ISSN 0096-3925, Moscow University Biological Sciences Bulletin, 2007, Vol. 62, No. 1, pp. 15–20. © Allerton Press, Inc., 2007.Original Russian Text © V.P. Prokhorov, V.V. Bodyagin, 2007, published in Vestnik Moskovskogo Universiteta. Biologiya, 2007, No. 1, pp. 19–24.

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The aero-aquatic hyphomycetes (AAHs) are a heter-ogeneous group of fungi that can grow and formconidia in an aqueous medium. The classic Ingoldian(also called amphibious) fungi are usually ascribed toAAH. Several species are characterized by the bivalentbehavior of conidia, including those that are specializedfor diffusion by air currents, while others are spread inaqueous media. Several species of AAH belong to theknown ground saprotrophic or parasitic deutero-mycetes. This ecological group of Hyphomycetes alsoinvolves species belonging to typical ground speciesand are not considered to be true AAHs; they are, how-ever, adapted to the development and to diffusion ofconidia not only in aerial, but also in aqueous media.The representatives of the

Fusarium

and

Speromospora

genera also belong to this group. There is at this time nounequivocal definition of the AAH group.

This group of hyphomycetes has been studied forover 60 years. There are a great number of worksdevoted to the species diversity of AAHs; however,only a few works have been devoted to the ecologicalpeculiarities of the species belonging to AAHs.

The studies of AAHs were carried out in 2004 on theterritory of Bittsa forest park (in River Chertanovka, inthe gully along the river, in the rivulet adjacent to But-lerov Street, and in the gully near the rivulet) and on theterritory of a park adjacent to Moscow State Universitynear the metro station Vorob’evy gory (in a rivulet, in agully near the rivulet, at a pond and its surroundingsnear the Alekseevskii Monastery).

Samples of fallen leaves (both immersed in waterand from the leaf litter and plant residues of monocoty-ledonous and dicotyledonous plants) were collected ateight stationary points during the period from April toOctober. They were then immersed in shallow layers ofwater and incubated in Petri dishes at room temperaturefor 45–60 days. For the first two weeks, the sampleswere investigated every two days, and after that, everyfour to five days. Distilled water was added when thedishes had dried. Samples of foam were taken in theriver and the rivulets; they were fixed in 4% formalde-hyde and then investigated under a microscope in thelaboratory.

The goal of the examination was to reveal the eco-logical characteristics, the time dynamics of develop-ment in a laboratory and in nature, and the interspecialinteractions of AAHs during the incubation of samples.

On the territory investigated, we found 35 species ofAAHs that belong to 21 genera, including conidia offour until now unidentified species of AAHs belongingto the

Clavariopsis, Dactytella, Helicoon

, and

Tetracla-dium

species. We also revealed

Fusarium nivale

and

Spermospora

sp., deuteromycetes closely related to theAAH group of fungi, which were also included in thediscussion. Of the group of soil fungi, representativesof the

Alternaria, Artrobotrys, Helmintosporum

s.l.,

Mucor

, and

Penicillium

genera were found. These rep-resentatives are facultative parasites of plants orsaprophytes, but are capable of the development andformation of conidia on plant residues dipped in water.

The Ecology of Aero–Aquatic Hyphomycetes

V. P. Prokhorov and V. V. Bodyagin

Department of Mycology and Algology, Faculty of Biology, Moscow State University, Vorob’evy gory, Moscow, 119992 Russia

Abstract

—We observed 35 species of aero-aquatic hyphomycetes belonging to 21 genera and 4 unidentifiedtaxa of the

Clavariopsis, Dactilella, Helicoon,

and

Tetracladium

genera. Substrate preferences were detectedin some species. Species such as

Anguillospora longissima, Tetracladium marchalianum

, and

Fusarium aque-ductum

were found on different types of substrata. Only 11 species are developed on pine needles, while 20species were observed on leaves. Eight species of aquatic hyphomycetes (

Alatospora acuminata, Angullosporaaquatica, Lemonniera aquatica, Tetracladium setigerum, Tricladium angulatum, Tripospermum campelopar-dus, Septonema secedens

, and

Spermospora

sp.) were revealed on leaves taken from water habitats, whereas 15species were found in litter. The jointly grown species did not demonstrate any inhibiting effects on each otherexcept for

Tripospermum campelopardus

, which inhibited the growth of other species (Table 3). The microcy-clic development of a

Dactilella

sp. was detected for the first time while being incubated on leaves in the labo-ratory. The frequency of appearance changes, and the diversity of the species of aquatic hyphomycetes appearsto be higher on intact leaves than on skeletonized ones. The seasonal dynamics of aquatic hyphomycetes withtwo peaks of mass conidia development (vernal and sharper autumnal) were described. Some species wereobserved throughout the entire vegetation season. The conidial development in the leaf samples incubated inthe laboratory lasted for 30–40 days. Therefore, the method of incubation for 7–10 days recommended in theliterature did not allow for the complete investigation of species diversity in aquatic hyphomycetes.

