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Colonization of leaves by water-borne hyphomycetes in a tropical stream
Mycol. Res. 9 2 (4): 392-396 (1989) Printed in Great Britain
392
Colonization of leaves by water-borne hyphomycetes in a tropical stream
K. R. SRIDHAR A N D K. M. KAVERIAPPA Deparfment of Biosciences, Mangalore University, Mangalagangofri 574 199, Mangalore, India
Colonization of leaves by water-borne hyphomycetes in a tropical stream. Mycological Research 92 (4): 392-396 (1989) Sterilized leaf pieces of banyan (Ficus bengalensis), cashew (Anacardium occidenfale),coffee (Coffea arabica), mango (Mangifera indica) and rubber (Hevea brasiliensis) were submerged in the Konaje stream. Sixteen species of hyphomycete colonized the leaves. All colonized banyan leaves, but only six species colonized cashew. Ingoldiella hamata, Lunulospora curvula, Triscelophorw acuminatus, 7. monosporw and 7. konajensis colonized all leaf species, but Alatospora acuminata, Dactylella oviparasitica, Pyramidospora casuarinae and P. constricta colonized only banyan leaves. L. curvula, 7. monosporus and T. konajensis were found to be the major colonizers. More hyphomycetes were encountered during the monsoon and post-monsoon periods than during dry periods. Key words: Tropical streams, Submerged leaves, Water-borne hyphomycetes, Colonization. Water-borne hyphomycetes colonize plant detritus in streams and rivers and act as intermediaries in food chains between plant detritus and invertebrates (Barlocher & Kendrick, 1976, 1981; Suberkropp & Klug, 1976). There are several reports on the colonization of plant materials by water-borne hyphomycetes in temperate streams (Nilsson, 1964; Willoughby & Archer, 1973; Barlocher & Kendrick, 1974; Barlocher et al., 1978; Sanders & Anderson, 1979; Chamier & Dixon, 1982). However, there have been no studies on tropical streams. In work reported here, the colonization of water-borne hyphomycetes on the submerged leaves of commonly occurring plant species has been investigated in a tropical stream.
MATERIALS A N D METHODS The Konaje stream, which joins the Arabian Sea near Uchila, and flows adjacent to Mangalore University campus in Konaje village, Mangalore (India) was selected for the study. The sampling site was at an altitude of 114 mMSL and the vegetation lining the stream is dominated by banyan (Ficus bengalensis L.), cashew (Anacardium occidentale L.), cocoa (Theobroma cacao L.), jack (Artocarpus heterophyllus L.), mango (Mangifera indica L.), tapioca (Manihot utilissima Pohl.) and teak (Tectona grandis L.). Fallen dried leaves of banyan, cashew, coffee (Coffea arabica L.), mango and rubber (Hevea brasiliensis M.), were rinsed in water and each leaf cut into 2 x 10 cm pieces including the midrib. Fifty pieces of each leaf species were sterilized separately in 250 ml conical flasks with 50 ml of distilled water for 1 h at 126 OC. Fifty sterilized pieces of each kind of leaf were sewn into packs and four packs placed in one nylon bag (mesh size 2 mm). Four bags of each kind of leaf were
submerged in the stream tied to rocks and sampled for 1 yr (Dec. 1978-Dec. 1979). Due to extensive decay of the materials after one year, sampling could not be continued, so another set of leaf packs was introduced and observations made for a second year (Dec. 1979-Dec. 1980). Fifty leaf pieces of each species were sampled each month, rinsed in distilled water, cut into small bits and incubated separately in Petri dishes containing distilled water at 25_+Z0. The hyphomycetes that developed on each sample were identified by screening every 2 d under a low-power microscope. After screening, the water in the Petri dishes was replaced by fresh distilled water and the leaf bits reincubated. Observations were carried out for up to 60 d. Colonization of fifty leaf pieces of each species is expressed as a percentage (Table I). Temperature, pH and dissolved oxygen concentration of water were recorded at each sampling time. Data for monthly rainfall for the 2-yr study were obtained from the meteorological observatory located about 2 km from the study area.
