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Contribution to the fungal flora of Kuwait
[ 547 ] Trans. Br. mycol. Soc. 65 (3), 547-553 (1975) Printed in Great Britain
CONTRIBUTION TO THE FUNGAL FLORA OF KUWAIT By A. F. MOUSTAFA Department
of Botany, (With
AND
A. A. AL-MUSALLAM
Unioersity oj Kuwait, Kuwait I
Text-figure)
Eighty-two species and forty-four genera were isolated from forty composite soil samples representing salt marshes, salt depressions, and coastal sands. In general the fungal population of saline soils was rather poor with a narrow spectrum of genera and species. The most frequent fungi were Aspergillus, Penicillium, Alternaria, Coniothyrium, Stachybotrys, Fusarium, Cephalosporium, Ulocladium, Myrothecium, and Drechslera, Osmophilic and osmotolerant fungi were isolated on Czapek's agar containing 40 % sucrose. Only three species were found to be highly osmophilic while the rest showed various degrees of osmotolerance.
The State of Kuwait lies on the north of the Arabian Gulf (Fig. I). The general topography is flat to gently undulating with few elevations and wadis (Milton, 1967; Fuchs, Gattinger & Holtzer, 1968). Most of the soils of Kuwait are desert (sandy, gypsiferus and saline) and few alluvial (Ergun, 1964). The climate is typically arid with hot dry summers and cool rainy winters. The present work was concerned with the fungi of saline soils. It represents the first of series of investigations which deal with the soil fungi of Kuwait which have never been surveyed. HABITATS AND METHODS
Saline soils of Kuwait extend along the coastal line, and are represented by three habitats: (I) Salt marshes; extending along the bay of Kuwait to the north borders, with a maximum width of 5 km. The pioneer vegetation consists of Halocnemon strobilaceum within the tidal line, and Zygophyllum coccineum outside. (2) Salt depressions; lie at about 500 m from the water edge in the southern part of the country, with a maximum width of 5 km. The flora is dominated by H. strobtlaceum, Z. coccineum, Salsola barysoma, and Nitraria
retusa. (3) Coastal sands; different areas along the coast, where the dominant plants are Panicum turgidum and N. retusa. A first series of twenty composite soil samples were collected from salt marshes (within and outside the tidal line), salt depressions, and coastal sands between November 1971 and May 1972. Soil samples (500 g each) were taken from ten spots in each site and
Transactions British Mycological Society 30'
47°
o I
30'
20 ,
30'
30' ~ Salt marshes V,,~¢'!
Fig.
I.
Salinedepressions
Outline map of Kuwait, showing the relative area of saline soils from which soil samples were collected.
thoroughly mixed to form a composite sample. The samples were collected about 5 ern from the roots of dominant plants in each site. The dilution-plate method was adopted for the estimation of the fungal flora as described by Johnson et at. (1960), but replacing the pipettes by Menzies's dipper (1957). Modified Czapek's agar was used in which glucose (IO g/l) replaced sucrose. Rose bengal was incorporated as a bacteriostatic agent at a concentration of 1/15000 (Smith & Dawson, 1944). A dilution of I/IO gave an appropriate colony count. Six replicates were used for each composite sample. Plates were incubated at 27 DC, and examined at z-day intervals, and after IO days the fungal colonies were identified and counted. Mycelial fragments from non-identified colonies were transferred to Czapek's agar-j-o-y % yeast extract, or to malt extract. To investigate whether there was a flora of osmophilic or osmotolerant species, a second series of twenty composite soil samples were collected from the same spots during April 1973, and dilution plates were made on Czapek's agar (+ rose bengal) supplemented with 40 % sucrose (Hudson, 1972). All isolates were tested for growth on Czapek's agar with 20, 40, and 60 % sucrose.
Kuwait fungi. A. F. Moustafa and A. A. Al-Musallam T able
I.
