Mycorrhizae in Hawaiian Epiphytes!

Home , Gemma (botany), Psilotum complanatum

2 J. N. GEMMA AND R. E. KOSKE

ABSTRACT: In surveys in the Hawaiian Islands, mycorrhizae occurred fre quently in epiphytic, nonorchidaceous angiosperms and pteridophytes. Both vesicular-arbuscular (VA) and ericoid mycorrhizae were present in epiphytes growing 1-3 m above the forest floor on dead and living tree trunks and on living tree ferns in montane wet forest sites. All eight angiosperm species were mycorrhizal, and 13 of 22 pteridophytes possessed VA mycorrhizae. The high frequency of mycorrhizae in epiphytic species suggests that propagules of my corrhizal fungi routinely are dispersed to these microsites. Possible means of dispersal are discussed.

IN THE MONTANE WET forests ofthe Hawaiian June 1990. Roots of the epiphytes typically Islands a dense epiphytic flora ofangiosperms were growing in thick mats of moss that and pteridophytes flourishes. Intensive studies covered the trunks. Sampled plants were at of Hawaiian angiosperms and pteridophytes tached to their substrate at elevations of 1-3 growing in a variety of habitats (Gemma m above ground level. Care was taken during et al. 1992, Koske et al. 1992) revealed that collecting to sample individual plants for a high percentage of these species form ve which roots could be positively identified as sicular-arbuscular mycorrhizae (VAM). In belonging to the particular plant. Most col those surveys mycorrhizae were found to be lections were made in the Koke'e and Alaka'i common among the epiphytes. Because VA Swamp areas (Koke'e State Park) at eleva and ericoid mycorrhizae seldom are reported tions of ca. 1100 m above sea level on the is to occur in epiphytic, nonorchidaceous an land of Kaua'i. A few samples were collected giosperms and pteridophytes (Boullard 1957, from similar sites on the islands of Maui and Cooper 1976, Nadkami 1981, Berch and Moloka'i. Kendrick 1982, Trappe 1987, Lesica and Roots were preserved in 50% isopropyl Antibus 1990, Maffia et al. 1990), we were alcohol and later were cleared in hot 2.5% prompted to sample a greater diversity of KOH and stained with 0.05% trypan blue in species to better assess the prevalence of an acidified glycerol solution (Koske and mycotrophy among Hawaiian epiphytes. Gemma 1989). Stained roots were mounted on slides in a polyvinyl alcohol-based solu tion (PVLG) (Koske and Tessier 1983). En tire root systems were examined at 40-60 x MATERIALS AND METHODS with a dissecting microscope, and portions of Root samples (10-40 cm long) were col each root system were examined at 400 x lected from plants growing on living and with a compound microscope. The presence dead trunks of trees (mostly of Metrosideros of vesicles, arbuscules, hyphal coils, and in polymorpha Gaud.) and tree ferns (Cibotium ternal hyphae was noted for each specimen. glaucum [J. E. Sm.]" Hook. & Amott) in Only those species in which arbuscules were montane wet forests between July 1987 and found were considered to have functional VAM. ExtenlqfYAM jI1f~ctj()!1 \V~~ _gl.tanti fiedhy asSigning a mycorrhizal index (MI) value of 0-3 to stained root samples, where 0 1 Manuscript accepted 28 March 1994. 