RESULTS A N D DISCUSSION A total of sixteen species belonging to thirteen genera of hyphomycetes was observed on the five kinds of submerged leaf (Table 1). All sixteen species were found to colonize banyan leaf material, but only six species colonized cashew leaves. Ingoldielfa hamata, Lunulospora curvula, Trisceiophorus acuminatus, T. monosporus and 7. konajensis colonized all leaf species. Alatospora acuminata, Dactylella oviparasitica, Pyramidospora casuarinae and P. constricta were recorded only on banyan. L. curvula was the most frequently recorded species. It was encountered on all samples except six samplings of rubber. T.monosporus likewise occurred on all samples except
K. R. Sridhar and K. M. Kaveriappa
393
Fig. 1. Colonization of submerged leaves by water-borne hyphomycetes in relation to rainfall, water temperature, pH and dissolved oxygen in Konaje stream. (a) Number of species : B, 1979; mD. 1980; (b) climatic variations : rainfall, @, 1979; 0, 1980; water temperature. A, 1979; A,1980; pH @, 1979; 0, 1980; dissolved oxygen, A,1979; A,1980.
U
8
J
F M A M J
J A S O N D
Months
4
J F M A M J J A S 0 N D Months
three samplings of coffee and two of mango. Percent frequency of colonization of L. curvula was the highest on banyan, coffee and mango, whereas colonization by T. monospurus was the highest on rubber and cashew. Monthly rainfall data, water temperature, pH and dissolved oxygen of Konaje stream and the number of hyphomycete species recorded are presented in Fig. 1. In both years the rains started in the month of April, reached a peak during the month of July and declined thereafter. The total number of hyphomycete species on each leaf species increased with the onset of the south-west monsoon in the month of June and reached peak during July-Aug. : thereafter it decreased and was the lowest during summer (Jan.-May). Alder (Alnus glutinosa) leaves have been found to be the best substratum for colonization by aquatic hyphomycetes in streams in temperate regions (Ingold, 1942; Nilsson, 1964;
Iqbal & Webster, 1973). In the present study the maximum number of hyphomycetes (16 species) was recorded on banyan. Sridhar (1984) recorded 14 species of hyphomycetes on naturally deposited leaves of banyan in the Neriya stream in the Western Ghat forests of Karnataka. He also found the leaves of coffee, rubber, teak, mango and Gleichenia pecfinata Presl. to be good substrata for colonization. Of the species encountered in the present study, 11 species on banyan, 8 species on mango and 6 species on cashew leaves were common. In another study on the submerged leaves of coffee and rubber in the Sampaje stream, Sridhar (1984) recorded 29 species on coffee and 27 species on rubber leaves. All the species recorded on coffee and rubber in the present study were also encountered in the Sampaje stream. The occurrence of a large number of hyphomycetes in the water during the monsoon may be due to heavy rainfall, with
Table 1. Colonization (%)" of water-borne hyphornycetes on submerged leaves 1979
Jan. Feb. Mar. Apr. May June July Aug. Sep. Oct. Nov. Dec.
