University of Groningen
The mutual relations between algae and fungi in lichens
Quispel, Anton
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1943
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Quispel, A. (1943). The mutual relations between algae and fungi in lichens Groningen: s.n.
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inly is formed by the provision
' I only have to remind of the
rt the specificinfluence of the
availabilityof "vandophytin ".
: as follows;
uhereaital units are dependent
t hasa mutualisticor a parasitic
,io- or a heterosymbiosis)this
with the exchangeof nutrilites.
SUMMARY.
The fungi which live in symbiosis with the aerial proto-pleurococcoid algae were isolated in pure culture. It appearedthat
there existed a great similarity between the morphological
charactersof these fungi and true lichen fungi. Yet the growthvelocity was much better. In consequencethey formed an
excellent object for the study of the symbiosis.
2 . It appearedthat these fungi could develop on media containing
sugars, polyalcohols or starch, that some of them could use
peptonesas sourcesof carbon. Celluloseand pectin were not
attacked,nor were salts of organic acids.
3 . The fungi could not fix atmospheric nitrogen, there was no
preference for organic sources of nitrogen over ammonium
salts.
4 . They could not developin pure synthetic culture solutions,the
addition of somenutrilites wasabsolutelyindispensable.
Partially
these nutrilites could be identified with aneurin and B alanin.
5 . The symbionticalgae(Apatococcusand a number of Cystococcus
gonidia) can provide these nutrilites (or similar) to the fungi.
6. The fungus of Xanthoria parietina showed the same need of
some nutrilites. It appeared that these nutrilites belonged to
the bios group.
,7
The Cystococcusgonidia of Xanthoria parierina, Physcia pulverulenta and Parmelia acetabulumgrew much better on organic
substratesthan on inorganic media. \il7henthe inoculation was
not too heavy, after three months not a trace of development
could be observed in culture solutions without organic substances.Simple carbohydrateswere the best sourcesof carbon:
there wa, ,ro'maiked pt".fèi.".. for org."i. rónt..t of .rit-g.nl
There was no reason to suppose any fixing of atmospheric
nitrogen.
8 . The heterotrophic development of these gonidia was favoured
by the addition of extracts from the symbiontic fungi but also
by the addition of yeast-extract.These extracts were not abso_lutelynecessary,their only influence consistedof a shortening
of the lag-phasein growth. The active factors of theseextracté
partially belonged to the bios-group, in some casesnicotinic
acid had a marked influence. Partially the effect might have
I.
34*
532
been caused by the presenceof suitable sourcesof nitrogen.
9. The autotrophic developmentonly was possible(or was highly
stimulated)by the presenceof ascorbic acid, dioxymaleic acid
and (most probably still) by other dienolic compounds.(glucoreducton). As these substancesare easily oxidrzed by the air
the effect was most pronounced, when the cultures were incubatedin an atmosphereof hydrogen with 5 f" carbon-droxyde
in the light. Then only rooy or( ascorbic acid gave a development, which was comparable to the development on organic
culture solutions.
ro. Upon these facts a mutualistic theory of the symbiosis was
based, in which apart from the provision with assimilation
substancesof the fungus by the algaethe exchangeof nutrilites
played an important role.
rr. A new method for the synthesisof the symbiosisis described,
which makes it possible to changethe humidity and the concentration of the food-substancesat will.
12. The fungi which live in symbiosis with the proto-pleurococcoid
algaecould produceno lichenic acidsor similar substances,
when
cultivated under the most varying circumstances.
13. On the other hand it appearedthat the alga Apatococcusminor
synthesizesa remarkablemetabolicproduct provisionally named
apatococcrn.
14. A chemicalinvestigationof this substanceshowedthat it possessesthe following tentative formula CrrHorOnN,that it possesses
one carboxylic group esterified with methanol or ethanol, that
it most probably possesses
a long paraffin chain. The function
of the nitrogen could not be elucidated, the neutral character
of the substancemade probable, that the basic function of this
nitrogen was anyhow bound by an acid group of the molecule.
A relationship with certain aliphatic lichenic acids is probable.
rj. The literature concerning the problem of the production of
lichenic acids is reviewed and it was concluded that as certain
fungi can produce certain lichenic acids, and certain algae can
produce similar substancesin pure culture the lichenic acids
cannot be regardedas the result of a specific metabolismof the
symbiosis.We haveonly the right to speakabout an accumulation
of these substancesas a result of the symbiosis in some cases.
t6. The water-householdof the Cystococcusgonidia in pure culture
was examined; it appearedthat these algaemost probably can
endure the desiccation on the natural substrates of lichen s
without the protection of the fungus. After a week drying over
concentratedsulphuric acid, they had not lost their vitality,
t
533
f suitablesourcesof nitrogen.
ly waspossible(or was highly
;corbicacid, dioxymaleicacid
:r dienoliccompounds.(glucotre easily oxidrzed by the air
, when the cultures were inrgenwith 5 fo carbon-droxyde
ascorbicacid gave a developthe developmenton organic
theory of the symbiosis was
: provision with assimilation
lgaethe exchangeof nutrilites
of the symbiosisis described,
Ie the humidity and the cons at will.
; with the proto-pleurococcoid
idsor similarsubstances,
when
rg circumstances.
rt the algaApatococcusminor
c productprovisionallynamed
bstanceshowedthat it possesa CrrHnrQN,that it possesses
rith methanol or ethanol, that
paraffin chain. The function
cidated,the neutral character
rhatthe basic function of this
n acid group of the molecule.
rtic lichenic acids is probable.
roblem of the production of
wasconcludedthat as certain
c acids,and certain algaecan
rre culture the lichenic acids
f a specificmetabolism of the
:ospeakaboutan accumulation
the symbiosisin some cases.
coccusgonidiain pure culture
resealgaemost probably can
ratural substratesof lichen s
;us.After a week drying over
t had not lost their vitalitv'
in a relative humidity of the atmosphere
F.y could develop
higher than 9r oÁ, while high remperarures only could be
endured, when the relative humiditv was low.
1 7 . There is only little difference between the imbibition-curves of
the lichen-thallus, the lichen-fungus and the lichen-gonidia of
the same lichen-species.
r 8 . The protective influence of the fungus against desiccation of
the.algaeonly is very small and can only bè perceivedwhen the
desiccationis not too intense.
r9. The lichen-symbiosisis comparedwith orher casesof symbiosis
and it is concluded,that the differencesare only apparent,while
th_ereis a great similarity as in all other symbiósií ftre exchange
q{ nutrilites plays one of the most impoitant roles.
20. This similgrity still can be observed,when we extend the definitjon of symbiosis rowards all dependencesof vital units
belo_nging
to the sameor to different speciesashasbeenproposed
by Beas-BrcrrNc and for which definition someargumentsare
brought together in this paper.