2 Department of Botany, University of Rhode Island, indicates no VAM infection, 1 = up to 25% Kingston, Rhode Island 02881. of root length infected (i.e., containing any 175 176 PACIFIC SCIENCE, Volume 49, April 1995 combination of the VAM fungal structures fern species examined (Tables 1, 2). Among listed above), 2 = 25-50% infected, and 3 = the angiosperms, a high MI was recorded > 50% infected. The MI of each species was for Astelia menziesiana Sm., Cheirodendron calculated by averaging the MI of each sam sp., Coprosma kauensis (A. Gray) A. Heller, ple of the species examined. Dianella sandwicensis Hook. & Amott, M. Differences between intensity of infection polymorpha, and Peperomia hesperomannii of Anthophyta and Pterophyta were ana Wawra (Table 2). All 13 samples of M. lyzed using a t test, and differences in polymorpha were densely colonized by VAM incidence of mycorrhizae in members of fungi. Both VA and ericoid mycorrhizae were the two groups were assessed using the chi present in all collections of Vaccinium calyci square test, adjusted for small sample size. num Sm. and Styphelia tameiameiae (Cham. & For both tests,significance was indicated Schlee.) F. v. Muell., members of families when P < 0.05. whose members typically form only ericoid When ericoid mycorrhizae were found in mycorrhizae (Harley and Smith 1983). VAM roots, their presence was noted, but no rating previously have been reported to occur in of intensity of infection was assigned. these two species in Hawai'i (Koske et al. Voucher slides of roots have been pre 1990). served in the authors' collection. Voucher Among the pteridophytes, Vittaria elon specimens ofmost plant materials are lodged gata Sw., Mecodium recurvum (Gaud.) Co in the herbarium at the National Tropical pel., Elaphoglossum aemulum (Kaulf.) Brack, Botanical Garden, Uiwa'i, Kaua'i. Nomen and E. crassifolium (Gaud.) Anderson & clature for angiosperms is based on Wagner Crosby had the highest MI values (Table 2). et al. (1990) and for pteridophytes on Wagner Rhizome scales of E. wawrae (Luerss.) C. (1981) and Takhtajan (1986). Some data for Chr. often contained hyphae and vesicles the pteridophytes that are included in the re of VAM fungi. Mycorrhizae were present in sults section have been reported previously the epiphytic lycopod Huperzia phyllantha (Gemma et al. 1992). They are cited here for (Hook. & Amott) Holub. and absent from completeness. Psi/otum complanatum Sw. The average MI of all specimens was sig nificantly higher for the angiosperms (2.3) than for the pteridophytes (1.1), as was the RESULTS AND DISCUSSION frequency of mycorrhizae in the specimens VAM occurred in 62 ofthe 91 root systems examined (Table 1). Mycorrhizae were more examined. They were present in every angio common in the endemic species (18 of 23) sperm specimen examined (31 samples en than in the indigenous species (three of compassing eight species) and in 13 of the 22 seven), but the difference was not significant.