Soil no. I
2 3 45
6 7 8 9
10 JJ
12 13 1415 16 17 18 19 20
549
Locality, percentage salinity, total counts (per g dry soil) and number of genera and species in the twenry soil samples (fi rst series) L oca lity
% salin ity
Salt m a rsh* Sa lt m arsh Salt m a rsh* Salt marsh Salt marsh* Sa lt m a rsh Salt m a rsh * Salt marsh Sal t d epression Salt d ep ression Sa lt d epression Sa lt d ep ression Coastal sa nd Coas tal sand Coastal sand Coastal sand Coastal sand Salt depression Salt depression Salt depression
1,6 2'42'46'42'46'42'44-.8 24-'0 10'416'7 8'0 1·6 0·8 0·8 1·6 0·8 16.48·8 14-.8
T otal count
58 75 ISO
80 14-0 6496 105 84-8 616 998 820 960 1220 1525 84-0 880 4-75 680 565
No, of sp ecies
No. of genera
7 9 7 8 9 8 6 8 9
6 8 7 6 8 7 3 8 7 9 12
II
16 14-
"1413 15 13 10
"
12
II
5
6 12 12 8 8 10 10
* Soil samples collec ted from sites within th e tidal line.
R ESULT S
Nat ure oj soil andfungi isolated The results given in T able 1 showed that th e total salinity vari ed m arkedl y, no t only from one locality to another, but from site to site in the same locality. It r anged betw een 0·8 and 1·6 % in coastal sa nds, 1·6 and 6'4 % in salt marshes, and 8'0 and 24 % in salt depressions. In general, saline soils were found to be poor in their fungal content. The number ofpropagules varied greatly, but no t significa ntly, from on e locality to another. The samples collected from salt m arshes yielded the lowest counts (s 8/g soil) of fungi while coastal sa nd soil possessed the highest ones (ls2S/g soil). In the majority of samples, high fun gal content was accom p anied by wide range of genera and speci es, Eighty-two species wer e recov ered from the tw o series of soil samples. Phycomycetes were represented by only 5 species, Ascomycet es 38 species, Coclomycetes 5, and remainder (42 spp.) were Hyphomycetes. The widest spectrum of species was displayed by the genus Aspergillus, being represented by 14 species followed by Alternaria (6 spp.), Fusarium (4 spp.), and Penicillium (4 spp.). M ost of th e remaining gen era wer e represented by only one or two sp ecies. The species of fungi isolated on Cz apek's agar containing 3 % (first series of soil samples) and 40 % suc rose (second series ) are listed in T able 2, whe re they have been arrange d in three groups according to their growth on high sugar concentra tion s of 60, 20-40, and 3-10 %. According to the frequency of occurrence (expressed as the number of isolations from the 20 soil samples), the fungi isolated could be classified
Transactions British Mycological Society
55°
Table 2. Species offungi arranged according to their growth on high sugar concentrations of 10, 20, 40, and 60 % (thefigures represent frequency of occurrence, expressed as the number of isolations from the twenty soil sampleJ) Frequency of occurrence
,
Group A Highly osmophilic (best growth at 60 % sucrose) B Strong osmotolerant (best growth 2(}--40 %)
Species
On
3
Aspergillus repens A. amstelodami A. restrictus A. niger A. terreus A. ochraceus A. sydowii A. nidulans Ai flaoipes Ai flauus Ai fumigatus A. versicolor A. cameus A. candidus Penicillium notatum P. chrysogenum P. crustosum Paecilomyces variotii P. terricola Alternaria alternata A. tenuissima A. raphani A. chlamydospora A. phragmospora A. cheiranthi Drechslera spicifera D. hawaiiensis Curvularia ellisii Ulocladium consortiale U. Chartarum U. oudemansii Fusarium equiseti F. concolor F. acuminatum C. Cladosporoides Stachybotrys atra Phomafimeti Myrothecium verrucaria M. roridum Coniothyrium fuckelii
C Weak osmotolerant (best growth at 3-10%)
Scolecobasidium variabile F. semitectum Microascus cinereus Cephalosporium sp. Mucor circinelloides Chaetomium globosum C. spirals C. olivaceum Thielaviu terricola Arachniotus desertorum Aureobasidium sp. Trimmatostroma sp, Pithomyces atro-olioaceum Actinomucor elegans Humicola grisea Emericellopsis minima For rare occurrence fungi see text.
