The soil under the microscope: the optical examination of a small area of Scots pine litter (Pinus sylvestris L.)

Jean-François Ponge

Description

This is an English translation of three papers in French which have been published in scientific journals in 1984, 1985 and 1988. The present document describes the components of a moder humus profile under Scots pine, as they can be observed under a dissecting and a light microscope. Plant litter debris, roots and animal feces were collected over a small area (5 x 5 cm) in order to be sectioned and stained. All animals and microbes (fungi, bacteria, micro-algae) collected within a small area of litter (5 x 5 cm) were identified to the finest possible taxonomic level. Gut contents were analyzed and compared with the composition of the immediate environment in order to have the most reliable view of trophic relationships between plants, animals and microbes living in the same restricted environment.

Sujets

• Humus
• Bacteria
• Mite
• Moder
• Pine
• Soil
• Enchytraeidae
• Coprophagia
• Microorganism
• Trophic dynamics
• Food chain
• Decomposition
• Fauna
• Litter
• FOREST
• Earthworm
• Nematode
• Springtail
• Fungi

Informations

• Publié par: ponge
• Publié le: 14 juin 2016
• Nombre de lectures: 7
• Langue: English
• Poids de l'ouvrage: 6 Mo

Extrait

The soil under the microscope: the optical examination of a small area of Scots pine litter * (Pinus sylvestrisL.)

Jean-François Ponge

Muséum National d’Histoire Naturelle, CNRS UMR 7179, 4 avenue du Petit-Château, 91800 Brunoy, France, E-mail:[e-mail]

*  English translation of three papers published in French by Ponge (1984, 1985 and 1988). Some parts were rearranged for clarity but no attempt was made to update species and horizon names according to modern literature 1

INTRODUCTION................................................................................................................................. 9

Study site, sampling procedure and field observations.10...................................................................

Preparation of the material for laboratory observation.................................................................. 11

THE L 1 LAYER: RECENTLY FALLEN NEEDLES AND LIVING MOSS.................................12

Decaying needles....................................................................................................................5..............1

Needles without any external sign of fungal attack............................................................................... 15

Needles attacked by parasitic fungi...................................71....................................................................

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Lophodermium pinastri................................................................................................................. 17

Ceuthospora pinastriandLophodermella sp................................................................................ 17

Needles attacked by the saprophyticVerticicladium trifidum .............................................................. 17

Needles attacked byVerticicladium trifidumafterLophodermium pinastriandCeuthospora pinastri 19

Conclusions about decaying needles.....................................................................................................21

Decaying twigs..................................................................................................................................... 21

Bark fragments.................................................................................................................................... 22

Living and decaying moss (Pseusceropodium purum)...................................................................... 23

Fauna.................................................................................................................................................... 23

Inventory................................................................................................................................................ 23

Enchytraeid worms........................................2..3......................................................................................

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Transport on the tegument............................................................................................................. 25

Feeding activity…………………………………………………………………………………..27

Nematodes............................................................................................................................................. 27

Oribatid mites27........................................................................................................................................

Springtails............................................................................................................................................. 29

Fly larvae ………………………………………………………………………………………………………………………………….. 29

Animal faeces....................................................................................................................................... 29

Animal corpses.....................................................................................................................................31

Conclusions about the L 1 layer........................................................................................................... 31 2

THE L 2 LAYER: DECAYING NEEDLES AND DEAD MOSS......................................................32

Decaying pine needles......................................................................................................................... 34

Needles attacked by........................................................................................ 35Verticicladium trifidum

Needles attacked byMarasmius androsaceus ………………………………………………………………………………... 35

Needles attacked by unidentified fungi73..................................................................................................

Needles with bacterial development...................................................................................................... 39

Needles with bacterial and micro-algal development........................................................................... 40

Needles penetrated by enchytraeids...................................................................................................... 39

Hyphal networks embedding decaying pine needles............................................................................. 41

Conclusions about decaying pine needles............................................................................................. 44

Decaying pine twigs............................................................................................................................. 43

Decaying euphylls of pine................................................................................................................... 45

Decaying male flowers of pine............................................................................................................ 45

Decaying branchwood of pine............................................................................................................ 45

Bark....................................................................................................................................................... 46

Wood...................................................................................................................................................... 47

Pine ectomycorrhizae.......................................................................................................................... 49

Decaying moss (Pseudoscleropodium purum).................................................................................... 49

Stems...................................................................................................................................................... 49

Leaves.................................................................................................................................................... 49

Decaying bracken foliage (Pteridium aquilinum).............................................................................. 50

Leaflets.................................................................................................................................................. 50

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Leaflets with limb still present ...................................................................................................... 50

Vein networks................................................................................................................................ 52

Rachises................................................................................................................................................. 52

Fauna.................................................................................................................................................... 52

Inventory................................................................................................................................................ 53

Enchytraeid worms........................................................................................................65........................

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Oribatid mites.................................................................................................06.......................................

Springtails............................................................................................................................................. 62

Fly larvae.............................................................................................................................................. 62

Nematodes............................................................................................................................................. 64

Cyst amoebae........................................................................................................................................ 64

Animal faeces....................................................................................................................................... 64

Macroinvertebrate faeces...................................................................................................................... 64

Enchytraeid faeces................................................................................................................................ 65

Oribatid faeces...................................................................................................................................... 65

Springtail faeces.................................................................................................................................... 69

Animal corpses and corpse fragments............................................................................................... 69

Conclusions about the L 2 layer...........17................................................................................................