TABLE 1

SUMMARY OF OCCURRENCE OF MYCORRHIZAE IN HAWAllAN EpIPHYTES

PARAMETERS ANTHOPHYTA PfEROPHYTAa TOTAL

No. species examined 8 22 30 No. species mycorrhizalb 8a 13a 21 Average MI of species' 2.3a (±0.6) 1.1b (± 1.1) 1.6 (± 1.1) No. specimens examined 31 60 91 No. specimens mycorrhizal 3la 31b 62

aAlso includes Lycopodophyta and Psilophyta. bVA and ericoid mycorrhizae; values in rows followed by the same letter did not differ significantly (P = 0.05). 'MI, mycorrhizal index (see text). SD in parentheses.

iJlii&& !'dlW'IP,npsNl$i W,@,! @§iPM. iiiM£i@ m • TABLE 2

MYCORRffiZAE IN HAWAllAN EpIPHYTES

o TAXA M/n MI' STATUS'

Anthophyta Araliaceae Cheirodendron sp. 1/1 3.0 E Epacridaceae Styphelia tameiameiae (Cham. & Schlee.) F. v. Muell. 2/2d 1.5 Ericaceae Vaccinium calycinum Sm. 2/2d 1.5 E Liliaceae Astelia menziesiana Sm. 5/5 3.0 E Dianel/a sandwicensis Hook. & Arnott 2/2 2.5 E Myrtaceae Metrosideros polymorpha Gaud. B/B 23 E Piperaceae Peperomia hesperomannii Wawra 4/4 2.3 E Rubiaceae Coprosma kauensis (A. Gray) A. Heller 2/2 2.5 E Psilophyta Psilotaceae Psilotum complanatum Sw. 2/0 0 Lycopodophyta Lycopodiaceae Huperzia phyl/antha (Hook. & Arnott) Holub. 1/1 1.0 E Pterophyta Ophioglossaceae Ophioglossum pendulum L. 3/4 2.3 Vittariaceae Vittaria elongata Sw. 2/2 3.0 Gramittidaceae Adenophorus abietinus (D.c. Eaton) K. A. Wilson 1/2 1.5 E A. pinnatifidus Gaud. 0/3 0 E A. tamariscinus (Kaulf.) Hook & Grev. 4/5 1.2 E Grammitis tenel/a Kaulf. 1/5 0.4 E G. baldwinii (Baker) Copel. 0/1 0 E Xiphiopteris saffordii (Maxon) Copel. 0/2 0 E Polypodiaceae Pleopeltis thundbergiana Kaulf. 0/1 0 Hymenophyllaceae Mecodium recurvum (Gaud.) Copel. 2/2 3.0 E Sphaerocionium lanceolatum (Hook. & Arnott) Copel. 3/5 1.0 E Vandenboscia daval/iodes (Gaud.) Copel. 0/1 0 E V. cyrtotheca (Hillebr.) Copel. 0/1 0 E Aspleniacae Asplenium nidus L. 0/1 0 Elaphoglossaceae Elaphoglossum aemulum (Kaulf.) Brack 4/4 2.5 E E. alatum Gaud. 3/4 1.2 E E. crassifolium (Gaud.) Anderson & Crosby 2/2 3.0 E E. hirtum (Sw.) C. Chr. 0/4 0 I E. pel/ucidum Gaud. 2/3 0.9 E E. wawrae (Luerss.) C. Chr. 2/3 1.7 E

a M, no. of specimens with vesicular-arbuscular mycorrhizae; n, no. of specimens examined. 'MI, average mycorrhizal index for the species (see text). eE, endemic; I, indigenous. d All specimens bore both ericoid and VA mycorrhizae. 178 PACIFIC SCIENCE, Volume 49, April 1995

