Wanda Quilhot

EFFECTS OF SOLAR UV-B RADIATION IN THE ACCUMULATION OF RHIZOCARPIC ACID IN A LICHEN SPECIES FROM ALPINE ZONES OF CHILE

En la especie liquenica Acarospora schleicheri, recolectada en gradientes altitudinales a 18o, 19o y 33o Lat. S, en zonas alpinas de Chile, se determinaron y compararon las concentraciones de acido rizocarpico. Se observaron incrementos significativos en la acumulacion del metabolito con la altura s.n.m. y el aumento en los niveles de radiacion UV-B en los gradientes seleccionados. Los resultados obtenidos sugieren que la sintesis de acido rizocarpico es inducida por la radiacion UV-B y que su presencia representa una adaptacion quimica frente a los elevados niveles de radiacion UV-B en los habitats de esta especie liquenica.

Epiphorellic acids 1 and 2, two diaryl ethers from the lichen Cornicularia epiphorella

Abstract From the lichen Cornicularia epiphorella two new diaryl ethers, epiphorellic acids 1 and 2, were isolated besides the known compound atranorin. The structures of the new compounds were established by spectroscopic evidence and chemical transformations. The structure of epiphorellic acid 1 was also confirmed by correlation with a known compound.

Distribution and habitat ecology of the sorediate species of Menegazzia (Parmeliaceae, lichenized Ascomycota) in Chile

Recientemente se han publicado datos sobre la taxonomia y ecologia de las especies sorediosas de Menegazzia representadas en las regiones mas australes de Chile y Argentina e islas del Atlantico Sur, ademas de registros esporadicos en zonas ubicadas mas al norte en Chile. En este trabajo se discuten los patrones de distribucion y la ecologia del habitat de 11 especies sorediosas, con especial enfasis en aquellas que se desarrollan al norte de los 48o S. Menegazzia subpertusa, un epifito de arbustos esclerofilos, se registra por primera vez en America (Chile y Argentina). Menegazzia neozelandica tiene una distribucion discontinua en Chile; ha sido recolectada en Fray Jorge (Cuarta Region de Chile), Islas Juan Fernandez y en regiones costeras al sur de los 38o S. Menegazzia kawesqarica y M. tenuis son mas frecuentes en las zonas mas australes de Chile; tambien se han encontrado en habitats de altura y bajas latitudes. Se incluyen, ademas, M. chrysogaster, M. fumarprotocetrarica, M. globulifera, M. magellanica, M. norsorediata, M. sanguinascens y M. wandae. Varias especies sorediosas crecen como pioneras en sustratos jovenes. Los patrones de distribucion a lo largo de gradientes de humedad y de luz son variables. Se presentan mapas de distribucion y clave de las especies.

Effects of UV Radiation on Usnic Acid in Xanthoparmelia microspora (Müll. Arg. Hale)

An important decrease in the level of stratospheric ozone has been observed during the past decade (1), with accompanying increases in UV-B radiation (2) and some UV-A radiation (3), thus leading to probable damage to aquatic and terrestrial ecosystems (4–7). Inhabitants of terrestrial and aquatic ecosystems have developed strategies to cope with the potential stress induced by UV radiation. One of these strategies is the synthesis of photoprotector compounds derived mainly from the biosynthetic route of the polymalonate acetate (8–13). As levels of UV radiation increase, accumulation rates of some photoprotective compounds in lichen species from the Chilean Alpine zones also increase (14). Photodegradation of depsides may have accounted for the low levels of phenolics in lichens at higher elevations (15). It was observed that, in Xanthoparmelia lichens from the Alpine regions of Chile, the higher the altitude where the lichen was found, the greater amount of usnic acid it produced (16). This increase of usnic acid is the result of the lichen’s ability to adapt to radiation, which ensures its survival in extreme environmental conditions. In thalli from Xanthoparmelia oleosa collected at 4690 m no usnic acid was detected, which could be proof of the presence of a photodegradation product of usnic acid (17) but which has not been identified to date. In growth-chamber experiments lasting 1 week, thalli of Umbilicaria americana always produced smaller amounts of phenolic residue when exposed to both UV-B and UV-A radiation, compared with exposure to UV-A alone. In one field experiment exclusion of UV-B by light filtration produced significant increases in phenolic compounds. This increase occurs only during spring and autumn, when lichens are metabolically more active (18). In this article we evaluated the accumulation rates of usnic acid in Xanthoparmelia microspora (Mull. Arg. Hale) exposed to doses of solar radiation and to additional doses of UV-A and UV-B radiation. Furthermore, we report on the photolysis of usnic acid in nonnucleofilic solvents during exposure to higher doses of UV-A and UV-B radiation.

