菌類社会学の方法論について (II) : 土着性および発酵性腐生菌類の分布様式

Abstract

土壌微生物は, 土着および発酵性菌類に大別されるが, ここでは, 腐生性菌類 (リター棲息菌2種, 堆肥棲息菌3種) を対象としてとれらの子実体発生の経時的な拡散とその種間の違いについて調べた。さらに接種実験によって子実体分布の拡散を検討した。1. 土着性リター棲息菌 a) 基物の種類 リターの種類 (基物) と土着性菌類 (ヒノキオチバタケ, オチバタケ)の関係は次の3通りが考えられた。第1には特定菌の発生が高い基物である。ここでは部分的に分布するアヤビの葉に発生したヒノキオチバタケ, 普遍的にしかも多量に分布するヒノキ球果にヒノキオチバタケが発現した例が相当した。第2には, 種の発生頻度差のあまりない基物である。ここでは両菌が普遍的にしかも豊富に見られるアカマツの葉, ヒノキの小枝に発現した例が相当した。第3は発生に関与しなかった基物である。ここではヒサカキが比較的多く見られたにも拘らず両菌の侵入対象とはならなかった。b) 空間分布 両菌ともに, 不規則なパターンで, コロニー単位, あるいは個々の子実体単位で拡散してゆくようであった。その分布様式は弱度の集中斑がランダムに分布し集中斑内部もランダム分布であった。およその集中斑の大きさはヒノキオチバタケで156cm_2, オチバタケでは39-78cm_2であった。発生量の年変化が小さいプロットの拡散様式は両菌ともにほぼ同じであったが増減の激しいプロットでは多少の違いが見られた。2. 発酵性堆肥棲息菌 3種ともにリター棲息菌に類似した拡散様式を示したが, 拡散速度は, 明らかに異なった。マルミノヒトヨタケとC. spは交錯した分布領域を保ちながら拡散したが, クズヒトヨタケは, 他者とはっきり分離していた。分布の集中性は, 土着性菌より明白でクズヒトヨタケが0. 03, 0. 25m_2, 他2者は0. 01, 0. 25m_2の2重集中性を示した。 3. 接種実験による拡散 接種後, 最初は全方位に拡散したが, その後の確認は出来なかった。しかし各方位間の拡散速度は一定とはいえなかった。

In this report the author discussed on the spartial and dispersion pattern of sporocarps of a few autochthonous and zymogenous saprobic fungi. Materials used were as follows. Litter-inhabiting fleshy fungi having the organ of rhizomorph (Marasmiellus chamaecyparidis (Hongo) Hongo, (MC) and Marasmius androsaceus (Fr.) Fr., (MA)) in the Japanese cypress chiefly and the Japanese red pine forests as a example autochthonous fungi, compost-inhabiting fleshy fungi (Coprinus kimurae Hongo et Aoki, (CK), C. patouillardii Quél., (CP) and C. sp, (CS)) occurred on the compost which made garbage break into shatters as a example of zymogenous fungi, and mushroom (Agaricus bisporus (Lange) Sing.) occurred on culture bed as a inoculation experiment. Analysis of spartial pattern used Iwao's m*-m relation. On the survey of spartial pattern of populations comprised of the same life form, use of γ･ω and ρ index induced from m*-m relation was effective. 1. Litter-inhabiting fungi a) Response to the substrates It was considered that methods of response of autochthonous fungi to litter were the following three types. 1. Occurrence of a limited species on substrates that partially and anywhere distributed. 2. Occurrence of some species on substrates that abundadantly distributed. 3. No relation to occurrence of fungi. b) Distribution pattern Both MC and MA dispersed with unit of colony or individuals as repeatedly segregating in a irregular pattern. The spartial pattern of both species tended to keep randomly a loose colony and their intra-colony distribution were at random. Approximate clump area of MC was 156 cm2 in plot A, B, C and MA was 39-78 cm2 in plot E, F. The spartial pattern of populations in plots that the annual occurring amounts were stable seemed to be roughly constant, but populations that the amounts were gradually changing seemed to be indicated spartial pattern according to respective condition. 2. Compost-inhabiting fungi CK and CS showed the same dispersion pattern as litter-inhabiting fungi dispersed. These species intersected in density gradients in the opposite directions as keeping territory each other. Territory of CP was clearly separated from these species but method of the dispersion showed similar tendency. Approximate clump of CP was double clump 0.03, 0.25 m2 and CK and CS were also double clump 0.01, 0.25 m2. Colonies of CP were random distribution and that of the other two aggregated, but their intra-colonies distributed at random. 3. On the expansion of fungi inoculated. After the inoculation this species, at first, dispersed to all direction, but the latter occurrence could not to be confirmed. Its dispersion speed between each direction seemed to be not constant.