The frequent occurrence of VAM in Ha thought to be rare or absent in epiphytic waiian epiphytes suggests that the fungi are pteridophytes (Boullard 1957, Cooper 1976, easily dispersed to the mossy mats that blan Berch and Kendrick 1982). The mycorrhizal ket the dead and living vegetation. Elevation status of epiphytic ferns and nonorchida of the substrate above the soil surface did not ceous angiosperms in tropical sites has only appear to correlate with MI, and MI values recently received much attention (Trappe of 3.0 were recorded from specimens col 1987, Lesica and Antibus 1990, Maffia et lected at all sampling heights. al. 1990). Of 12 species of epiphytic pter The means by which propagules of my idophytes examined in Costa Rican rain corrhizal fungi reach epiphytic habitats are forests, none was mycorrhizal (Lesica and not known. However, Hawaiian birds collect Antibus 1990). In that same survey, of 56 and transport fern rhizomes and roots, angiosperm species, only eight formed VAM, mosses, and other plant materials for nest four formed ericoid mycorrhizae, and six of building (van Riper and Scott 1979, Carl the 14 orchid species were mycorrhizal. quist 1980). Because propagules of VAM Similar findings were reported from another fungi (e.g., hyphae, vesicles, spores) may be Costa Rican site by Maffia et al. (1990). found on or in such nesting material and in The Costa Rican results are in sharp con adherent soil (parke and Linderman 1980, trast to the findings of our survey, and the Gemma and Koske 1990, Gemma et al. 1992), differences may reflect the unusual bioge it is possible that birds disperse the fungi to ography and flora of the Hawaiian Islands habitats suitable for epiphytic plants. Other (Carlquist 1974, Wagner et al. 1990, Gemma animals (e.g., arthropods and small mam et al. 1992, Koske et al. 1992). However, not mals) also may be similarly involved in all non-Hawaiian epiphytic sites are charac transport of the fungi (Mcllveen and Cole terized by the absence or infrequency of my 1976, Trappe and Maser 1976, Rabatin and corrhizae. Epiphytic bromeliad species from Stinner 1988). South America are routinely mycorrhizal At a potential epiphytic microsite, plant (S. Rabatin, pers. comm.). and fungus could arrive independently of Information on the mycorrhizal status of each other or may co-disperse (Koske and endemic Hawaiian epiphytes may be valua Gemma 1990). The latter would result if a ble in attempts to propagate these species vegetative fragment of a plant (e.g., a rhi in greenhouse conditions. With nearly 40% zome) or a young seedling/sporophyte bear of the native angiosperm flora of Hawai'i ing mycorrhizal fungi were deposited at a threatened or endangered to some degree site. As the young plant began to grow, (Wagner et al. 1990), temporary conservation newly formed roots would become infected in botanical gardens may be necessary with mycorrhizal fungi growing from old (Theobald 1989). Because standard green roots or from soil adhering to the plant. Such house practices (e.g., sterile soilless mixes, co-dispersal has been documented in rhizo fungicides, and heavy fertilization) routinely matous species that are primary colonizers of exclude or inhibit VAM fungi, it may be sand dunes (Gemma and Koske 1989, Koske necessary to modify cultivation methods to and Gemma 1990). encourage the fungi for those plant species The high frequency of mycorrhizae in the that are obligate mycotrophs (Gemma and collections indicates that VAM fungi are Koske 1988). constant, predictable inhabitants of the epi phytic community in Hawaiian wet forests. Similar results were observed among terres- ACKNOWLEDGMENTS . tJ:i~l §P~fi~ iIlI!a~!li'i, wh~I"~?".?_QY~ ",r ~1l~ angiosperms and 75% of the pteridophytes We thank Tim Flyim and Dave Lorence were mycorrhizal (Gemma et al. 1992, Koske for assistance in collecting and identifying the et al. 1992). plants and an anonymous reviewer for help Until now, VAM generally have been ful comments.

9",01 Ii uwguRMi'Mit!W# t WW&lkiiQa,&"W'¥&¥,*44 Mycorrhizae in Hawaiian Epiphytes-GEMMA AND KOSKE 179

