数種の森林の土壌糸状菌群

Abstract

京大芦生演習林, 奈良県大台ガ原山, 長野県信大演習林, 鹿児島県川内市にある18の森林の有機物層 (F - H層), 表層土壌 (0 - 25cm) から土壌糸状菌を稀釈平板法によって分離した。(I) 分離された糸状菌は胞子形成糸状菌が殆んどであった。Trichoderma, Penicillium はハイマツ群落の土壌層をのぞいて, 他のすべての試料から分離され, 森林の土壌に棲息する糸状菌の中で主要な位置を占めていることが推察された。Mucor, Mortierella もかなり普遍的に分離された。Mortierella sp. P. はコジイ林の土壌層, G. sp. Cryp. I はスギ林の土壌層, G. sp. Picea I. は大台ガ原山トウヒ林の有機物層と土壌層, ヒメシャラ小径木林の有機物層から特徴的に分離された。(II) 同一気候条件のもとでは広葉樹林ならびに広葉樹, 針葉樹の混交林との有機物層から分離された土壌糸状菌の総菌数は針葉樹林の有機物層から分離されたものに比して多かった。なお種数の多少には森林の種類に応じた一定の傾向は認められなかった。(III) 年平均気温がさがるにつれて, 有機物層から分離された土壌糸状菌群の総菌数は, 少なくなった。しかし土壌層から分離された総菌数にはそのような一定した傾向は認められなかった。(IV) 各森林の試料から分離された糸状菌群の類似性をSφrensen Quotient を求めて検討した。ドイツトウヒ林, 柏木スギ林, オオシラベ林, ハイマツ群落, ヒメシャラ・ブナ小径木林は他の林とのQ. S. がひくかった。大台ガ原山ブナ林と同ウラジロモミ・ブナ混交林とのQ. S. 80, 同ブナ林と芦生演習林のブナ, ミズナラの落葉広葉樹林のQ. S. 75, 大台ガ原山ウラジロモミ・ブナ混交林と芦生のブナ・ミズナラ林とのQ. S. 80 が求められた。

The flora of soil fungi from the 18 forest sites were studied by the dilution plate method. The 18 forest sites were the followings : Site 1 (0-P); a pure forest of Picea jezoensis Carr. var. hondoensis. The understory is lacking and the ground flora consists densely and solely of moss (Bryophyta). The soil is a brown forest soil. Site 2 (0-A); an evergreen coniferous mixed Abies homloepis, Tsuga sieboldii and Chamaecyparis obtsusa forest. The understory is lacking and the ground flora consists sparsely of moss. Site 3 (0-F); a Fagus crenata forest. The ground flora consists of bamboograss. Site 4 (0-F.R); a Rhododendron Metternichii cover. The canopies are covered with beechs and maples. The soil is wet brown forest soil and the organic horizon is well develloped. Site 5 (0-F.S.); A deciduous broad leaved mixed Stewartia monadelpha and Fagus crenata forest. The ground is densely covered with bamboograss. After spruce or fir wood had been removed, this forest has been established naturally some dozen years beffore this investigation. Site 6 (A 0-F.); a mixed Abies homolepis, Fagus-crenata and Quercus mongolica var. grosserrata forest. The soil is a wet brown forest soil. Site 1~6 are at the Mt. Odaigahara, Nara Prefecture and are 1500 m above the sea-level. The annual mean temperature is 5.7℃ and the annual precipitiation is 4926 mm. Site 7 (K-F); a deciduous broad leaved mixed forest, dominated Fagus crenata, 1000 m above the sea-level. The annual mean temperature is 8.2℃. Site 8 (K-Q); a forest of Quercus glauca, 450 m above the sea-level. The soil is a dry brown soil. The annual mean temperature is 14.3℃, and the annual precipitation is 2915 mm. Site 9 (KA-Cry.); a forest of Cryptmeria japonica 350 m above the sea-level. The annual mean temperature is 13.8℃ and the precipetation is 1847 mm. This forest has been established about 40 years before this investigation. The understory is lacking and the ground flora consists densely and soley of Iris japonica Thunb. Site 10 (A-P); a pure Picea excelsa forest and is 640 m above the sea-level. Site 11 (A-D); a deciduous broad leaved mixed Fagus crenata, Quercus mongolia and others forest 670 m above the sea-level. The soil is brown forest soil. Site 12 (A-Cry); a mixed forest, dominated Cryptmeria japonica, 700 m above the sea-level. The understory consists of many decieuous and evergreen broad leaved trees. The soil is a weak podzolized soil. Site 10~12 are at the Ashu experimental forest of the Kyoto University. The annual mean temperature is 11.8℃ and the annual precipitation is 2788 mm. Site 13 (S-P. p.) a community of Pinus pumila, about 2800 m above the sea-level. The soil is a weathering granite sandy soil. The annual mean temperature is 0.8℃. Site 14 (S-A); a pure forest of Abies Mariesii, about 2600 m above the sea-level. The soil is wet brown forest soil. The understory is lacking and the ground flora consists of moss. The annual mean temperature is 1.8℃. Site 15 (S-A.T.); a coniferous evergreen mixed Tsuga sieblodii and Abies Mariesii forest, about 2000 m above the sea-level and the ground flora consists of moss and unknown grasses. Site 16 (S-P.d); a forest of Pinus densiflora and has been planted before 30 years. This site is 800 m above the sea-level. The annual mean temperature is 10.8℃ and precipitation is 1243 mm. The understory consists of many sumac and some other deciduous broad leaved trees and the ground is moss cover. The soil is a black forest soil. Site 14~15 are situated in the experimental forest of Shinshu University in Nagano Prefecture. Site 17 (Ky-Cu); a evergreen broad leaved mixed Castanopsis cuspidata and Machilus Thumb. forest. Site 18 (Ky-D); a evergreen and deciduous broad leaved mixed forest. Carpinus chonoskii is the most dominant. Site 17-18 are situated in Sendai, Kagoshima Prefecture. The annual mean temperature is 14.5℃ and the annual precipitation is 2156 mm. Five or six samples were taken from F-H horizon and A horizon in each forest site. In the laboratory, the samples of each horizon were weighed. (I) Most of microfungi isolated were heavily sporing fungi belonging in Phycomycetes and Fungi Imperfecti. Trichoderma and Penicillium were generally and most abandantly isolated throughout from each horizon of the experimented forest site, except the mineral soil horizon at a Pinus pumila stand. Mucor and Mortierella were generally subdominant fungi. Mortierella sp. P was isolated from A horizon in the forest of Custanopis cuspidata, G. sp. Crypt. I from A horizon in the forest of Cryptmeria japonica, and G. sp. Picea I from F-H horizon and A horizon in Picea jezoensis, and F-H horizon in the deciduous broad leaved mixed Stewartia and Fagus forest. (II) Under the same climatic condition, the numbers of fungi isolated from the broad leaved forest and the mixed broad leaved-coniferous forest were more abandant than that from the pure coniferous forest. (III) It was recognized that in the fungal flora isolated from organic horizon, the fungal number decreased with the decrease of the annual mean temperature. (IV) The flora of soil fungi from 18 forest sites were compared with each other by the method of Soerensen. Picea excelsa, Cryptmeria japonica in Kashiwagi, Abies Mariesii, Pinus pumila, and Stewartia monadelpha forest were characterized by a very different microflora of soil microfungi (Q.S. less than 50). On the contrary, the Q.S. between site 3 and site 5, between site 3 and site 10, and between site 5 and site 10 were 75-80.