% sucrose 43 18 1442
On
40
% sucrose 15 13 10
9 II II
7
7
0 8
3
10 0
6 5
7
5
7
4-
0 12 12
9 12
5
7
3 0 12 2 2 14-
42 12
6
6
5 0 12
3
0
5 9
6
3
4-
7 6
3 10 0 0
8 10
7 6
7
0 0 12 0
I
4II
3 10 8 12 3 3 410 4-
6 3 2
3 3 3 3 3
5 40
5 40 0 0 [
0 40 0
6 0 0 0
0 0 2 0 2
Kuwait fungi. .4. F. Moustafa and A. A. Al-Musallam
551
into [our groups. Group I includes high occurrence fungi which are isolated 10-20 times out of 20. It was represented by 16 species, 3 of which are highly osmophilic while the others are strongly osmotolerant. The members of this group are species belonging to the genera of Aspergillus, Penicillium, Alternaria, Coniothyrium, Stachybotrys, Myrothecium, Fusarium, and Cephalosporium. Group II consists of moderate occurrence fungi (isolated 6-9 times) and represented by twelve species, the majority of which arc also strongly osmotolerant. It contains some species of Aspergillus, Penicillium,Fusarium, Drechslera, Ulocladium, and Chaetomium. Group III contains low occurrence fungi (isolated 3-5 times), that comprised sixteen species, some of which are strongly while the others are weakly osmotolerant. In group IV are placed those species of rare occurrence, which are isolated less than three times (not included in Table 2). Most of the members included in this group are weak osmotolerants. It comprised Penicillium lanosum, Petriellidium desertorum, Microascus trigonosporus, Emericellopsis glabra, Myxotrichum deflexum, Scopulariopsis brevicaulis, S. candida, Tritirachium album, Fusariella opstipa, Memnoniella echinata, Camarosporium aequivocum, Pleospora infectoria, Fusarium solani, Cladosporium herbarum, Mucor circinelloides, Pseudodiplodia sp., Rhizopus stolonifer, R. arrhizus, Cunninghamella sp., Stemphylium botryosum, Hendersonia sp., Phialophora sp., Sepedonium sp., Pithomyces maydicus, Thermoyces lanuginosus, and Sporotrichum thermophile.
Osmophilic and osmotolerant species To differentiate between osmophilic and osmotolerant species among all the isolated organisms in this investigation, their spores or mycelial fragments were inoculated on Czapek's agar supplemented with various concentrations of sucrose, 10, 20, 40, and 60 %. The colony diameters were measured and compared. From the results three major groups were recognized (Table 2). A, highly osmophilic; consists of fungi showing their best growth at 60 %. This group includes only three species namely Aspergillus repens, A. amstelodami, and A. restrictus. B, Strong osmotolerant; represented by thirty-eight species, constituting the major part of the recovered species. This group contains those organisms which showed their best growth at 20 or 40 %, but were also capable of making a reasonable amount of growth at 60 %. C, Weak osmotolerant; includes those fungi which showed their maximum growth at IO or 3 % (control) and might also grow at 20 or 40 %, but failed completely to grow at 60 %. This last group was represented by fifteen species, most of which were infrequently isolated. DISCUSSION
The main features of the mycoflora inhabiting saline soils was the preponderance of a limited number of genera and species as compared to normal soils (Bayliss Elliot, 1930; Saito, 1952; Pugh, 1962). This may be an effect of high pH (Jensen, 193I), and poor aeration resulting from the regular flooding of these soils by sea water (Pugh, 1962). Since the total count of soil fungi fluctuates, in response to the method employed for isolation of soil fungi as well as to any slight variation in the
552
Transactions British Mycological Society
