1. The relation of temperature to the growth of the strain of Piricularia Oryzae used in this experiment was first tested by growing the mycelium on potato decoction agar containing 1% sucrose at different temperatures. The most vigorous growth of mycelium seemed to occur at about 28°C. At the temperatures of about 24°C., 20°C., 11°C. and 36°C., the growth of the present fungus decreased gradually in order. 2. At about 28°C., the most favorable temperature to the fungus, the mycelial growth was stimulated by adding CuSo4 to the agar medium in the concentrations between 1/400 and 1/6000mol. The maximum growth occurred in the concentration of 1/1000mol. In the case of the liquid medium the stimulating action of CuSo4 to the mycelial growth of the fungus was more or less recognized. It was, however, not so remarkable as in the case of the agar medium. 3. At the various temperatures, such as 20°C., 24°C. and 32°C., the same experiments were done. However, the stimulating action of CuSo4 to the mycelial growth was not recognized in any concentrations tested. At about 36°C. any conclusive results were neither obtained in the liquid nor on the agar medium. 4. At all the temperatures tested, the conidial formation was retarded in inverse proportion to the amount of CuSo4, when added in higher concentrations than 1/6000mol. On the culture media containing CuSo4 in higher concentrations than 1/400mol., it was almost unrecognizable. 5. The conidial formation tends to decrease gradually with the difference of temperature from the optimum for the mycelial growth. Such retardation was most remarkable at about 36°C. 6. On the culture media containing CuSo4 in higher concentrations than 1/600mol., the chlamydospores were formed at all the temperatures tested. The limitation for the chlamydospore-formation with regard to the concentration of CuSo4 tends to become lower in proportion to the difference of temperature from the optimum for the mycelial growth. Such tendency is quite contrary to that of the conidial formation 7. The development of the aerial mycelium was checked gradually owing to the increment of the concentration of CuSo4 and it was not observed in the concentration of 1/200mol. at any temperatures tested. 8. On the culture media containing CuSo4 in higher concentr tion than 1/6000mol., the color of the colony changed to gradually from grayish white to dark, and the degree of coloring increased remarkably in the concentration of 1/400-1/600mol. In the concentration of 1/200mol., the colony showed yellowish olive and soaked appearance. The hyphae became remarkably slenderer and more winding than those of the controls.
WEIR and HUBERT (31) have suggested that the teleutospores of Uredinopsis Pteridis DIET. et HOLW. seem to have the power of germinating as soon as they are ripe without hibernation, and the needles of Abies become infected during the late summer or fall, and the aecidia appear early in the next spring. According to the writer's investigations, however, the teleutospores. of Uredinopsis Pteridis on Pteridium aquilinum KUHN var. japonicum NAKAI collected in the vicinity of Sapporo were proved to germinate in spring after having overwintered and to infect Abies Mayriana MIYABE et KUDO, when the needles are still young. The peridermial stage developed in about a month after the inoculation. (Fig. 1.) The aecidiospores thus obtained from the infection experiments were proved to infect the Japanese bracken, on which uredospores similar in characters to those found in the field were produced. The peridermial stage of Uredinopsis. Pteridis in the Pacific States of North America, was identified by JACKSON with Peridermium pseudobalsameum ARTH. et KERN, which appears always on the second year needles of Abies grandis, nobilis and amabilis. The writer could not help entertaining a grave doubt on the assertion of WEIR, HUBERT and JACKSON as to the life-cycle of Uredinopsis Pteridis in Western America. The repeated infection experiments performed by the writer have invariably shown that the aecidial stage of the fungus is formed on the young leaves of Abies Mayriana in late spring accompanied by spermagonia having a flattened conoidal to lense-like shape of the type of Peridermium balsameum PECK (Fig. 4, 5, 7), the characters common to other species of Uredinopsis. Moreover, according to HUNTER, the spermagonia of Uredinopsis Pteridis (Peridermium pseudobalsameum ARTH. et KERN) have hemispherical, vertically elongated shape as shown in Fig. 6. The spermagonia and peridermia formed on Abies Mayriana by the inoculation of the sporidia of Uredinopsis Pteridis are fully described as follows: O. Spermagonia amphigenous, mostly