Liqúenes de Aisén, sur de Chile

The lichen mycobiota of Aisen (southern Chile) comprises 319 taxa in 87 genera. All of the species of Menegazzia and Protousnea, previously recorded in Chile, are present in this region. The diversity of biomes, from temperate rainforests −particularly in oceanic zones− to steppe areas, offers an enormous number of macro and microhabitats favorable for lichens. The highest lichen diversity, 56 %, was recorded in an undisturbed locality in Laguna San Rafael National Park. Lichen species diversity is higher in oceanic temperate rainforests than in steppe areas, where the majority of Antarctic lichens (23 %) are registered. Levels of endemism are rather high (26 %) and are due mainly to species of the genera Protousnea, Pseudocyphellaria, Menegazzia, Cladonia, Sticta, Nephroma. Other biogeographical elements in the region’s lichen mycobiota are: cosmopolitan (16 %), austral (16 %) and bipolar (13 %). Lichen diversity in Aisen represents about 20 % of the known lichen mycobiota of Chile.

A new species of Placopsis ( Agyriaceae : Ascomycota) from Antarctica

Placopsis antarctica, which is apparently endemic to antarctic regions south of lat. 60°S (South Orkney Is, South Shetland Is and the Antarctic Peninsula), is described. Details of its morphology, anatomy, chemistry, ecology and distribution are given. Placopsis bicolor is newly reported from South Georgia. A revised key to species of Placopsis occurring in South Georgia and Antarctica is given.

Estudio preliminar de la flora liquénica de Isla Mocha, sur de Chile

La micobiota liquenizada de Isla Mocha, sur de Chile, esta representada por 76 especies en 30 generos; el 38 % de las especies son endemicas del sur de Sudamerica. Xanthoria parietina, registrada en todas las zonas de muestreo, y Pseudocyphellaria malmeana recolectada solo en el bosque de Aextoxicon punctatum, son las especies mas representativas. Ramalina fastigiata constituye un nuevo registro para Chile.

PHENOLICS, DEPSIDES AND TRITERPENES FROM THE CHILEAN LICHEN PSEUDOCYPHELLARIA NUDATA (ZAHLBR.) D.J. GALLOWAY

The lichen Pseudocyphellaria nudata is a species endemic to southern South America. From the lichen tallus, methyl orsellinate, 2-methoxy-3,6-dimethyl4-hydroxybenzaldehyde, methyl-evernate, tenuiorin, hopan-6s,22-diol and hopan-6α,7s,22-triol were isolated and identified as the main lichen constituents. This is the first report of the occurrence of 2-methoxy-3,6-dimethyl-4-hydroxybenzaldehyde in lichens.

Pannaria conoplea and P. tavaresii (Ascomycota: Pannariaceae ) new to Chile

A collection of lichens made in 1998 (by WQ) from the bark of Austrocedrus chilensis at a locality in southern Chile, disclosed two species of Pannaria not hitherto recorded from the Chilean lichen mycobiota (Galloway & Quilhot 1999): (1) the pantemperate taxon Pannaria conoplea (Ach.) Bory, which is widespread in the Northern Hemisphere as well as having rare outliers in East Africa, Venezuela, Ecuador and Australia (see Jorgensen 1978; Swinscow & Krog 1988; Jorgensen & Galloway 1992; Jorgensen & Arvidsson 2004), and (2) Pannaria tavaresii P. M. Jorg., known earlier from North America (including Mexico and Jamaica), Portugal, Macaronesia (Jorgensen 1978), Australia (Jorgensen & Galloway 1992), Sardinia and Italy (Nimis 1993) and previously collected in 1986 from near Valdivia in Chile. The discovery of Pannaria conoplea and P. tavaresii in Chile adds to the known Pannaria mycobiota of Chile (Galloway & Quilhot 1999), bringing the total number of species of this genus in Chile to 23. Eleven taxa formerly placed in Psoroma , are now correctly accommodated in Pannaria (see Jorgensen 2001 b ; Elvebakk & Galloway 2003; Jorgensen & Sipman 2004; Passo et al . 2004). Both Pannaria conoplea and P. tavaresii are within the currently accepted circumscription of Pannaria (Jorgensen 1994, 2004 a , 2004 b ). Descriptions of the Chilean material are given below.

SECONDARY PRODUCTS FROM Pannaria tavaresii (LICHENS)

Pannarin, chloroatranorin, leprolomin, ursolic acid and ergosterol peroxide were isolated from Pannaria tavaresii P.M. Jorg. The results confirm that the chlorinated depsidone pannarin is the most representative compound in this lichen genus