DOI:

10.3103/S009639250701004X

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The data in Table 1 indicates the absence of consid-erable differences in the composition of species of themost widely distributed AAHs on the leaves of various

species of trees dipped in water. It is possible that only

Jaculispora submera

may have some affinity for oakleaves.

Quercus robur

was found on five samples of oak

Table 1.

Occurrence of AAHs on various substrates

SpeciesSubstrate

1 2 3 4 5 6 7 8 9 10 11 12 13 14

Alatospora

acuminata

Ing. + + + + + + + + – – + – + +

Actinospora

megalospora

Ing. – – – – – – – – – – – – – +

Anguillospora

crassa

Ing. + – + – + + + + – – – – – +

A

.

curvula

Iqbal – – + + – – – – – – – – – +

A

.

gigantea

Ranz. + – – – – – – – – – – – – +

A

.

longissima

(Sacc. et Syd.) Ing. + + + + + + + + + + + + + +

Angullospora

aquatica

S. Nilss + + + + + + + – – – – – + +

Camposporium

antennatum

Harkness + – + – + + + + – – – – + +

C

.

pellucidum

(Grove) Hughes – – – – + – – – – – – – – +

Clavariopsis aquatica de Wild + + + – – – – + – – – – – +

Clavariopsis

sp. – + + + + + – – – – + – – +

Dactylella

aquatica

(Ing.) Ranz. + – – – – – + – – – – – – +

Dactylella

sp. + + – + – + + – – – – – + +

Flabellospora

verticillata

Alasoadura – – + – – – – – – – – – – –

Flagellospora

curvula

Ing. – – – – + – – – – – – – – –

Fusarium

aqueductum

(Radlk. et Rabh.) Lagh. + + + + + + + + + + + + + +

F

.

nivale

(Fr.) Ces. + + + + + + + + + + + + + +

Helicoon

sp. + – + – – – – – – – – – – +

Heliscus

lugdunensis

Sacc. et Therry + – – – – – – + – – – – – +

Jaculispora

submersa

Hudson et Ing. – – + – – – – – – – – – – –

Lemonniera aquatica de Wild. + + + + + + + – + – + – + +

L

.

centrosphaera

Marv. + + + – + + + – – – + – + +

L

.

terrestris

Tubaki + – – – + – – – – – – – – +

Mycocentrospora

acerina

(Hart.) Deighton – – + – + – – – – – – + – +

Septonema

secedens

Corda + + + + + + + – + – – – + +

Spermospora

sp. + + + + + + + – – + + – + –

Tetracladium

marchalianum

de Wild + + + + + + + + + + + – + +

T

.

setigerum

(Grove) Ing. + + + + + + + – – – + – – +

Tetracladium

sp. – – – – – + + – – – – – – –

Tricladium

angulatum

Ing. + + + + + + + + – – – – + +

Tr

.

gracile

Ing. + – + + – + + – – – – – + +

Tr

.

splendens

Ing. – – + – – – – – – – – – – +

Tripospermum

campelopardus

Ing. et al. + + + + + + + + – – – + + +

T

.

mirtii

(Lind.) Hughes + – + – – – + – – – – – – +

Vargamyces

aquaticus

(Dudka) Toth – – + – – – – – – – – – + –

Varicosporium

elodeae

Kegel – – + – – – – – – – – – – –

V

.

delicatum

Iqbal – – – – – – – – – – – – – +

Total 24 16 27 16 20 19 20 11 6 5 10 5 15 31

Notes: 1, birch; 2, willow; 3, oak; 4, poplar; 5, maple; 6, lime tree; 7, nut tree; 8, pine; 9, pteridophyte; 10, crop plants and sedges;11, dicotyledon; 12, tree residues; 13, ground litter; and 14, foam.