hypophyllous, on discolored areas, minute, numerous, punctate, irregularly and closely aggregated or scattered, (Fig. 3) usually isolated, at times confluent, honey-yellow at first, becoming later reddish brown, subcuticular, lenticular to subconoidal in shape, (Fig., 4 5, 7) 66-132μ broad, 37-66μ high; spermatophores obclavate, septate spermatia oblong or oblong-ovate, 1.6-2.8μ broad, 4.5-6.7μ long. (Fig. 8) I. Peridermia amphigenous, mostly hypophyllous, arranged in two rows on pale yellowish areas, occupying a part or all of the leaf, cylindrical, (Fig. 2, 3) 1.0-7.5mm. high, 0.3-0.5mm. across; peridium colorless, rupturing at apex, cells slightly overlapping, rhombic to hexagonal, 11-22μ broad, 19-40μ long, inner wall coarsely verrucose, 3-7μ thick, outer thinner ca, 1μ, smooth. Aecidiospores globoid to ellipsoidal, 15-24μ broad, 18-30μ long, mostly 20×22μ; wall colorless, 1-2μ thick, rather densely verrucose except a side having almost smooth wall; contents colorless; germpores invisible. O and I on the current year needles of Abies Mayriana MIYABE et KUDO formed by the inoculation of the sporidia obtained by the germination of the teleutospores of Uredinopsis Pteridis DIET. et HOLW. on Pteridium aquilinum KUHN var. japonicum NAKAI collected at Sapporo and Nopporo in the Province Ishikari, and at Kaributo in the Province Iburi by the writer, and also at Nioji-yama in the Province Echigo by Miss Homma.
1. The present investigation was undertaken to determine the relationships, one to another, of three bacteria, namely Bact. Sesami, Bact. solanacearum and Bact. sesamicola; those having been recorded as the cause of sesame diseases. 2. To this end a thorough comparative study of the morphology, culturlal features and physiology was made with authentic cultures. 3. From the results, I am inclined to believe that Bact. Sesami is identical with Bact. sesamicola, distinguished from Bact. solanacearum. Therefore Bact. sesamicola is applied as a synonym of Bact. Sesami. 4. The characters of Bact. Sesami are revised as follows: Bacterium Sesami MALKOFF Syn. Ps. Sesami. MALKOFF Bact. sesamicola TAKIMOTO A slightly long rod occurring singly or in pairs; 1.2-3.8×0.6-0.8μ when stained; polar flagella 2 to 5; no spores nor capsules present; Gram's negative. On beef broth grows rapidly almost without pellicle; clears milk without coagulation; blues litmus milk; slightly browns potato media; liquefies gelatin promptly. On beef agar plate the colonies are circular, flat, striate, smooth or umbonate with entire margin, taking on white and oparescent luster. On beef agar stroke or stab the growth is filiform, white and translucent with butyrous consistency. Aerobic; no gas is formed in sugars media; methylenblue is reduced but not nitrates; no hydrogen sulphide nor indol is produced. Temperature for growth, maximum 35°., minimum 0°., optimum 30°., thermal death point about 49°.. Group number is Bact. 221, 2332433. Pathogenic on sesame leaves and stems causing dark brown spots; Type locality: Sadovo, Bulgaria. Distribution: Bulgaria, India, Japan, Korea.
1. The rice seeds or kernels internally infected by Piricularia Oryzae Br. et Cav. or Ophiobolus Miyabeanus Ito et Kuribayashi (Helminthosporium Oryzae Breda de Haan) show generally a visible discoloration which varies froma small spot or a streak to a large area involving the entire surface, sometimes a shriveling. 2. Absence of external signs of disease can not be recognized as the conclusive evidence for the fact that the seeds are quite free from internal infection, because the writer has proved the existence of some internal fungous parasites of the rice seeds of healthy appearance by means of the microscopical examination as well as the isolating experiment. 3. The salt water selection (1. 1 sp. gr.), a method of selection by means of soaking seeds in a salt solution, seems to be unapplicable to the selection of healthy rice-seeds. 4. According to the results of inoculation experiments, Piricularia Oryzae and Ophiobolus Miyabeanus seem to have a power to infect the seeds at any time before and after the flowering period of rice. 5. Some parasitic fungi internal of rice seeds, such as Piricularia Oryzae and Ophiobolus Miyabeanus, cause the first occurrence of diseases in the spring, infecting the young seedlings soon after germination. 6. Piricularia Oryzae hibernating in rice seeds may not lose its vitalityat least for two years, and Ophiobolus Miyabeanus for four years under the same condition. 7. Piricularia Oryzae internal of rice seeds loses its vitality after five minutes in hot water kept at 50°C., while Ophiobolus Miyabeanus at 55°C under the same condition.