuda, 1964)10).
Chromosomes in root nodules and the morphology of root nodules in nineteen species of seven tribes in leguminous plants were observed. The nodules can be grouped into two types from the morphological characteristics: A) spherical type (the meristematic regions occur at several positions surrounding the bacteroidal zone); B) apical type (the meristematic region is localized at the apical portion). It was found that each of the taxonomical tribes showed either one of the two types of nodules. The nodules, on the other hand, can be divided into two groups through the ploidy of chromosome number: A) diploid nodules (with the diploid meristematic regions); B) tetraploid nodules (with a tetraploid meristematic region). In the respective taxonomical tribes, either one of the two nodule groups was observed. There appears to be a definite relationship between the morphology and the ploidy of the nodules, i.e. the nodules of spherical type are of mostly tetraploid. Species of Hedysareae and Phaseoleae were of the diploid-spherical type and those of Cassieae, Trifolieae, Galegeae and Vicieae were of the tetraploid-apical type. It is presumed that the ploidy of the root nodule is an inherited characteristic of leguminous plants.