Total Jan. Feb. Mar. Apr. May June July Aug. Sep. Oct. Nov. Dec. frequencyt
m '3
Banyan
Lunulospora curvula lngold Triscelophorus monosporus Ingold Flagellospora penicillioides lngold Triscelophorus konajensis Sridhar & Kaveriappa Helicosporium sp. Phalangispora constricta Nawawi & Webster Ingoldiella hamata Shaw Triscelophorm acuminatus Nawawi Wiesneriomyces laurinus (Tassi) P. M . Kirk Alafospora acuminata Ingold Beltrania rhombica Penzig Beltrania indica Subram. Dactylella oviparasitica Stirling & Mankau Pyramidospora constricta Singh Dendrospora sp. Pyramidospora casuarinae Nilsson
100 100 76 74 74 0 0 50
Lunulospora curvula lngold Triscelophorus monosporus Ingold Triscelophorus konajensis Sridhar & Kaveriappa Flagellospora penicillioides Ingold Triscelophorw acuminatus Nawawi Wiesneriomyces laurinus (Tassi) P. M . Kirk Phalangispora constricta Nawawi & Webster Ingoldiella hamata Shaw Helicosporium sp. Beltrania rhombica Penzig
100
42
20
34
64
38 0
0 50
0 0
0 0
0 0 0
50 0 0 0 0 0
26 0 0
Coffee 88
100 100 22 82
%
64
788
LOO 749 0 398
82
32
60 341
56 24
62 0
58 261 0 240
38 42
40 20
0 42
176 139
0 0
42 0
0
81
0
74
Lunulospora curvula Ingold Triscelophorus konajensis Sridhar & Kaveriappa Triscelophorw monosporw Ingold Flagellospora penicillioides Ingold Triscelophorw acuminatus Nawawi Beltrania rhombica Penzig Beltrania indica Subram. Ingoldiella hamafa Shaw Wiesneriomyces laurinus (Tassi) P. M . Kirk
Mango 100 100 62 58 100 100 100 100 38 60 40 64 44 0 0 100 86 100 48 100 0 68 100 100 22 42 52 76 0 0 0 0 0 0 0 0
Rubber
Triscelophorus monosporw Ingold Flagellospora penicillioides Ingold Triscelophom aruminatus Nawawi Lunulospora curvula Ingold Triscelophorw konajensis Sridhar & Kaveriappa Helicosporium sp. Wiesneriomyces laurinus (Tassi) P. M . Kirk Ingoldiella hamata Shaw Beltrania rhombica Penzig Triscelophorw monosporw Ingold Lunulospora curvula Ingold Triscelophorw konajensis Sridhar & Kaveriappa Helicosporiurn sp. Ingoldiella hamata Shaw Tricelophorw acurnitzatus Nawawi * Out of 50 leaf pieces of each type of leaf at each sampling. t Out of a total of 1200 leaf pieces of each type of leaf (50 leaf pieces x 24 samplings).
46 60 62 38 48 0 0 26 0
58 68 100 80 44 36 0 42 52
Cashew 100 100 100 78 42 38
58 96 96 66 40 30
100 100 100 76 46 36 76 38 100 24 0 0
Leaf colonization b y water-borne hyphomycetes the result that large amounts of various leaf detritus are transferred into the stream. In studies o n the seasonal occurrence of water-borne hyphomycetes in Konaje stream (Sridhar, 1984; Sridhar & Kaveriappa, 1984), a larger number of species was recorded during the monsoon (Aug.) and postmonsoon (Nov.) periods than in summer (Feb.-May). M a n y investigators have observed similar maxima during wet periods (Willoughby & Archer, 1973; Ingold, 1975; Del Frate & Caretta, 1983). In the present study, L. curvula, T.monosporus and T. konajensis were found t o be the major colonizers of leaf materials in the Konaje stream a t all times of the year. This result is similar t o other seasonal occurrence studies (Sridhar, 1984; Sridhar & Kaveriappa, 1984). Colonization of leaf litter b y water-borne hyphomycetes is controlled b y many factors. Apart from environmental factors, the presence of growth-inhibiting/promoting substances in leaf litter play a major role (Willoughby & Archer, 1973; Suberkropp & Klug, 1976; Triska et al., 1975 ; Triska & Sedell, 1976; Barlocher et al., 1978, 1979; Michaelides & Kendrick, 1978). According t o Barlocher & Oertli (1978a, b) substrata containing inhibitors will be colonized gradually by hyphomycetes after leaching following a period of submergence. Hyphomycetes such as Alatospora acuminafa, Articulospora tetracladia, Heliscus lugdunensis and L. curvula have been reported t o be early colonizers in temperate stream and others like Anguillospora crassa, Centrospora acerina and Dendrospora erecta colonize only after a certain period of submergence (Nilsson, 1964; Iqbal& Webster, 1973; Willoughby & Archer, 1973). In the present study different hyphomycete species were recorded a t different intervals of submergence suggesting the possibility of the influence of chemical changes including the removal of inhibitors b y leaching (Table I). However, preference, competition, differences in growth rate and time required for sporulation may be the other reasons for the delay in the colonization. The authors are indebted t o the staff members of the Department of Biosciences for encouragement. The technical help rendered b y Dr K. Siddappa and M r K. M. Balakrishna, Department of Physics, is gratefully acknowledged.
