Intraspecific competition for weight growth was analysed in constituent Abies trees within a 20-year-old A. Mariesii and A. Veitchii mixed stand of Forest Unit V on Mt. Shimagare. 1. Annual dry matter increments in needles, branches, trunk and roots of each of trees, which were classified into the dominant, codominant, intermediate and suppressed, were estimated by the mathematical analyses of tree measures. Annual net production, the sum total of these increments per tree, increased with rise in gradation of the tree weight class. Also the relative productivity (net production/tree weight), the net assimilation rate and the relative growth rate indicated the same trend. 2. The inner and outer factors concerned with the dry matter production were discussed. The somewhat high proportion of needles for the total dry weight and the high light intensity received by needles were responsible for the high productivity in the dominant class. 3. Annual gross production per tree was calculated in each tree weight class by combining photosynthetic activity and light factor received by each canopy, with correction by seasonal temperature changes. Annual respiration loss was also calculated. 4. The difference between the annual gross production and the annual respiration loss gave the net production per tree. This value was in accord with the annual net production determined by the analyses of tree measures, in each class. The accordance may prove the soundness of the calculations. 5. The suppressed tree made relatively small gross production under weak illumination, but high respiration loss comparing with its dry weight. So the growth rate of the suppressed became very low. The reverse was seen in the dominant. Such difference in matter production between the dominant and other tree classes should cause marked growth difference with the lapse of time.
Effect of natural twilight on photoperiodic responses of Pharbitis seedlings was examined. 1) The inductive dark process proceeds from the time at which luminosity is about 100-200lux. 2) The inductive dark process is inhibited by morning twilight of 0-1lux. Generally, it may be said that the biological day length for flowering of this plant begins at the beginning of civil twilight in the morning and ends at the time of astronomical sunset. On cloudy days, however, the biological day length becomes shorter than that on clear days by some 30 minutes and becomes nearly equal to the astronomical day length.
The zoosporophyte of Ulva pertusa Kjellm. collected near Hakodate is reported here to have been proved cytologically to undergo meiosis in zoospore formation as previous authors have already reported in other species of Ulva and Enteromorpha. Haploid chromosome number was established to be 13. A centrosome-like body was present at each pole of the spindle in the metaphase of meiosis. Each sporangium produced 16 quadriflagellate zoospores.
The occurrence of gibberellin-like substances in extracts of shoots, roots and immature grains of rice and maize, and shoots and immature grains of wheat was examined by the rice seedling method after chromatography on paper with ammoniacal iso-propanol. Gibberellin-like substances were present in amounts approximately equivalent to 0.1-0.5μg. of gibberellin A3 per 100g. fresh weight in shoots and roots, and 0.5-1.5μg. in immature grains. The necessity for the use of intact green plants for bioassay of hormones, which are responsible for elongation in shoots, is discussed.
1. IAA and PAA added as growth substances in culture medium have respectively almost the same effect as the standard medium on the morphological differentiation of gametophyte of a fern, Dryopteris erythrosora. 2. No diffusible auxin is detected in all stages of gametophyte development examined. 3. Ether extractable auxin is detected only in later stages of gametophyte development when the meristematic region acts vigorously. In other stages, from spore to young gametophyte, ether extractable auxin is not detectable. 4. By the chromatographic analysis of bound auxin it is revealed that in the one-dimensional growth bound auxin is present as IAA and three growth promoting substances (Y1, Y2, Y3) and in the two-dimensional growth as IAA, two growth promoting substances (Y1, Y2) and one growth inhibiting substance (Y3'). 5. From these results it may be concluded that changes of bound auxin are correlated solely to the two-dimensional differentiation.
1) The effect of diphenylamine (DPA) added to the culture media upon the chromogenesis of Penicillium islandicum Sopp., NRRL 1175, was investigated, and the results are shown in Table 2. At lower concentrations below 1×10-4M, DPA did not show any significant effect on the mycelial growth and the formation of erythroskyrin was delayed nearly a week in comparison with the control. 2) At the concentration of 2.5×10-4M DPA, the growth of the fungus as well as the formation of anthraquinone pigments was apparently reduced, but any of the component anthraquinones was not lost. However, the formation of erythroskyrin was completely abolished in this case. 3) Since DPA has been shown to be specific inhibitor for the carotenogenesis in general (Goodwin et al.), erythroskyrin seems to be a carotenoid-like substance. 4) As regards the unknown pigments described in the preceding paper1), pig-0.8 was identified as emodin (cf. Fig. 1) by paper chromatography (Tab. 1), and pig-C has been made plausible by Shibata et al. 2, 3) to have the structure of 4, 5, 7, 4', 5', 7'-hexahydroxy-2, 2'-dihydroxymethly-bis (1-1')-anthraquinone (cf. the structural formula in Fig. 1). 5) In the light of these and previous results1) of our experiments, biosynthetic interrelationship of the pigments concerned was discussed. In consequence, it was shown that Shibata's hypothetial biosynthetic scheme (Fig. 1) is consistent in its essential feature with our experimental findings, but not in subsidiary pathway involving chrysophanol, flavoskyrin and emodin. This awaits further studies.