Zs. P. Komáromy szerk.: Studia Botanica Hungarica 13. 1979 (Budapest, 1979)
Révay, Ágnes: The metabolism of Pleurotus ostreatus (Jacq. ex Fr.) Kummer, Pleurotus florida Block and Pleurotus cornucopiae Paul. ex Fr. from taxonomical and other viewpoints
Table 2. Internal contents of the initial substrates mg/lg dry matter (for I-VI see Table 1) Substrate Sugar Lignin Cellulose I 99. 3 95. 6 463. 4 II 78. 6 122.0 480. 9 III 193.0 123. 9 442. 6 rv 75. 3 238.4 495. 4 V 212.0 130. 4 386. 5 VI 155. 6 126. 2 377. 2 In Pleurotus ostreatus a similarity expressed on the basis of all the parameters examined was shown between the factory mixture and corn stalk (Tables 3 and 5). This species was of the highest mycelium yield among the 3 species. The times of interweaving did not differ too much in the individual substrates (Table 1), but mycelium production was different during identical times. It was only the thallus diameter that could be measured, the quantity of mycelium could not be measured because it cannot be isolated from the substrate, but in the same time of mycelium production, the utilization of corn stalk proved to be the best. The substrates of the factory mixture and of sorghum stalk were also quite markedly interwoven. The substrate of sawdust was the least interwoven. In Pleurotus florida , smaller differences occurred in the individual culture media. This species was the earliest to produce fruit bodies. Its breaking down of the cellulose was much more considerable in the phase of producing the fruit bodies than was that of Pleurotus ostreatus. Parallel with the high rate of cellulose break-down, the quantity of sugar also increased in the medium. The quantity of sugar, apart from two exceptions, decreased in the beginning, then, in the course of the second sampling, increased at first to a greater extent and then to a lesser one. The initial decrease can probably be explained by the fact that fungi first mainly take up the available free sugar. Cellulose is broken down by them into Dglycose. In the course of the second sampling, the activity of the enzymes breaking down cellulose abruptly increases, which is probably induced by the decrease in the sugar content. In specimens grafted with Pleurotus cornu copiae analyses were carried out only after the interweaving had taken place. At this phase the lignin decomposed the most in the three species. Comparing the individual substrates, we can say that the degree of their utilization depends on the quantity and ratio of their main components (lignin, cellulose, sugar) as well as on their structure (grain size, compactedness). Saw-dust, although it has the highest lignin and cellulose content (Table 2), has not proved to be so satisfactory a substrate due to its compact structure, as for example the corn stalk of looser fibres.
