1. Determination was carried out for distribution of electric potential on the surface of a typical hypogeal embryo, Phaseolus angularis, and distribution curves of the potential were obtained for various stages of germination up to 6 days after sowing. 2. A valley of potential curve appears in the elongating region of epicotyl of 2-to 6-day-old embryo, and the hypothesis for the epigeal plant given in the former paper2), viz. the hypothesis that distribution of elongation velocity along the elongation axis coincides with distribution of second spatial derivative of the potential with respect to the elongation axis, seems to be applicable to the epicotyl of Phaseolusangularis. 3. Cotyledon has a higher potential level than the elongating part of epicotyl and the potential gradient between cotyledon and epicotyl is steep in the earlier stages of germination, gradually decreasing in later stages.
Young pea stem sections were treated by 2, 4-dichloroanisole (DCA), malefic hydrazide (MH), coumarin, p-chloromercuribenzoate (PCMB), monoiodoacetic acid and 2, 4-dinitrophenol (DNP), in combination with IAA or without it. Promotion and inhibition of water absorption due to various concentrations of those substances were amazingly paralleled by pectin methylesterase (PME) activity of the homogenate of the treated tissue. Compared with other substances, DNP inhibited water absorption relatively more severely than PME activity. The effects of substances on the PME activity in the case of tissue treatment were not due to their direct effects on the enzyme preparation. A hypothesis is proposed that activated PME increases extensibility of walls of growing cells, and consequently their water absorption.
The sporeling pattern of Makinoa crispata is described and discussed. The first cell division takes place after the rupture of the exospore; the second or third division is longitudinal and the sporeling develops into several-celled primaryplant whose apical cell has two cutting faces; the apical cell forms the meristematic apical region which becomes 4-7 cells thick at middle; the first rhizoid develops normally after the 6-celled stage and is characteristically purplish brown as that of the adult thallus; the oil-bodies in the earlier stage of development are similar to those of adult thallus except for their size, This pattern may be named as Makinoa-type. The relationship between the Makinoaceae and other related families is discussed from the view point of the sporeling pattern.
1. The pollen grain of Paris hexaphylla Chamisso. does not germinate on the sugar agar medium. By adding aspartic and glutamic acids, histidine or cysteine to the control medium, the pollen grain is, however, enabled to germinate readily. 2. Although the pollen grain of Orya sativa L. can germinate to a certain extent on the control medium, the germination was markedly stimulated when arginine, valine or alanine was added to the medium. 3. The kinds of amino acids which accelerate the germination of the pollen grain of Paris hexaphylla when they were added to the culture medium, were found to be present in the pollen grain itself and in the pistil of this plant. A similar relation was found to be true in the case of Oryza sativa L.
1. The cell walls of the full matured cotton seed hairs were chemically purified and dispersed by the ultrasonics. The structure of the cellulose fibrillar system of the cell walls treated with the above procedure, has deen observed under the light microscope and electron microscope. 2. The cellulose fibrillar system is formed by the unit of cellulose fibrillar bundle One cotton fiber has many segments constructed by 2 or 4 collaterally situated cellulose fibrillar bundles having axially parallel orientation. 3. Upper and lower ends of the bundles in each segment represent plumous rami fication (Fig. 4 A, B, Fig. 5) which can be easily distinguished from a rope like middle portion (Figs. 2A, B and C). 4. The cellulose fibril has a diameter of 100Å-250Å. The fibrillar bundle has a diameter of ca. 4μ. Full length of the bundle is 100μ-1200μ. 5. One pair of the fibrillar bundles in each segment situated in lateral symmetry or dorsiventral symmetry, but in the case of 2 pairs, the 2 lateral pairs are situated in dorsivental symmetry (Figs. 1A, B and C).