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THE ECOLOGY OF AERO–AQUATIC HYPHOMYCETES 17

leaves dipped in water, which were collected in August,September, and October on the territory of Vorob’evygory park. In the literature, there is information on thefinding of this species on the submerged decayingleaves of an unidentified plant and in the surface film ofthe water (Dudka, 1985).

Pine needles were found to contain only 11 speciesof AAHs, versus the average 20 species found in hard-wood. It is believed that pine needles contain polyphe-nols and terpenoids that seem to inhibit colonization byand the development of AAHs (Bärlocher et al., 1977,1978). Our data confirm this presumption. In fact, wefound that among samples of pine needles that weresufficiently destroyed, pine needles that were blackwith age, and pine needles covered with water for abouta year and no longer having any inhibitor substances,there were nine species of AAHs, whereas pine needlesdevoid of any visible signs of destruction containedfrom zero to three species of hyphomycetes.

The smallest number of species of AAHs found wassix. These species were discovered on the plant resi-dues of pteridophytes, crop plants, sedges, and tree res-idues (five species of AAHs on each substrate type). Atthe same time, 11 species of AAHs were revealed onthe leaves and stalks of dicotyledons.

Three species of AAHs (

Anguillospora longissima,Tetracladium marchalianum

, and

Fusarium aquedu-tum

) were found on each type of substrate studied. Eightspecies of AAHs (

Alatospora acuminate, Angullosporaaquatica, Lemonniera aquatica, Tetracladium setigerum,Tricladium angulatum, Tripospermum campelopardus,Septonema secedense

, and

Spermospora

sp.) were foundon leaf samples from all of the trees studied. The incuba-tion of fallen leaves taken from aboveground habitatsallowed us to identify 15 AAH species.

No antagonistic interactions between various AAHtypes were revealed in the process of incubation. Theonly exception is

T. campelopardus

, which activelyinhibits the mass development of other AAH speciesand the occasional hyphomycete species. The forma-tion of spore carriers of myxomycetes was repeatedlynoticed upon the incubation of leaf samples and otherplant residues. For example, species of myxomycetes,such as

Didymium crustaceum

Fr.,

D. minus

(Lister)Morgan,

D. squamulosum

(Alb. et Schw.) Fr.,

Per-ichaena vermicularis

(Schw.) Rost., and

Physsarumsulphureum

Alb. et Schw., appeared. These myxo-mycete species completed their life cycles in Petridishes, from zoospores to sporangia. An oomycete,

Pythium

sp., was developed simultaneously withAAHs. Note that the occurring frequency of fungi andsimilar organisms not related to AAHs was low, exceptfor myxomycetes (9%). During the development ofeach sample, representatives of the division

Chytridio-mycosa

appeared, but were not identified. An abundantdevelopment of invertebrata, which fed on the decom-positional products of both plant residues and fungalmycelium, was observed in samples.

The phenomenon of microcyclic development ofaero-aquatic hyphomycetes

Dactylella

sp. was foundfor the first time during the incubation of leaf samplesin Petri dishes. Its conidia grew outward as a shorthypha on which new conidia formed (see Fig. 1).

The notion is widely distributed that AAHs are devel-oped most frequently and in abundance on sufficientlydestructed leaves. Hence, it is usually recommended tocollect samples of skeletonized leaves for the identifica-tion of species composition (Dudka, 1974, 1985).

Our studies showed that the frequency of occurrenceand the species composition of AAHs depend on theextent of decomposition in fallen leaves. Some of theobserved correlations between the decomposition offallen leaves and the development of AAH species aregiven in Table 2.

A significant number of AAH species and someamphibious Hyphomycetes have a lignin-destructingcomplex of enzymes (Fisher et al., 1983). The resultsshown in Table 2 indicate that a minimum number ofAAH species is a characteristic of skeletonized leaves.The appearance of

Tripospermum campelopardus,

whichis probably close to the ecological group of

r-strategists, isconcurrent with the initial stages of leaf degradation.The mass development of this species occurs on freshlyfallen leaves, and the substances secreted by it exhibit aclear fungistatic activity. During incubation in Petridishes, its conidia appear before the others, on the firstthrough fourth days (see Table 3). T. campelopardusdisappears after 0.5–1 month of incubation, and duringthis time, the leaves are often degraded to a skeleton-ized state. Other AAHs appeared in the Petri dishesafter the disappearance of T. campelopardus. Speciesthat are likely to have lignin-degrading enzymes andwere found in already skeletonized leaves include the fol-lowing: Alatospora acuminate, Anguillospora crassa,A. curvula, A. longissima, A. aquatica, Fusarium aque-ductum, F. nivale, Lemonniera aquatica, L. centro-

20 µm

50 µm

(a) (b)

Fig. 1. Dactylella sp.: (a) conidia and (b) microcyclic devel-opment.