chemical, physical, and ecological conditions, it was more suitable to rely on the frequency of occurrence (number of isolations) offungal individuals rather than on the total counts of these fungi (Moubasher & Moustafa, 1970). . In the present work, a total of 82 species belonging to 44 genera were collected. The most frequent species were those belonging to the genera; Aspergillus, Penicillium, Fusarium, Alternaria, Myrothecium, Cephalosporium, Coniothyrium and Stachybotrys. Most of those fungi are strong osmotolerants. A very similar order of dominance was also observed by Sparrow (1937), Stover (1955), Domsch (1960), Griffin (1963), and Chen (1964) who attributed the abundance of those fungi to their ability to thrive at low oxygen tensions, and limited water activities. The term osmophilous fungi is used in a general sense referring to fungi growing better on media containing high sugar concentrations. These osmophilous species which are easily missed in most routine isolation work, as they are frequently overgrown by fast growing fungi, could be isolated in higher frequencies of occurrence (but not necessarily in higher counts) when the isolation media are amended by higher concentrations of sugar or salt. The employment of these high concentrations gives these fungi a better chance to germinate freely and give rise to colonies, since at such higher osmotic pressures few fungi could develop, with a smaller degree of competition. Thirty-four osmophilous species (Table 2, second column) were recovered from plates of Czapek's agar supplemented with 40 % sucrose as recommended by Hudson (1972). During this work four main observations were noted. First, most of those osmophilous species were also recorded on normal Czapek's (3 %) with more or less similar frequency of occurrence. Secondly, some few species like Aspergillus repens and A. amstelodami, which were not seen on isolation plates with normal Czapek's, were encountered with high frequency of occurrence in high osmotic media. Thirdly, some fungi showed a marked increase in their frequency of occurrence on 40 % sucrose compared with 3 %. This trend was well indicated by Aspergillus niger, A. fumigatus, Ulocladium consortiale, and Chaetomium olivaceum. However, some others showed the opposite trend, i.e. either recorded in lower frequency or failed to develop and accordingly not recorded on 40 % sucrose. Fourthly, when all the fungi isolated during this investigation were grown on various concentrations of sucrose, from 3 to 60 %, very few species proved to be highly osmophilic while the other species showed various degrees of osmotolerance. These observations indicate that the mycoflora of saline soils does not only consist of osmophilic species but also contains other species with varying degrees of osmotolerance. The authors are most grateful to all the members of the C.M.I., Kew, England, and C.B.S. Baarn, Holland, for their kind help in checking the identifications of several species reported in this investigation.
Kuwait fungi. A. F. Moustafa and A. A. Al-Musallam
553
REFERENCES
BAYLISS ELLIOT,]. S. (1930). The soil fungi of the Dovey salt marshes. Annals if applied Biology 17, 248-305. CHEN, A. W. (1964)' Soil fungi with high salt tolerance. Transactions of the Kansas Academy if Science 67, 36-40 . DOMSCH, K. H. (1960). Das Pilzspektrum einer Boden Probe. I I Nachweis physiologischer Merkmale. Archio fiir Mikrobiologie 35,229-247. ERGUN, H. (1964). Reconnaissance soil survey. Report to the Government of Kuwait. FAO/KU/TF 17. Mimeo, 16 pp. FUCHS, W., GATTINGER, E. T. & HOLZER, F. H. (1968). Explanatory test to the synoptic geological map of Kuwait. Vienna: Geological Survey of Austria. GRIFFIN, D. M. (1963). Soil physical factors and the ecology of fungi. III. Activity of fungi in relatively dry soils. Transactions of the British Mycological Society 46,373-377. HUDSON, H.]