REFERENCES BARLOCHER,F. & KENDRICK, B. (1974). Dynamics of the fungal population on leaves in a stream. Journal of Ecology 62, 761-791. BARLOCHER,F. & KENDRICK, B. (1976). Hyphomycetes as intermediaries of energy flow in streams. In Recent Advances in Aquatic Mycology (ed. E. B. G. Jones), pp. 435-446. London: Elek Science. BARLOCHER, F. & KENDRICK, B. (1981). Role of aquatic Hypho(Receiued for publication 24 February 1988)
396 mycetes in the trophic structure of streams. In The Fungal Community, its Organiution and Role in the Ecosystem (ed. D. T. Wicklow & G. C. Carroll), pp. 743-760. New York & Basel: Marcel Dekker. BARLOCHER, F., KENDRICK, 8.& MICHAELIDES, J. (1978).Colonization and conditioning of Pinus resinosa needles by aquatic Hyphomycetes. Archiu fur Hydrobiologie 81, 462-474. BARLOCHER, F. & OERTLI, J. J. (1978a). Colonization of conifer needles by aquatic Hyphomycetes. Canadian Journal of Botany 56, 5 7+2. BARLOCHER, F. & OERTLI, J. J. (1978b). Inhibitors of aquatic Hyphomycetes in dead conifer needles. Mycologia 70, 964-974. BARLOCHER, F., OERTLI, J. J & GUGGENHEIM, R. (1979). Accelerated antifungal inhibitors from Pinus leucodermis needles. Transactions of the British Mycological Society 72, 277-281. CHAMIER, A. C. & DIXON, P. A. (1982). Pectinases in leaf degradation by aquatic Hyphomycetes. I. The field study. The colonization-pattern of aquatic Hyphomycetes on leaf packs in a Surrey stream. Oecoiogia 52, 109-1 15. DEL FRATE, G. & CARETTA, G. (1983). Aquatic Hyphomycetes of a mountain stream in Valsesia (Piemonte). Hydrobiologia 102, 69-71. INGOLD, C. T. (1942). Aquatic Hyphomycetes of decaying alder leaves. Transactions of the British Mycological Society 25,339-417. INGOLD, C. T. (1975). Conidia in the foam of two English streams. Transactions of the British Mycological Society 6 5 , 522-527. IQBAL, S. H. & WEBSTER, J. (1973).Aquatic Hyphomycete spora of the River Exe and its tributaries. Transactions of the British Mycological Society 61, 33 1-346. MICHAELIDES, J. & KENDRICK. B. (1978). An investigation on factors retarding colonization of conifer needles by amphibious Hyphomycetes in streams. Mycologia 70, 419-430. NILSSON, S. (1964). Freshwater Hyphomycetes. Symbolae Botanicae Upsafienses IS,5-130. SANDERS, P. F. & ANDERSON, 1. M. (1979). Colonization of wood blocks by aquatic Hyphomycetes. Transactions of the British Mycological Society 73, 103-107. SRIDHAR, K. R. (1984). Studies on water-borne fungi of Dakshina Kannada and Kodagu regions. Ph.D. Thesis, Mangalore University. SRIDHAR, K. R. & KAVERIAPPA, K. M. (1984).Seasonal occurrence of water-borne fungi in Konaje stream (Mangalore), India. Hydrobiologia 119, 101-105. SUBERKROPP, K. & KLUG, M. J. (1976). Fungi and bacteria associated with leaves during processing in a woodland stream. Ecology 57, 707-719. TRISKA, F. J. & SEDELL, J. R. (1976). Decomposition of four species of leaf litter in response to nitrate manipulation. Ecology 57, 783-792. TRISKA, F. J., SEDELL, J. R. & BUCKLEY, B. (1975). The processing of conifer and hardwood leaves in two coniferous streams. 11. Biochemical and nutritional changes. Internationafe Vereinigung fur Theoretische und Angewandte Limnologie, Verhandlungen 19, 1628-1639. WILLOUGHBY, L. G. & ARCHER, J. F. (1973). The fungal spora of a freshwater stream and its colonization pattern on wood. Freshwater Biology 3, 219-239.