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Table 2. The dependence of AAH occurrence on the decom-position degree of fallen leaves

AAH species

Occurrence of AAH specieson leaves submersed in water

green

yellow withouttraces of

decompo-sition

skeletized

Alatospora acuminata + + +Anguillospora crassa + + +A. curvula + + +A. gigantea – + –A. longissima + + +Angullospora aquatica + + +Camposporiumantennatum

+ + –

C. pellucidum – + –Clavariopsis aquatica – + –Clavariopsis sp. + + –Dactylella aquatica – + –Dactylella sp. – + –Flabellosporaverticillata

– + –

Flagellospora curvula – + –Fusarium aqueductum + + +F. nivale + + +Helicoon sp. – + –Heliscus lugdunensis – + –Jaculispora submersa – + –Lemonniera aquatica + + +L. centrosphaera + + +L. terrestris – + –Mycocentrosporaacerina

+ + –

Septonema secedens + + +Spermospora sp. + + –Tetracladiummarchalianum

+ + +

T. setigerum + + –Tetracladium sp. – + –Tricladium angulatum + + –Tr. gracile + + –Tr. splendens – + –Tripospermumcampelopardus

+ + –

T. mirtii + + –Vargamyces aquaticus + + –Varicosporium elodeae – + –Total number of species found

21 35 11

sphaera, Septonema secedence, and Tetracladium mar-chalianum.

Table 3 shows that it is possible to select at leastthree groups of AAH species that differ in the time ofconidia appearance during incubation.

(1) To the group with conidia appearing between thesecond and tenth day of incubation, we can assign thefollowing: Alatospora acuminate, Anguillospora cur-vula, Fusarium aqeductum, Heliscus lugdunensis, Tet-racladium marchalianum, Tricladium angulatum, Tri-pospermum campelopardus, T. murii, and Spermo-spora sp.

(2) The group with conidia appearing on the seventhto fifteenth day of incubation includes the following:Anguillospora crassa, A. gigantean, A. longissima,Angullospora aquatica, Camposporium antennatum,C. pellucidum, Clavariopsis aquatica, Clavariopsissp., Dactilella aquatica, Flagellospora curvula, Fusar-ium nivale, Jaculispora submerse, Lemonniera aquat-ica, L. centrosphaera, Tetracladium setigerum, Tetra-cladium sp., Tricladium gracile, Tr. splendens, Septon-era secedens, and Varicosporium elodeae.

(3) The group with conidia appearing 20 days to onemonth or more after the beginning of incubation includesDactilella sp., Flabellospora verticillata, Helicoon sp.,and Vargamyces aquaticus.

An analysis of information given in Table 3 allowsfor the conclusion to be drawn that the complete identi-fication of the species composition of AAHs requiresthe incubation of the samples under investigation for noless that 45–60 days rather than 9–10 days as was rec-ommended in literature. Note however that the signifi-cant number of AAHs form conidia for the first twoweeks.

The data given in Table 4 reveal two peaks of AAHdevelopment: the less pronounced as was recom-mended in literature. A lower activity of the AAHdevelopment is observed in summer months. The sea-sonal dynamic of AAH development is characteristic ofvarious habitats in the temperate climate zones of theNorthern Hemisphere (Dudka, 1974). The followingeight AAH species dominated throughout the duration ofobservations: Alatospora acuminate, Fusarium aque-ductum, F. nivale, Lemonniera aquatica, Tetracladiummarchalianum, T. setigerum, Septonema secedens, andSperospora sp. Two species of AAHs (Anguillosporalongissima and Tricladium angulatum) occurredthroughout the duration of the investigations, except forin June. The species Anguillospora crassa, Heliscus lug-dunensis, Lemonniera centrosphaera, Tricladium grac-ile, Tripospermum campelopardus, and T. murii, weresynchronized with the autumnal maximum of develop-ment.