. (1972). Fungal saprophytism. London: Edward Arnold Ltd. ]ENSEN, H. L. (1931). The fungus flora of the soil. Soil Science 31, 123-158. ] OHNSON, L., CURL, E., BOND,]. & FRIBOURG, H. (1960). Methodsfor studying soil microfloraplant disease relationship. Minneapolis: Burgess Publishing Company. MENZIES, ]. D. (1957). A dipper technique for serial dilutions of soil for microbial analysis. Soil Society of America Proceedings 21, 660. MILTON, D. I. (1967). Geology of the Arabian Peninsula. Kuwait. United States Geological Survey, Professional Papers 560-F, 1-7. MOUBASHER, A. H. & MOUSTAFA, A. F. (1970). A survey of Egyptian soil fungi, with special reference to Aspergillus, Penicillium, and Penicillium-related genera. Transactions if the British Mycological Society 54, 35-44. PUGH, G.]. F. (1962). Studies of fungi in coastal soils. 11. Fungal ecology in a developing salt marsh. Transactions of the British Mycological Society 45, 560-566. SAITO, T. (1952). The soil fungi ofa salt marsh and its neighbourhood. Ecological Review, Sendai 13, I I I-I 19. SMITH, N. R. & DAWSON, V. T. (1944). The bacteriostatic action of rose bengal in media used for the plate counts of soil fungi soil. Science 58, 467-471. SPARROW, F. K. (1937). The occurrence of saprophytic fungi in marine muds. Biological Bulletin, Woods Hole 73, 242-248. STOVER, R. H. (1955). Flood Fallowing for eradication of Fusarium oxysoporumf, cubense. III. Effect on fungus survival. Soil Science 80, 397-412.
(Acceptedfor publication
21
April 1975)
CONTRIBUTION TO THE FUNGAL FLORA OF KUWAIT By A. F. MOUSTAFA Department
of Botany, (With
AND
A. A. AL-MUSALLAM
Unioersity oj Kuwait, Kuwait I
Text-figure)
Eighty-two species and forty-four genera were isolated from forty composite soil samples representing salt marshes, salt depressions, and coastal sands. In general the fungal population of saline soils was rather poor with a narrow spectrum of genera and species. The most frequent fungi were Aspergillus, Penicillium, Alternaria, Coniothyrium, Stachybotrys, Fusarium, Cephalosporium, Ulocladium, Myrothecium, and Drechslera, Osmophilic and osmotolerant fungi were isolated on Czapek's agar containing 40 % sucrose. Only three species were found to be highly osmophilic while the rest showed various degrees of osmotolerance.
The State of Kuwait lies on the north of the Arabian Gulf (Fig. I). The general topography is flat to gently undulating with few elevations and wadis (Milton, 1967; Fuchs, Gattinger & Holtzer, 1968). Most of the soils of Kuwait are desert (sandy, gypsiferus and saline) and few alluvial (Ergun, 1964). The climate is typically arid with hot dry summers and cool rainy winters. The present work was concerned with the fungi of saline soils. It represents the first of series of investigations which deal with the soil fungi of Kuwait which have never been surveyed. HABITATS AND METHODS
Saline soils of Kuwait extend along the coastal line, and are represented by three habitats: (I) Salt marshes; extending along the bay of Kuwait to the north borders, with a maximum width of 5 km. The pioneer vegetation consists of Halocnemon strobilaceum within the tidal line, and Zygophyllum coccineum outside. (2) Salt depressions; lie at about 500 m from the water edge in the southern part of the country, with a maximum width of 5 km. The flora is dominated by H. strobtlaceum, Z. coccineum, Salsola barysoma, and Nitraria
retusa. (3) Coastal sands; different areas along the coast, where the dominant plants are Panicum turgidum and N. retusa. A first series of twenty composite soil samples were collected from salt marshes (within and outside the tidal line), salt depressions, and coastal sands between November 1971 and May 1972. Soil samples (500 g each) were taken from ten spots in each site and
Transactions British Mycological Society 30'
47°
o I
30'
20 ,
30'
30' ~ Salt marshes V,,~¢'!
Fig.
I.
