Boros István (szerk.): A Magyar Természettudományi Múzeum évkönyve 8. (Budapest 1957)

Bohus, G.: On the results of researches concerning the temperature claims of macroscopic fungi

ANNALES HISTORICO-NATURALES MUSEI NATION ALIS HUNGARICI Tomus VIII. Series nova 1957 On the Results of Researches Concerning the Temperature Claims of Macroscopic Fungi By G. BOHUS, Budapest Numerous authors studied the effects of temperature on the development of fungi. Of the macroscopic fungi, the temperature claims of primarily species causing the decay of wood were examined. We may chiefly refer to the w( rks of Humphrey — S i g g e r s (1933) and Cart w right — Findlay (1934). The dépendance on temperature uf the development of the mycelia or the vegetative portion of the terricûlous macroscopic fungi was hardly investigated. The study of this problem may have its interest from mainly two aspects, first, on the kind cf interrelation between the temperature claims of the mycelia and the fruit bodies of the several species, second, on the rate of the development of the terricolous mycelium in the various temperature seasons of the vegetat onal period. The bulk of the 45 selected fungus species belong to the family Agaricaceae. The n.ycelia of the pure culture of these species grew in test tubes on a 3% malt extract agar, in diffuse light. Generally, the cultures developed, from the time of the inoculation, in room temperature for a week, being brought later to the experimental temperature*. As the results of the researches, the followings could be established : 1. The development of the mycelia of terricolous fungi begins at 3—5° C (Table 1). Between 5—7°, the mycelia of generally all species show a slow development. Some species are exceptional in that their mycelia develop relatively well even on this low temperature , e. g. the mycelium of Collybia mucida grows 7 mm during 10 days, that of Coprinus micaceus 12 mm, that of Morchella hybrida 10 mm, that of Naucina furfuracea 7 mm, that of Psathyrella hydrophila 10 mm, finally, that of Stropharia merdaria 8 mm. This agrees also with field observations, since it was established that the fruit bodies of numerous fungus species — among them those mentioned above — grow rather rapidly even in cold weather. By rising the temperature to 12°, the developmental rate of the mycelia of some species rather increases, yet in the case of the majority of the species, the development of the mycelium reaches an adequate rate only above this temperature. This is shown in Table 2, which displays of how many times the rate of increase of the mycelium observed under 12° rises on optimal temperature. This value, ranging from 2 to 22 in the case of the species studied, may be considered as the index of thennophily ; the higher this value be, the more ,,thermophilous" the mycelium of the species under discussion is. By a further rise in temperature, the developmental rate of the mycelium increases, reaching its maximum around the temperature optimum of 20°. * We were careful to see that the cultures of the identical fungus species placed at sites of various temperatures be cf a uniformly good developmental ability. The number of repetitions were three.