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.