Salinedepressions
Outline map of Kuwait, showing the relative area of saline soils from which soil samples were collected.
thoroughly mixed to form a composite sample. The samples were collected about 5 ern from the roots of dominant plants in each site. The dilution-plate method was adopted for the estimation of the fungal flora as described by Johnson et at. (1960), but replacing the pipettes by Menzies's dipper (1957). Modified Czapek's agar was used in which glucose (IO g/l) replaced sucrose. Rose bengal was incorporated as a bacteriostatic agent at a concentration of 1/15000 (Smith & Dawson, 1944). A dilution of I/IO gave an appropriate colony count. Six replicates were used for each composite sample. Plates were incubated at 27 DC, and examined at z-day intervals, and after IO days the fungal colonies were identified and counted. Mycelial fragments from non-identified colonies were transferred to Czapek's agar-j-o-y % yeast extract, or to malt extract. To investigate whether there was a flora of osmophilic or osmotolerant species, a second series of twenty composite soil samples were collected from the same spots during April 1973, and dilution plates were made on Czapek's agar (+ rose bengal) supplemented with 40 % sucrose (Hudson, 1972). All isolates were tested for growth on Czapek's agar with 20, 40, and 60 % sucrose.
Kuwait fungi. A. F. Moustafa and A. A. Al-Musallam T able
I.
Soil no. I
2 3 45
6 7 8 9
10 JJ
12 13 1415 16 17 18 19 20
549
Locality, percentage salinity, total counts (per g dry soil) and number of genera and species in the twenry soil samples (fi rst series) L oca lity
% salin ity
Salt m a rsh* Sa lt m arsh Salt m a rsh* Salt marsh Salt marsh* Sa lt m a rsh Salt m a rsh * Salt marsh Sal t d epression Salt d ep ression Sa lt d epression Sa lt d ep ression Coastal sa nd Coas tal sand Coastal sand Coastal sand Coastal sand Salt depression Salt depression Salt depression
1,6 2'42'46'42'46'42'44-.8 24-'0 10'416'7 8'0 1·6 0·8 0·8 1·6 0·8 16.48·8 14-.8
T otal count
58 75 ISO
80 14-0 6496 105 84-8 616 998 820 960 1220 1525 84-0 880 4-75 680 565
No, of sp ecies
No. of genera
7 9 7 8 9 8 6 8 9
6 8 7 6 8 7 3 8 7 9 12
II
16 14-
"1413 15 13 10
"
12
II
5
6 12 12 8 8 10 10
* Soil samples collec ted from sites within th e tidal line.
R ESULT S
Nat ure oj soil andfungi isolated The results given in T able 1 showed that th e total salinity vari ed m arkedl y, no t only from one locality to another, but from site to site in the same locality. It r anged betw een 0·8 and 1·6 % in coastal sa nds, 1·6 and 6'4 % in salt marshes, and 8'0 and 24 % in salt depressions. In general, saline soils were found to be poor in their fungal content. The number ofpropagules varied greatly, but no t significa ntly, from on e locality to another. The samples collected from salt m arshes yielded the lowest counts (s 8/g soil) of fungi while coastal sa nd soil possessed the highest ones (ls2S/g soil). In the majority of samples, high fun gal content was accom p anied by wide range of genera and speci es, Eighty-two species wer e recov ered from the tw o series of soil samples. Phycomycetes were represented by only 5 species, Ascomycet es 38 species, Coclomycetes 5, and remainder (42 spp.) were Hyphomycetes. The widest spectrum of species was displayed by the genus Aspergillus, being represented by 14 species followed by Alternaria (6 spp.), Fusarium (4 spp.), and Penicillium (4 spp.). M ost of th e remaining gen era wer e represented by only one or two sp ecies. The species of fungi isolated on Cz apek's agar containing 3 % (first series of soil samples) and 40 % suc rose (second series ) are listed in T able 2, whe re they have been arrange d in three groups according to their growth on high sugar concentra tion s of 60, 20-40, and 3-10 %. According to the frequency of occurrence (expressed as the number of isolations from the 20 soil samples), the fungi isolated could be classified
