IANKESTERIANA2 23-30 2001


 ENDOPHYTES OF SERAPIAS PARVIFLORA PARL.
 AND SPIRANTHES SPIRALIS (L.) CHEVALL. (ORCHIDACEAE):
DESCRIPTION OF ENDOPHYTES OF S. PARVIFLORA, AND IN VITRO
 SYMBIOSIS DEVELOPMENT IN S. PARVIFLORA
 AND SPIRANTHES SPIRALIS


 PIER LUIGI PACETTI and SABINE RIESS

 Dipartimento di Scienze Ambientali, Universita della Tuscia, 1-01100 Viterbo, Italy

ABSTRACT. Endophytes were isolated from Serapias parviflora (Orchidaceae) roots. They are
described and partially classified under microscope, after growth on PDA. Two fungi had symbiotic
characters: A-Sepa-1, an ascomycete, and B-Sepa-1, a basidiomycete. At the same time, many plants
of S. parviflora and Spiranthes spiralis were asymbiotically obtained by sterilisation of seeds and
sowing on modified Frosch medium. After transplantation to symbiotic medium (modified Basic
Oats), they were inoculated with isolated fungi. Serapias parviflora was used as control and S. spi -
ralis was used to establish specificity between hosts and endophytes. The two fungi were able to
induce symbiosis in S. I 9., i .... in vitro, while only B-Sepa-1 induced symbiosis in S. spiralis
roots in vitro. We conclude that specificity between these fungi and the two orchid species studied
in vitro is different, possibly substantiating the hypothesis of a potential and ecological specificity.

RESUMEN. Hongos end6fitos fueron aislados de raices de Serapias parviflora (Orchidaceae). Fueron
descritos y clasificados parcialmente bajo el microscopio de luz luego de ser cultivados en PDA.
Dos de ellos presentaron caracteristicas de simbiontes: la Cepa-A-1, un ascomicete, y la Cepa-B-1,
un basidiomicete. Al mismo tiempo muchas plants de S. parviflora y Spiranthes spiralis fueron
obtenidas asimbi6ticamente por esterilizaci6n de semillas y cultivo en un medio Frosch modificado.
Luego de transplantarlas a un medio simbi6tico (Oats modificado), las plants fueron inoculadas con
los hongos aislados. Serapias parviflora fue utilizada como control y S. spiralis lo fue para estable-
cer especificidad entire hospederos y end6fitos. Los dos hongos fueron capaces de inducir simbiosis
in vitro en raices de S. parviflora, mientras que solo la Cepa-B-1 indujo simbiosis in vitro en raices
de S. spiralis. Concluimos que la especificidad in vitro entire estos hongos y las dos species de
orquideas estudiadas es diferente, posiblemente apoyando la hip6tesis de una especificidad ecol6gi-
ca potential.

KEY WORDS: Orchidaceae, Serapias parviflora, Spiranthes spiralis, symbiotic fungi, endophytes,
Italy.


 Introduction. Orchids need endomycorrhizae to
develop: green orchids need fungi for the early
developmental stages, while orchids lacking
chlorophyll are always completely dependent upon
fungi. Endophytes of orchids are always Mitosporic
Fungi. Three classes are recognized in this group:
Hyphomycetes, Coelomycetes, and Agonomycetes.
To the latter class belong sterile fungi that may pro-
duce chlamydospores or sclerotia and the genus
Rhizoctonia DC., whose members may also


produce sclerotia. Most orchid endophytes are
ascribed to this group. Only few traits were used to
describe this genus (Curtis 1937) but unfortunately
they have no taxonomic value since they do not
allow discrimination between very similar
Rhizoctonia species with very different perfect
states. Rambelli (1981) suggested the presence of
dolipores or clamp connections as a character to
assign a fungus to the basidiomycetes when
reproductive structures are absent. Moreover, Riess