Zs. P. Komáromy szerk.: Studia Botanica Hungarica 15. 1981 (Budapest, 1981)

Bohus, Gábor: Some results of systematical and ecological research on Agaricales, VIII

whole space. CO2 concentration of the vessel's atmosphere above the culture medium, densely interlaced with mycelium, was 1.64% at the starting time of the fruit body growth (measured with a "Frenyó" apparatus), that is about ten times the concentration which has already an inhibitory effect in the case of Agaricus bisporus. (I express my gratitude also in this place to Professor V. FRENYÓ for his kind arrangement for carrying out of the measurements). In some cases the fruit bodies formed at the bottom of the vessels where C02 accumulation was the highest, and they grew upwards, along the wall of the glass vessels. After these observations, two problems were to be examined: (1) Interlacing and the appearance of fruit bodies in hermetically closed vessels, (2) What kind of changes can be expected in the growth and the morphology of mycelium during the effect of replacing the atmosphere with C0

2 above the culture medium. Mycelium growth in hermetically closed vessels Two days after inoculation (mixing the culture medium with inoculum), the cover was sealed by means of adhesive tape so that ventilation stopped for 29 days. During this period mycelium interlaced the culture medium in a normal way and the primordia - even in this condition - appeared after such a long time as was taken in the case of ventilation through the wadding filter. After 29 days the adhesive tape was removed. The yield appearing in the subsequent period was of the usual quantity: up to the 83rd day it amounted to 109% in comparison with the dry weight of the culture medium. Number of replications: 2, in a similar way to the preceding one. The production was 100% and 104% respectively. Thus, C0

2 accumulation did not cause inhibition and did not bring about observable changes in the morphology of mycelium. The development of mycelium, densely interlacing the culture medium, and the fact that the synthetization of large quantity, nutritive in necessary for the growth of the rather large fruit bodies the while, seem to indicate that partly even a heterotrophic C0

2 utilization does occur. Mycelium growth in C0

2 atmosphere (1) Inoculum was placed on to the surface of the culture medium. It took 20 days for the mycelium to cover the surface of the culture medium and it intruded into the medium 4 cm deep. Then the normal atmosphere of the culture vessels was substitued for C0

2 and ventilation was stopped in the vessel for 20 days. Under the effect of these conditions mycelium ceased to intrude deeper into the culture medium. (During this time, the mycelium reached the lower level of the culture medium in the control.) After 20 days the normal air condition was replaced. After this, mycelium still stagnated for 1-2 days, then it interlaced also the lower part of the culture medium, (2) Inoculum was mixed with the culture medium. Interlacing reaches such an extent at 25°C during 10 days that the cultures can be put to a temperature at around 17°C, for the inducement of fruit body production. Three experiments were carried out in a way, that after 10 days' interlacing period the normal atmosphere of the vessels was substituted for C0

2 and then the cultures were kept without ventilation. i

n the first case of this série of experiments - it seems - the substitution of the atmosphere for C0

2 could not be successful enough, and after 10 days one fruit body started to grow, earlier than in the case of the control (seemingly the remaining small quantity of oxygen made it possible that C0

2 inhibition could not yet prevail). Then C0

2 was removed. In the medium treated with CO2 the fruit body production was 122%, during 90 days, from the beginning of inoculation in the C0

2 treated cultures, while in the control it was 109%. In the second experiment the procedure was the same as in the first one. During the 30 days while the cultures were kept in C0

2 atmosphere, no change could be visible. After C0

2 removal, the life activity of the fungus continued. The production was 56% during 90 days in the case of CO2 treatment, while in the control it was 103%. A production of 56% is equivalent to the value as usual for 60 days, thus C0

2 treatment, lasting for 30 days, had no harmful effect on the cultures, it only caused a stagnation. Apparently, during the third experiment - the procedure was identical with that of the