Transactions British Mycological Society
55°
Table 2. Species offungi arranged according to their growth on high sugar concentrations of 10, 20, 40, and 60 % (thefigures represent frequency of occurrence, expressed as the number of isolations from the twenty soil sampleJ) Frequency of occurrence
,
Group A Highly osmophilic (best growth at 60 % sucrose) B Strong osmotolerant (best growth 2(}--40 %)
Species
On
3
Aspergillus repens A. amstelodami A. restrictus A. niger A. terreus A. ochraceus A. sydowii A. nidulans Ai flaoipes Ai flauus Ai fumigatus A. versicolor A. cameus A. candidus Penicillium notatum P. chrysogenum P. crustosum Paecilomyces variotii P. terricola Alternaria alternata A. tenuissima A. raphani A. chlamydospora A. phragmospora A. cheiranthi Drechslera spicifera D. hawaiiensis Curvularia ellisii Ulocladium consortiale U. Chartarum U. oudemansii Fusarium equiseti F. concolor F. acuminatum C. Cladosporoides Stachybotrys atra Phomafimeti Myrothecium verrucaria M. roridum Coniothyrium fuckelii
C Weak osmotolerant (best growth at 3-10%)
Scolecobasidium variabile F. semitectum Microascus cinereus Cephalosporium sp. Mucor circinelloides Chaetomium globosum C. spirals C. olivaceum Thielaviu terricola Arachniotus desertorum Aureobasidium sp. Trimmatostroma sp, Pithomyces atro-olioaceum Actinomucor elegans Humicola grisea Emericellopsis minima For rare occurrence fungi see text.
% sucrose 43 18 1442
On
40
% sucrose 15 13 10
9 II II
7
7
0 8
3
10 0
6 5
7
5
7
4-
0 12 12
9 12
5
7
3 0 12 2 2 14-
42 12
6
6
5 0 12
3
0
5 9
6
3
4-
7 6
3 10 0 0
8 10
7 6
7
0 0 12 0
I
4II
3 10 8 12 3 3 410 4-
6 3 2
3 3 3 3 3
5 40
5 40 0 0 [
0 40 0
6 0 0 0
0 0 2 0 2
Kuwait fungi. .4. F. Moustafa and A. A. Al-Musallam
551
into [our groups. Group I includes high occurrence fungi which are isolated 10-20 times out of 20. It was represented by 16 species, 3 of which are highly osmophilic while the others are strongly osmotolerant. The members of this group are species belonging to the genera of Aspergillus, Penicillium, Alternaria, Coniothyrium, Stachybotrys, Myrothecium, Fusarium, and Cephalosporium. Group II consists of moderate occurrence fungi (isolated 6-9 times) and represented by twelve species, the majority of which arc also strongly osmotolerant. It contains some species of Aspergillus, Penicillium,Fusarium, Drechslera, Ulocladium, and Chaetomium. Group III contains low occurrence fungi (isolated 3-5 times), that comprised sixteen species, some of which are strongly while the others are weakly osmotolerant. In group IV are placed those species of rare occurrence, which are isolated less than three times (not included in Table 2). Most of the members included in this group are weak osmotolerants. It comprised Penicillium lanosum, Petriellidium desertorum, Microascus trigonosporus, Emericellopsis glabra, Myxotrichum deflexum, Scopulariopsis brevicaulis, S. candida, Tritirachium album, Fusariella opstipa, Memnoniella echinata, Camarosporium aequivocum, Pleospora infectoria, Fusarium solani, Cladosporium herbarum, Mucor circinelloides, Pseudodiplodia sp., Rhizopus stolonifer, R. arrhizus, Cunninghamella sp., Stemphylium botryosum, Hendersonia sp., Phialophora sp., Sepedonium sp., Pithomyces maydicus, Thermoyces lanuginosus, and Sporotrichum thermophile.