392
Colonization of leaves by water-borne hyphomycetes in a tropical stream
K. R. SRIDHAR A N D K. M. KAVERIAPPA Deparfment of Biosciences, Mangalore University, Mangalagangofri 574 199, Mangalore, India
Colonization of leaves by water-borne hyphomycetes in a tropical stream. Mycological Research 92 (4): 392-396 (1989) Sterilized leaf pieces of banyan (Ficus bengalensis), cashew (Anacardium occidenfale),coffee (Coffea arabica), mango (Mangifera indica) and rubber (Hevea brasiliensis) were submerged in the Konaje stream. Sixteen species of hyphomycete colonized the leaves. All colonized banyan leaves, but only six species colonized cashew. Ingoldiella hamata, Lunulospora curvula, Triscelophorw acuminatus, 7. monosporw and 7. konajensis colonized all leaf species, but Alatospora acuminata, Dactylella oviparasitica, Pyramidospora casuarinae and P. constricta colonized only banyan leaves. L. curvula, 7. monosporus and T. konajensis were found to be the major colonizers. More hyphomycetes were encountered during the monsoon and post-monsoon periods than during dry periods. Key words: Tropical streams, Submerged leaves, Water-borne hyphomycetes, Colonization. Water-borne hyphomycetes colonize plant detritus in streams and rivers and act as intermediaries in food chains between plant detritus and invertebrates (Barlocher & Kendrick, 1976, 1981; Suberkropp & Klug, 1976). There are several reports on the colonization of plant materials by water-borne hyphomycetes in temperate streams (Nilsson, 1964; Willoughby & Archer, 1973; Barlocher & Kendrick, 1974; Barlocher et al., 1978; Sanders & Anderson, 1979; Chamier & Dixon, 1982). However, there have been no studies on tropical streams. In work reported here, the colonization of water-borne hyphomycetes on the submerged leaves of commonly occurring plant species has been investigated in a tropical stream.
MATERIALS A N D METHODS The Konaje stream, which joins the Arabian Sea near Uchila, and flows adjacent to Mangalore University campus in Konaje village, Mangalore (India) was selected for the study. The sampling site was at an altitude of 114 mMSL and the vegetation lining the stream is dominated by banyan (Ficus bengalensis L.), cashew (Anacardium occidentale L.), cocoa (Theobroma cacao L.), jack (Artocarpus heterophyllus L.), mango (Mangifera indica L.), tapioca (Manihot utilissima Pohl.) and teak (Tectona grandis L.). Fallen dried leaves of banyan, cashew, coffee (Coffea arabica L.), mango and rubber (Hevea brasiliensis M.), were rinsed in water and each leaf cut into 2 x 10 cm pieces including the midrib. Fifty pieces of each leaf species were sterilized separately in 250 ml conical flasks with 50 ml of distilled water for 1 h at 126 OC. Fifty sterilized pieces of each kind of leaf were sewn into packs and four packs placed in one nylon bag (mesh size 2 mm). Four bags of each kind of leaf were
submerged in the stream tied to rocks and sampled for 1 yr (Dec. 1978-Dec. 1979). Due to extensive decay of the materials after one year, sampling could not be continued, so another set of leaf packs was introduced and observations made for a second year (Dec. 1979-Dec. 1980). Fifty leaf pieces of each species were sampled each month, rinsed in distilled water, cut into small bits and incubated separately in Petri dishes containing distilled water at 25_+Z0. The hyphomycetes that developed on each sample were identified by screening every 2 d under a low-power microscope. After screening, the water in the Petri dishes was replaced by fresh distilled water and the leaf bits reincubated. Observations were carried out for up to 60 d. Colonization of fifty leaf pieces of each species is expressed as a percentage (Table I). Temperature, pH and dissolved oxygen concentration of water were recorded at each sampling time. Data for monthly rainfall for the 2-yr study were obtained from the meteorological observatory located about 2 km from the study area.
