(1) Inoculations were made with urediospores of Puccinia Agropyri ELL. et Ev. on the leaves of Hordeum sativum PERSOON, Triticum vulgare VILL., Secale cereale L., Avena sativa L., A. fatua L., Bromus unioloides H. B. et K., B. japonicus THUNB., Poa annua L., P. acroleuca STEUD., Anthox anthum odoratum L. and Briza maxima L. In all cases the germtube enters hte stoma as freely as on its own host plant (Agropyron semicostatum NEES) and the infection hyphae invariably send out haustoria into the host cells. The wall of the guard cell in contact with appressoria generally undergoes certain changes in staining reaction and finally the cell dies. It seems probable that the death of the guard cell is caused by certain toxic products resulting from the disorganization of the fungus. (2) On the seedlings of barley and rye the rust may develop successfully and form uredia several days after inoculation. The urediospores thus formed may infect these plants generation after generation. In the field it is proved that these plants are readily infected when the diseased plant of Agropyron is placed near them. Careful examination of the infected leaf shows that the mesophyll cells in the infected area lose turgidity and their chloroplasts become smaller and less in number. The haust ria formed in these cells appear to become inactive, while those in the overlying epidermal cells and in the cells of parenchyma sheath give a vigorous appearance, maintaining the function for a period longer than in the former. (3) The inoculations on wheat, oat, Avena fatua, and Bromus japonicus bring about the necrotic areas. Here both the haustoria and the invaded cells are found disorganized. It shows that the fungus is able after infection to develop to a certain stage, obtaining the nutritive substance through the agency of the short-lived haustoria. The haustoria formed in an early stage of the fungus development seem to die soon, while those formed subsequently can grow larger and maintain their function a little longer. The lately formed haustoria are surrounded by the sheath. In the host-cells involving these haustoria the disorganization takes place later than in those involving the unsheathed haustoria. (4) Anthoxanthum odoratum, Poa annua and P. acroleuca show apparently no sign of infection. Microscopically however it is found that the fungous hypha forms usually three haustoria in succession, which soon disorganize together wi h their host cell.
It is pointed out that the “Transpirational Ratio” of LINFORD (4) is not appricable to discuss the transpiration history of the wilting plants. The. writers observed the transpiring power of excised soy beans inserted into the staled liquid media of Fusarium niveum. It is found that the dicrease of the transpiring power of the wilting plants is parallel to the progress of the wilt phenomenon.
1. Comparative morphological studies of a group of Uromyces on the following 13 Japanese species of Lespedeza and one of Microlespedeza, which has been treated as a collective species, Uromyces Lespedezae-procumbentis (SCHW.) CURTIS, have been conducted. They are: Lespedeza bicolor TURCZ. (& var. japonica NAKAI), L. Buergeri MIQ., L. cuneata G. DON., L. cyrtobotrya MIQ., L. cystoides NAKAI var. inschanica NAKAI, L. homoloba NAKAI, L. Maximowiczii C. K. SCHN., L. nipponica NAKAI, L. pilosa SIEB. et ZUCC., L. pubescens HAYATA, L. retusa NAKAI, L. Thunbergii NAKAI, L. tomentosa SIEB. and Microlespedeza striata MAK. From the results of the studies, the fungi on those different plants were divided morphologically into the following two distinct species. 1) Uromyces Lespedezae procumbentis (SCHW.) CURTIS on the above 13 species of Lespedeza. Among these host plants, the following 7 species; Lespedeza cystoides var. inschanica, L. homoloba, L. Maximowiczii, L. nipponica, L. retusa, L. Thunbergii and L. tomentosa are new additions to the hosts of the present species. 2) Uromyces Itoanus HIRATSUKA, f. (nov. spec.) on Microlespedeza striata MAK. This fungus also occurs on Microlespedeza stipulacea MAK. in Manchuria. 2. In order to determine the parasitism of Uromyces Lespedezae-procumbentis (SCHW.) CURTIS and U. Itoanus HIRATSUKA, f., inoculation experiments were undertaken, and the results of the experiments are summarized as follows:- 1) A number of inoculation experiments with aecidiospores or uredospores of Uromyces Lespedezae-procumbentis on Lespedeza bicolor var. japonica and L. Buergeri were made on Lespedeza bicolor, L. bicolor var. japonica, L. Buergeri, L. cuneata, L. pilosa, L. Thunbergii, L. virgata and Microlespedeza striata, and positive results were obtained on Lespedeza; L. bicolor, L. bicolor var. japonica, L. Buergeri and L. Thunbergii. 2) A number of inoculation experiments with uredospores of Uromyces Itoanus on Microlespedeza striata were made on Lespedeza bicolor, L. bicolor var. japonica, L. Buergeri, L. cuneata, L. pilosa, L. Thunbergii, L. virgata Microlespedeza striata, and positive results were secured on the controlling plant, Microlespedeza striata, while on all species of Lespedeza inoculations were unsuccessful.
1. Thee Ascochyta fungi parasitic on the pea have been studied by the writer. 2. The diseases caused by Ascochyla Pisi, A. Pinodes (Mycosphaerella Pinodes) and A. Pinodella are designated “blight”, “brown spot” and “foot rot” respectively. 3. The brown spot (A. Pinodes) is the most destructive of the three diseases in Japan. 4. On the leaf Ascochyta Pisi produces light-tan marginate spots which are distinguishable from purplish-brown irregular lesions caused by the other Ascochyta. 5. A. Pinodella and A. Pinodes form black lesions on the foot, and A. Pinodella rots the foot severely, while A. Pisi does not infect it. 6. The ascigerous stage has been found in culture and on the host only in A. Pinodes.
The present paper deals with the results of the author's experiments on the biological characters of pseudo-myceliolyse of Ophiobolus Miyabeanus ITO et KURIBAYASHI (=Helmlnthosporium Oryzae BREDA de HAAN) with special reference to the effect of temperature and constituent of media on the occurrence of the phenomenon, and the rate of enlargement, the time required of incipient and final stage of pseudo-myceliolyse. The temperature has a profound effect on the occurrence of pseudomyceliolyse. The optimum temperature for pseudo-myceliolyse on potato sucrose agar lies at 23 to 28°C, especially at about 24°C. No pseudo-myceliolyse occurred in cultures grown at 16°C, or temperature lower than this and at 37°C, or above than this. Pseudo-myceliolyse occurred frequently on such various liquid or agar media as potato sucrose, rice straw decoction, synthetic media with asparagine, and peptone, corn meal and apricot decoction. No peudo-myceliolyse occurred on MIYOSHI's and SAITO's onion soy ager. Pseudo-myceliolyse increased its area at the rate of 0.496 to 5.106, average 3, 511mm spuare per minute at 23°C. In a certain part of the area of pseudo-myceliolyse developed at the rate of 0.083 to 0.5, average 0.291μ per minute at 17 to 20°C. The incipient stage of psedo-myceliolyse appeared in 54 to 74, average 64 hours at 32°C and 49 to 69, average 59 hours at 23°C after inoculation. The final stage of pseudo-myceliolyse was 72 to 95 hours from cultures were started, and was 20 hours in average from its incipient stage. The pseudo-myceliolyse could not, therefore, been recognized unless a detailed and continuous observation has been made.