The maximum number of AAH species appeared inAugust and the minimum in April and June. Research-ers associate the seasonal dynamics of AAHs withleaves falling into the water (they cannot be degradedbefore spring) and the optimal water temperature for

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THE ECOLOGY OF AERO–AQUATIC HYPHOMYCETES 19

the development of AAHs (10–14 (16)°C) (Dudka,1974, 1985; Webster and Descals, 1981). It is alsoknown that the optimal temperature for the develop-

ment of fungi in this group is 25°C (Chauvet andSuberkropp, 1998). The seasonal dynamics of AAHsappears to be due to two factors, including the time of

Table 3. Time peculiarities of AAH appearance

AAH species Appearance day of conidia

The number of samples in which the spe-cies was found

Alatospora acuminata 6 (±3) 36

Anguillospora crassa 14 (±6) 12

A. curvula 5–7 2

A. gigantea 13 1

A. longissima 8 (±3) 45

Angullospora aquatica 13 (±4) 15

Camposporiumantennatum

13 (±3) 12

C. pellucidum 13 1

Clavariopsis aquatica 12 (±5) 5

Clavariopsis sp. 17 (±5) 12

Dactylella aquatica 9–14 4

Dactylella sp. 28 (±9) 13

Flabellosporaverticillata

41 1

Flagellospora curvula 13 1

Fusarium aqueductum 7 (±4) 41

F. nivale 11 (±3) 16

Helicoon sp. 29 (±4) 5

Heliscus lugdunensis 5–7 2

Jaculispora submersa 15 (±2) 5

Lemonniera aquatica 10 (±6) 40

L. centrosphaera 9 (±5) 24

L. terrestris 5–9 3

Mycocentrosporaacerina

12 (±4) 6

Tetracladiummarchalianum

5 (±4) 58

T. setigerum 8 (±5) 27

Tetracladium sp. 15–19 2

Tricladium angulatum 7 (±5) 28

Tr. gracile 12 (±6) 12

Tr. splendens 18 1

Tripospermumcampelopardus

3 (±2) 38

T. mirtii 4–5 3

Septonema secedens 12 (±4) 29

Spermospora sp. 6 (±3) 23

Vargamyces aquaticus 22 (±6) 9

Varicosporium elodeae 12 1

Table 4. The seasonal dynamics of AAHs on the plant resi-dues from the River Chertanovka submersed in water

AAH speciesMonth

IV V VI VII VIII IX X

Alatospora acuminata + + + + + + +

Anguillospora crassa – – – + + + +

A. curvula – – – – + + –

A. gigantea – – – – + – –

A. longissima + + – + + + +

Angullospora aquatica – + + + + – +

Camposporiumantennatum

+ + + + + – –

Clavariopsis aquatica – – – + + – +

Clavariopsis sp. – – + – + – +

Dactylella aquatica – + – – + + +

Dactylella sp. + – + – + + +

Fusarium aqueductum + + + + + + +

F. nivale + + + + + + +

Helicoon sp. – – – – + – –

Heliscus lugdunensis – – – – – + +

Lemonniera aquatica + + + + + + +

L. centrosphaera – – – – + + +

Mycocentrosporaacerina

– + – + – – +

Tetracladiummarchalianum

+ + + + + + +

T. setigerum + + + + + + +

Tricladium angulatum + + – + + + +

Tr. gracile – – – + + + +

Tr. splendens – – – – + – –

Tripospermumcampelopardus

– – – – + + +

T. mirtii – – – – + – +

Septonema secedens + + + + + + +

Spermospora sp. + + + + + + +

Varicosporium elodeae – – – – + – –

The number of species found

12 14 12 16 26 19 23

20

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leaf fall and the temperature of the water; it is also notexcluded that AAH groups exist with different optimaltemperatures.

ACKNOWLEDGMENTSThis work was partially supported by the Russian

Foundation for Basic Research, project no. 03-04-49042.

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Bärlocher, F., Kendrick, B., and Michaelidis, J., Can. J.Bot., 1977, vol. 55, no. 9, pp. 1163–1166.

Chauvet, E. and Suberkropp, K., Appl. and Environm.Microbiology, 1998, vol. 64, no. 4, pp. 1522–1525.

Dudka, I.A., Vodni gidromitsety Ukrainy (AqueousHydromycetes of Ukraine), Kyiv, 1974.

Dudka, I.A., Vodnye nesovershennye griby SSSR (Aque-ous Imperfect Fungi of USSR), Kiev, 1985.

Fisher, P.J., Davey, R.A., and Webster, J., Trans. Brit.Mycol. Soc., 1983, vol. 80, no. 1, pp. 166–168.

Webster, J. and Descals, E., in Biology of ConidialFungi, vol. 1, 1981, pp. 295–355.