RESULTS A N D DISCUSSION A total of sixteen species belonging to thirteen genera of hyphomycetes was observed on the five kinds of submerged leaf (Table 1). All sixteen species were found to colonize banyan leaf material, but only six species colonized cashew leaves. Ingoldielfa hamata, Lunulospora curvula, Trisceiophorus acuminatus, T. monosporus and 7. konajensis colonized all leaf species. Alatospora acuminata, Dactylella oviparasitica, Pyramidospora casuarinae and P. constricta were recorded only on banyan. L. curvula was the most frequently recorded species. It was encountered on all samples except six samplings of rubber. T.monosporus likewise occurred on all samples except
K. R. Sridhar and K. M. Kaveriappa
393
Fig. 1. Colonization of submerged leaves by water-borne hyphomycetes in relation to rainfall, water temperature, pH and dissolved oxygen in Konaje stream. (a) Number of species : B, 1979; mD. 1980; (b) climatic variations : rainfall, @, 1979; 0, 1980; water temperature. A, 1979; A,1980; pH @, 1979; 0, 1980; dissolved oxygen, A,1979; A,1980.
U
8
J
F M A M J
J A S O N D
Months
4
J F M A M J J A S 0 N D Months
three samplings of coffee and two of mango. Percent frequency of colonization of L. curvula was the highest on banyan, coffee and mango, whereas colonization by T. monospurus was the highest on rubber and cashew. Monthly rainfall data, water temperature, pH and dissolved oxygen of Konaje stream and the number of hyphomycete species recorded are presented in Fig. 1. In both years the rains started in the month of April, reached a peak during the month of July and declined thereafter. The total number of hyphomycete species on each leaf species increased with the onset of the south-west monsoon in the month of June and reached peak during July-Aug. : thereafter it decreased and was the lowest during summer (Jan.-May). Alder (Alnus glutinosa) leaves have been found to be the best substratum for colonization by aquatic hyphomycetes in streams in temperate regions (Ingold, 1942; Nilsson, 1964;
Iqbal & Webster, 1973). In the present study the maximum number of hyphomycetes (16 species) was recorded on banyan. Sridhar (1984) recorded 14 species of hyphomycetes on naturally deposited leaves of banyan in the Neriya stream in the Western Ghat forests of Karnataka. He also found the leaves of coffee, rubber, teak, mango and Gleichenia pecfinata Presl. to be good substrata for colonization. Of the species encountered in the present study, 11 species on banyan, 8 species on mango and 6 species on cashew leaves were common. In another study on the submerged leaves of coffee and rubber in the Sampaje stream, Sridhar (1984) recorded 29 species on coffee and 27 species on rubber leaves. All the species recorded on coffee and rubber in the present study were also encountered in the Sampaje stream. The occurrence of a large number of hyphomycetes in the water during the monsoon may be due to heavy rainfall, with
Table 1. Colonization (%)" of water-borne hyphornycetes on submerged leaves 1979
Jan. Feb. Mar. Apr. May June July Aug. Sep. Oct. Nov. Dec.