LITERATURE CITED KOSKE, R. E., and B. TESSIER. 1983. A con venient, permanent slide mounting me BERCH, S. M., and N. KENDRICK. 1982. Ve dium. Mycol. Soc. Am. News!. 34(2): 59. sicular-arbuscular mycorrhizae ofsouthern LESICA, P., and R. K. ANTmus. 1990. The Ontario ferns and fern allies. Mycologia occurrence of mycorrhizae in vascular 74: 769-776. epiphytes of two Costa Rican rain forests. BOULLARD, B. 1957. La mycotrophie chezes Biotropica 22: 250-258. Pteridophyte. Sa frequence, ses caracteres, MAFFIA, B., N. M. NADKARNI, and D. P. sa signification. Botaniste 41 : 5-15. JANOS. 1990. Mycorrhizae of ephiphytic CARLQUIST, S. 1974. Island biology. Colum and terrestrial Piperaceae in a tropical bia University Press, New York. montane cloud forest in Costa Rica. Page ---. 1980. Hawaii: A natural history, 123 in M. F. Allen and S. E. Williams, 2nd ed. Pacific Tropical Botanical Gar eds. Abstracts of 8th North American den, Uiwa'i, Hawai'i. Conference on Mycorrhizae, Jackson, COOPER, K. M. 1976. A field survey of my Wyoming, 5-8 September 1990. Uni corrhizas in New Zealand ferns. N. Z. J. versity of Wyoming, Agricultural Experi Bot. 14: 169-181. ment Station, Laramie. GEMMA, J. N., and R. E. KOSKE. 1988. Plant McILVEEN, W. D., and H. COLE. 1976. Spore fungus symbiosis may aid conservation of dispersal ofEndogonaceae by worms, ants, the Hawaiian flora. Bull. Pac. Trop. Bot. wasps, and birds. Can. J. Bot. 54: 1486 Gard. 18(2-3): 38-41. 1489. ---. 1989. Field inoculation of American NADKARNI, N. M. 1981. Canopy roots: Con beachgrass (Ammophila breviligulata) with vergent evolution in rainforest nutrient VA mycorrhizal fungi. J. Environ. Man cycles. Science (Washington, D.C.) 214: age. 29: 173-182. 1023-1024. ---. 1990. Mycorrhizae in recent volcanic PARKE, J. L., and R. G. LINDERMAN. 1980. substrates in Hawaii. Am. J. Bot. 77: Association of vesicular-arbuscular my 1193-1200. corrhizal fungi with the moss Funaria hy GEMMA, J. N., R. E. KOSKE, and T. FLYNN. gometrica. Can. J. Bot. 58: 1898-1904. 1992. Mycorrhizae in Hawaiian pter RABATIN, S. c., and B. R. STINNER. 1988. idophytes: Occurrence and evolutionary Indirect effects of interactions between significance. Am. J. Bot. 79: 843-852. VAM fungi and soil-inhabiting inverte HARLEY, J. L., and S. E. Smith. 1983. My brates on plant processes. Agric. Ecosyst. corrhizal symbiosis. Academic Press, Environ. 24: 135-146. London. TAKHTAJAN, A. 1986. Floristic regions of the KOSKE, R. E., and J. N. GEMMA. 1989. A world. University of California Press, modified procedure for staining roots to Berkeley. detect V-A mycorrhizas. Mycol. Res. 92: THEOBALD, W. L. 1989. Botanic gardens for 486-488. plant conservation. Pages 55-59 in C. P. ---. 1990. VA mycorrhizae in strand Stone and D. B. Stone, eds. Conservation vegetation of Hawaii: Evidence for long biology in Hawaii. Cooperative National distance codispersal of plants and fungi. Park Resources Study Unit, University of Am. J. Bot. 77:466-474. Hawai'i, Honolulu. KOSKE, R. E., J. N. GEMMA, and L. ENG TRApPE, J. M. 1987. Phylogenetic and eco LANDER. 1990. Vesicular arbuscular my logic aspects of mycotrophy in the angio corrhizae in Hawaiian Ericales. Am. J. sperms from an evolutionary standpoint. Bot. 77: 64-68. Pages 5-26 in G. R. Safir, ed. Ecophys KosKE, R. Eo, J. N. GEMMA, and T. FLYNN. lology of VA. mycorrmzaf pTants. eRe 1992. Mycorrhizae in Hawaiian angio Press, Boca Raton, Florida. sperms: Occurrence and evolutionary sig TRApPE, J. M., and C. MASER. 1976. Germi nificance. Am. J. Bot. 79: 853-862. nation of spores of Glomus macrocarpus 180 PACIFIC SCIENCE, Volume 49, April 1995

(Endogonaceae) after passage through a WAGNER, W. H. 1981. Fernsin the Hawaiian rodent digestive tract. Mycologia 68: 433 Islands. Fiddlehead Forum (Bull. Am. 436. Fern Soc.) 8: 43-44. VAN RIPER, c., and J. M. SCOTT. 1979. Ob WAGNER, W. L., D. R. HERBST, and S. H. servations on distribution, diet, and breed SOHMER. 1990. Manual of the flowering ing of the Hawaiian thrush. Condor 81: plants of Hawai'i. University of Hawai'i 65-71. Press and Bishop Museum Press, Honolulu.

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