Osmophilic and osmotolerant species To differentiate between osmophilic and osmotolerant species among all the isolated organisms in this investigation, their spores or mycelial fragments were inoculated on Czapek's agar supplemented with various concentrations of sucrose, 10, 20, 40, and 60 %. The colony diameters were measured and compared. From the results three major groups were recognized (Table 2). A, highly osmophilic; consists of fungi showing their best growth at 60 %. This group includes only three species namely Aspergillus repens, A. amstelodami, and A. restrictus. B, Strong osmotolerant; represented by thirty-eight species, constituting the major part of the recovered species. This group contains those organisms which showed their best growth at 20 or 40 %, but were also capable of making a reasonable amount of growth at 60 %. C, Weak osmotolerant; includes those fungi which showed their maximum growth at IO or 3 % (control) and might also grow at 20 or 40 %, but failed completely to grow at 60 %. This last group was represented by fifteen species, most of which were infrequently isolated. DISCUSSION
The main features of the mycoflora inhabiting saline soils was the preponderance of a limited number of genera and species as compared to normal soils (Bayliss Elliot, 1930; Saito, 1952; Pugh, 1962). This may be an effect of high pH (Jensen, 193I), and poor aeration resulting from the regular flooding of these soils by sea water (Pugh, 1962). Since the total count of soil fungi fluctuates, in response to the method employed for isolation of soil fungi as well as to any slight variation in the
552
Transactions British Mycological Society
chemical, physical, and ecological conditions, it was more suitable to rely on the frequency of occurrence (number of isolations) offungal individuals rather than on the total counts of these fungi (Moubasher & Moustafa, 1970). . In the present work, a total of 82 species belonging to 44 genera were collected. The most frequent species were those belonging to the genera; Aspergillus, Penicillium, Fusarium, Alternaria, Myrothecium, Cephalosporium, Coniothyrium and Stachybotrys. Most of those fungi are strong osmotolerants. A very similar order of dominance was also observed by Sparrow (1937), Stover (1955), Domsch (1960), Griffin (1963), and Chen (1964) who attributed the abundance of those fungi to their ability to thrive at low oxygen tensions, and limited water activities. The term osmophilous fungi is used in a general sense referring to fungi growing better on media containing high sugar concentrations. These osmophilous species which are easily missed in most routine isolation work, as they are frequently overgrown by fast growing fungi, could be isolated in higher frequencies of occurrence (but not necessarily in higher counts) when the isolation media are amended by higher concentrations of sugar or salt. The employment of these high concentrations gives these fungi a better chance to germinate freely and give rise to colonies, since at such higher osmotic pressures few fungi could develop, with a smaller degree of competition. Thirty-four osmophilous species (Table 2, second column) were recovered from plates of Czapek's agar supplemented with 40 % sucrose as recommended by Hudson (1972). During this work four main observations were noted. First, most of those osmophilous species were also recorded on normal Czapek's (3 %) with more or less similar frequency of occurrence. Secondly, some few species like Aspergillus repens and A. amstelodami, which were not seen on isolation plates with normal Czapek's, were encountered with high frequency of occurrence in high osmotic media. Thirdly, some fungi showed a marked increase in their frequency of occurrence on 40 % sucrose compared with 3 %. This trend was well indicated by Aspergillus niger, A. fumigatus, Ulocladium consortiale, and Chaetomium olivaceum. However, some others showed the opposite trend, i.e. either recorded in lower frequency or failed to develop and accordingly not recorded on 40 % sucrose. Fourthly, when all the fungi isolated during this investigation were grown on various concentrations of sucrose, from 3 to 60 %, very few species proved to be highly osmophilic while the other species showed various degrees of osmotolerance. These observations indicate that the mycoflora of saline soils does not only consist of osmophilic species but also contains other species with varying degrees of osmotolerance. The authors are most grateful to all the members of the C.M.I., Kew, England, and C.B.S. Baarn, Holland, for their kind help in checking the identifications of several species reported in this investigation.
Kuwait fungi. A. F. Moustafa and A. A. Al-Musallam
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(Acceptedfor publication
21
April 1975)