Total Jan. Feb. Mar. Apr. May June July Aug. Sep. Oct. Nov. Dec. frequencyt
m '3
Banyan
Lunulospora curvula lngold Triscelophorus monosporus Ingold Flagellospora penicillioides lngold Triscelophorus konajensis Sridhar & Kaveriappa Helicosporium sp. Phalangispora constricta Nawawi & Webster Ingoldiella hamata Shaw Triscelophorm acuminatus Nawawi Wiesneriomyces laurinus (Tassi) P. M . Kirk Alafospora acuminata Ingold Beltrania rhombica Penzig Beltrania indica Subram. Dactylella oviparasitica Stirling & Mankau Pyramidospora constricta Singh Dendrospora sp. Pyramidospora casuarinae Nilsson
100 100 76 74 74 0 0 50
Lunulospora curvula lngold Triscelophorus monosporus Ingold Triscelophorus konajensis Sridhar & Kaveriappa Flagellospora penicillioides Ingold Triscelophorw acuminatus Nawawi Wiesneriomyces laurinus (Tassi) P. M . Kirk Phalangispora constricta Nawawi & Webster Ingoldiella hamata Shaw Helicosporium sp. Beltrania rhombica Penzig
100
42
20
34
64
38 0
0 50
0 0
0 0
0 0 0
50 0 0 0 0 0
26 0 0
Coffee 88
100 100 22 82
%
64
788
LOO 749 0 398
82
32
60 341
56 24
62 0
58 261 0 240
38 42
40 20
0 42
176 139
0 0
42 0
0
81
0
74
Lunulospora curvula Ingold Triscelophorus konajensis Sridhar & Kaveriappa Triscelophorw monosporw Ingold Flagellospora penicillioides Ingold Triscelophorw acuminatus Nawawi Beltrania rhombica Penzig Beltrania indica Subram. Ingoldiella hamafa Shaw Wiesneriomyces laurinus (Tassi) P. M . Kirk
Mango 100 100 62 58 100 100 100 100 38 60 40 64 44 0 0 100 86 100 48 100 0 68 100 100 22 42 52 76 0 0 0 0 0 0 0 0
Rubber
Triscelophorus monosporw Ingold Flagellospora penicillioides Ingold Triscelophom aruminatus Nawawi Lunulospora curvula Ingold Triscelophorw konajensis Sridhar & Kaveriappa Helicosporium sp. Wiesneriomyces laurinus (Tassi) P. M . Kirk Ingoldiella hamata Shaw Beltrania rhombica Penzig Triscelophorw monosporw Ingold Lunulospora curvula Ingold Triscelophorw konajensis Sridhar & Kaveriappa Helicosporiurn sp. Ingoldiella hamata Shaw Tricelophorw acurnitzatus Nawawi * Out of 50 leaf pieces of each type of leaf at each sampling. t Out of a total of 1200 leaf pieces of each type of leaf (50 leaf pieces x 24 samplings).
46 60 62 38 48 0 0 26 0
58 68 100 80 44 36 0 42 52
Cashew 100 100 100 78 42 38
58 96 96 66 40 30
100 100 100 76 46 36 76 38 100 24 0 0
Leaf colonization b y water-borne hyphomycetes the result that large amounts of various leaf detritus are transferred into the stream. In studies o n the seasonal occurrence of water-borne hyphomycetes in Konaje stream (Sridhar, 1984; Sridhar & Kaveriappa, 1984), a larger number of species was recorded during the monsoon (Aug.) and postmonsoon (Nov.) periods than in summer (Feb.-May). M a n y investigators have observed similar maxima during wet periods (Willoughby & Archer, 1973; Ingold, 1975; Del Frate & Caretta, 1983). In the present study, L. curvula, T.monosporus and T. konajensis were found t o be the major colonizers of leaf materials in the Konaje stream a t all times of the year. This result is similar t o other seasonal occurrence studies (Sridhar, 1984; Sridhar & Kaveriappa, 1984). Colonization of leaf litter b y water-borne hyphomycetes is controlled b y many factors. Apart from environmental factors, the presence of growth-inhibiting/promoting substances in leaf litter play a major role (Willoughby & Archer, 1973; Suberkropp & Klug, 1976; Triska et al., 1975 ; Triska & Sedell, 1976; Barlocher et al., 1978, 1979; Michaelides & Kendrick, 1978). According t o Barlocher & Oertli (1978a, b) substrata containing inhibitors will be colonized gradually by hyphomycetes after leaching following a period of submergence. Hyphomycetes such as Alatospora acuminafa, Articulospora tetracladia, Heliscus lugdunensis and L. curvula have been reported t o be early colonizers in temperate stream and others like Anguillospora crassa, Centrospora acerina and Dendrospora erecta colonize only after a certain period of submergence (Nilsson, 1964; Iqbal& Webster, 1973; Willoughby & Archer, 1973). In the present study different hyphomycete species were recorded a t different intervals of submergence suggesting the possibility of the influence of chemical changes including the removal of inhibitors b y leaching (Table I). However, preference, competition, differences in growth rate and time required for sporulation may be the other reasons for the delay in the colonization. The authors are indebted t o the staff members of the Department of Biosciences for encouragement. The technical help rendered b y Dr K. Siddappa and M r K. M. Balakrishna, Department of Physics, is gratefully acknowledged.