THE F 1 LAYER: FRAGMENTED NEEDLES, INVERTEBRATE FAECES AND MYCORRHIZAE.................................................................................................................................73

Decaying pine needles......................................................................................................................... 77

Fungal mantle around pine needles...................................................................................................... 77

Inside of pine needles............................................................................................................................ 79

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Needles attacked byVerticicladium trifidum, but not byCenococcum geophilum..........79.............

Needles attacked byCenococcum geophilum............................................................................... 80

Pine roots and mycorrhizae, mycorrhizal fungi............................................................................... 82

Living roots........................................................................................................................................... 82

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Coralloid orange-brown ectomycorrhizae ..................................................................................... 82

Black ectomycorrhizae .................................................................................................................. 83

Pink ectomycorrhizae .................................................................................................................... 84

Long roots ..................................................................................................................................... 84

Decaying roots...................................................................................................................................... 86

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Short roots ..................................................................................................................................... 86

Long roots ..................................................................................................................................... 87

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Sclerotia ofCenococcum geophilum............................................................................................. 87

Pine twigs............................................................................................................................................. 87

Preliminary remarks.............................................................................................................................. 87

Wood...................................................................................................................................................... 88

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Penetration by basidiomycetes without any attack of lignified walls............................................ 88

Penetration by fungi and bacteria with soft-rot attack................................................................... 88

Bark....................................................................................................................................................... 90

Pine bark.............................................................................................................................................. 90

Notice.................................................................................................................................................... 90

Thin bark fragments.............................................................................................................................. 90

Thick bark fragments............................................19.................................................................................

Pine euphylls........................................................................................................................................ 91

Male flowers of pine............................................................................................................................ 92

Miscellaneous pine material............................................................................................................... 92

Leafy shoots of moss (Pseudoscleropodium purum).......................................................................... 93

Preliminary remarks.............................................................................................................................. 93

Leaves.................................................................................................................................................... 93

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Attack of soft-rot type ................................................................................................................... 93

Attack of white-rot type ................................................................................................................ 93

Stems..93....................................................................................................................................................

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Notice ............................................................................................................................................ 95

Cells with cell contents still present .............................................................................................. 95

Penetration of fungal hyphae......................................................................................................... 95

Penetration of microfauna ............................................................................................................. 95

Hollow moss stems........................................................................................................................ 96

Concluding remarks ...................................................................................................................... 96

Bracken fronds (Pteridium aquilinum).............................................................................................. 96

Bracken leaflets..................................................................................................................................... 96 5

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Bacterial stage ............................................................................................................................... 98

Cenococcumstage ......................................................................................................................... 98

Rachises................................................................89.................................................................................

Birch (Betula pubescensEhrh.).......................................................................................................... 99

Leaves.................................................................................................................................................... 99

Achenes...99...............................................................................................................................................

Mucus................................................................................................................................................. 101

Preliminary remarks............................................................................................................................ 101

Fungal development............................................................................................................................ 101

Decay of the fungus............................................................................................................................. 101

Rhizomorphs...................................................................................................................................... 101

Quartz grains..................................................................................................................................... 103

Spider cocoons................................................................................................................................... 103

Colonies of Chrysophyceae (golden algae)...................................................................................... 103

Fauna.................................................................................................................................................. 103

Inventory.............................................................................................................................................. 103

Protozoa.............................................................................................................................................. 105

Rotifers................................................................................................................................................ 107

Nematodes........................................................................................................................................... 107

Enchytraeid worms..................180............................................................................................................

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Preliminary remarks .................................................................................................................... 108

Generalities.................................................................................................................................. 108

Moss material .............................................................................................................................. 109

Pine tissues .................................................................................................................................. 109

Fungal material............................................................................................................................ 109

Bacteria........................................................................................................................................ 110

Thecamoeban cysts...................................................................................................................... 110

Pine pollen................................................................................................................................... 110 6

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Mesofaunal faeces ....................................................................................................................... 110

Algae ........................................................................................................................................... 112

Intestinal microflora .................................................................................................................... 112

Transport on the tegument........................................................................................................... 112

Oribatid mites..................................................................................................................11....................2

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Generalities.................................................................................................................................. 112

Box mites..................................................................................................................................... 114

Nothrus sylvestris........................................................................................................................ 115

Oppiidae ...................................................................................................................................... 115

Other species ............................................................................................................................... 116

Conclusions ................................................................................................................................. 116

Miscellaneous mites and spiders......................................................................................................... 116

Woodlice.............................................................................................................................................. 117

Springtails........................................................................................................................................... 117

Insect larvae........................................................................................................................................ 120

Animal corpses................................................................................................................................... 121

Preliminary remarks....................................1..21......................................................................................

Enchytraeid worms......................................................................................................212........................

Oribatid mites....................................................................................21.2.................................................

Other arthropods................................................................................................................................. 125

Animal faeces..................................................................................................................................... 125

Type A faeces (slugs?)......................................................................................................................... 125

Type B faeces (woodlice?)................................................................................................................... 126

Type C faeces (earthworms)................................................................................................................ 127

Mineral faeces..................................................................................................................................... 129

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Preliminary remarks .................................................................................................................... 129

White mineral faeces ................................................................................................................... 129

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