GRAPHIS ScnIPTA

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l0 Marko Hycirinen and Peter D. Crittenden potential surface contaminants, this step wuls repeated (W2), and then the exchangeable cations eluted by two 30 min treatments in l0 ml 20 mM NiCl2 Ni l, Ni2) prior to a final l0 min wash by submerging in a further l0 ml water (W3). The submerged thalli were shaken gently during each step in the procedure. The average net change in volume of solution in a vial due to carry over with the lichen sample from one vial to another was estimated by weighing a subsample of 5 vials at each step before and after elution. Subsequent concentration calculations were based on these corrected volumes. After the final elution thalli were then digested in concentrated HNO3 and the digest evaporated to dryness at 175 "C, The residue was dissolved in l0 ml I M HNO3 and appropriate quantities of CsCl2 and LaCl2 added prior to the determination of K*, Mg'* and Ca2* in the water washes, Ni solutions and acid digests by means of atomic absorption spectrophotometry (AAS) using acetylene as fuel. Air was used as support gas in K* and Mg2* analyses and nitrous oxide in Ct* analysis. Flame emission mode was used for Mg2* and atomic absorption mode for the other two elements. Extracellular cation concentrations were derived from analysis of Ni I and Ni2 and intracellular concentrations from analysis of the acid digests. Results and discussion The results showed that somewhat surprisingly the cellular distribution of cations was fairly similar between the fresh and stored material (Figure I ). No significant differences between concentrations of intracellular or extracellular cations in fresh and stored thalli were observed although the variations in content of extracellular K* and in the ratio extracellular: intracellular K* were significantly GRAPHTS SCRTPTA 12 (2000) greater in stored thalli (F,**-test, p
GRAPHTS SCRTPTA 12 (2000) Cations in Cladonia portentosa I I ?60 do o l- it 40 Intracellular I Extracellular f-] F resh Stored Fresh Stored Fresh Stored K- Mgt* c** A 204 -ao tr E{J. v -- + l) llo C) € ?. H ct + r^ "to LV Figure 1. Mean concentrations of inta- and extracellular K*, tvtg2* and Ca2* in the apices of 6 months stored and freshly collectd Cladonia portentosa (1 I S.D., n = 9 in both batches). Hyv[rinen, M. & Crittenden, P. D. 1996: Nieboer, E., Richardson, D. H. S. & Tomas- Cation ratios in Cladonia portenbsa as sini, F. D. 1978: Mineral uptake and indicesofprecipitationacidityintheBrit- release by lichens: an overview. Bryoloish Isles. New Phytologist Ii2: 521-532. gist 8l:226-246.
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Page 3 and 4: On the identity of Ocellularia atla
Page 5 and 6: The lichens on gneiss and diabase o
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Page 11: Influence of air-drying and storage
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Page 17 and 18: Moelleropsis nebulosa rediscovered
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Page 21 and 22: Eopyrenula septemseptata new to Swe
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Page 29 and 30: GRAPHTS SCRTPTA 12 (2000) Cetraria
Page 31 and 32: Nya lavfynd frfln Halland och Smila
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