REFERENCES BARLOCHER,F. & KENDRICK, B. (1974). Dynamics of the fungal population on leaves in a stream. Journal of Ecology 62, 761-791. BARLOCHER,F. & KENDRICK, B. (1976). Hyphomycetes as intermediaries of energy flow in streams. In Recent Advances in Aquatic Mycology (ed. E. B. G. Jones), pp. 435-446. London: Elek Science. BARLOCHER, F. & KENDRICK, B. (1981). Role of aquatic Hypho(Receiued for publication 24 February 1988)
396 mycetes in the trophic structure of streams. In The Fungal Community, its Organiution and Role in the Ecosystem (ed. D. T. Wicklow & G. C. Carroll), pp. 743-760. New York & Basel: Marcel Dekker. BARLOCHER, F., KENDRICK, 8.& MICHAELIDES, J. (1978).Colonization and conditioning of Pinus resinosa needles by aquatic Hyphomycetes. Archiu fur Hydrobiologie 81, 462-474. BARLOCHER, F. & OERTLI, J. J. (1978a). Colonization of conifer needles by aquatic Hyphomycetes. Canadian Journal of Botany 56, 5 7+2. BARLOCHER, F. & OERTLI, J. J. (1978b). Inhibitors of aquatic Hyphomycetes in dead conifer needles. Mycologia 70, 964-974. BARLOCHER, F., OERTLI, J. J & GUGGENHEIM, R. (1979). Accelerated antifungal inhibitors from Pinus leucodermis needles. Transactions of the British Mycological Society 72, 277-281. CHAMIER, A. C. & DIXON, P. A. (1982). Pectinases in leaf degradation by aquatic Hyphomycetes. I. The field study. The colonization-pattern of aquatic Hyphomycetes on leaf packs in a Surrey stream. Oecoiogia 52, 109-1 15. DEL FRATE, G. & CARETTA, G. (1983). Aquatic Hyphomycetes of a mountain stream in Valsesia (Piemonte). Hydrobiologia 102, 69-71. INGOLD, C. T. (1942). Aquatic Hyphomycetes of decaying alder leaves. Transactions of the British Mycological Society 25,339-417. INGOLD, C. T. (1975). Conidia in the foam of two English streams. Transactions of the British Mycological Society 6 5 , 522-527. IQBAL, S. H. & WEBSTER, J. (1973).Aquatic Hyphomycete spora of the River Exe and its tributaries. Transactions of the British Mycological Society 61, 33 1-346. MICHAELIDES, J. & KENDRICK. B. (1978). An investigation on factors retarding colonization of conifer needles by amphibious Hyphomycetes in streams. Mycologia 70, 419-430. NILSSON, S. (1964). Freshwater Hyphomycetes. Symbolae Botanicae Upsafienses IS,5-130. SANDERS, P. F. & ANDERSON, 1. M. (1979). Colonization of wood blocks by aquatic Hyphomycetes. Transactions of the British Mycological Society 73, 103-107. SRIDHAR, K. R. (1984). Studies on water-borne fungi of Dakshina Kannada and Kodagu regions. Ph.D. Thesis, Mangalore University. SRIDHAR, K. R. & KAVERIAPPA, K. M. (1984).Seasonal occurrence of water-borne fungi in Konaje stream (Mangalore), India. Hydrobiologia 119, 101-105. SUBERKROPP, K. & KLUG, M. J. (1976). Fungi and bacteria associated with leaves during processing in a woodland stream. Ecology 57, 707-719. TRISKA, F. J. & SEDELL, J. R. (1976). Decomposition of four species of leaf litter in response to nitrate manipulation. Ecology 57, 783-792. TRISKA, F. J., SEDELL, J. R. & BUCKLEY, B. (1975). The processing of conifer and hardwood leaves in two coniferous streams. 11. Biochemical and nutritional changes. Internationafe Vereinigung fur Theoretische und Angewandte Limnologie, Verhandlungen 19, 1628-1639. WILLOUGHBY, L. G. & ARCHER, J. F. (1973). The fungal spora of a freshwater stream and its colonization pattern on wood. Freshwater Biology 3, 219-239.