Summary1 Shade-tolerant angiosperm trees are reported to require relatively fertile soils in temperate forests. We explored the possibility that high foliage allocation in shadetolerant species could result in higher whole-plant nitrogen demands than in lightdemanding trees of comparable diameters. We measured foliage mass and area, leaf life span, and nitrogen (N) content of fresh foliage and leaf litter for juveniles of 11 evergreen angiosperms in a Chilean temperate rain forest. This permitted estimation of annual nitrogen losses in leaf litter fall by individuals of a given diameter. 2 Leaf life spans were longest in shade-tolerant species. The highest leaf N levels were found in small short-lived early successional trees, whereas among longerlived species there was no general relationship of leaf N with shade tolerance level. Shade-tolerant species had lower N resorption eciencies, and therefore higher leaf litter N concentrations on an area basis, than light-demanding associates. 3 Foliage mass, foliage area and total crown N pool were strongly positively related to shade tolerance level. 4 Interspeci®c variation in annual N losses in leaf litter fall was more closely related to foliage area (R 2 = 0.52) than to N concentration of leaf litter (R 2 = 0.31) or leaf lifetimes (R 2 = 0.01). Although the short-lived early successional species Embothrium coccineum had the highest annual crown N losses of the 11 species, shade-tolerant species had higher annual losses than light-demanding overstorey dominants of comparable longevities. 5 The results are consistent with the proposal that the costs of obtaining enough N for crown maintenance and expansion may constrain the ®tness of shade-tolerant angiosperm trees in late successional stages on infertile sites, when soil nutrient availability is reduced by increased uptake and sequestration in biomass and litter. On the other hand, high N loss rates may be more sustainable for short-lived early colonists that complete their life cycles in the initial stages of secondary succession, when nutrient availabilities are often relatively high.

Seedlings of nine southern Chilean trees were grown at three nutrient supply rates, to examine the roles of growth rate, biomass distribution and nutrient use traits in determining species natural distributions on resource gradients. Relative growth rate (RGR) showed no overall relationship with species site requirements, although RGR of fertile-site species tended to be more responsive to nutrient supply. In the low-nutrient treatment, infertility-tolerant Fitzroya cupressoides showed a higher RGR rank than a fertility-demanding species (Laurelia philippiana) which outgrew it substantially at the highest supply rate. This reversal of RGR ranks was associated with divergent nutrient use responses: at high nutrient supply both spp. had similar plant nitrogen concentrations (PNC), whereas at the low supply rate Fitzroya's production of biomass per unit of assimilated N was twice that of Laurelia's. However, this pattern does not appear to serve as a general explanation of the respective distributions of the study species, as RGR ranks of most species were unaltered by nutrient supply. At low nutrient availability, no clear differences in shoot:root ratio (SRR) were apparent between poor-site and fertile-site species. However, at high nutrient availability, SRR was markedly higher in the latter, resulting from differences in biomass allocation to stems (not leaves). Leaf area ratios (LAR) were higher in fertile-site species than in those tolerant of low fertility, because of differences in specific leaf area rather than leaf weight ratio. Very high LAR at high nutrient supply was characteristic of most shade-tolerant angiosperms, but not of shade-tolerant conifers. Although PNC showed no overall differences between poor- and fertile-site species, sensitivity of PNC to external supply rate was greatest in two infertility-tolerant conifers. In contrast, the angiosperm Weinmannia trichosperma, although tolerant of low fertility, responded to increased nutrient supply with greatly increased RGR and little change in PNC. Results show little trait convergence between conifers and angiosperms in adaptation both to shade and to infertile soils; i.e. fitness of different taxa in a given environment may hinge on different trait combinations.

RESUMENLas especies de Rhodophiala son plantas bulbosas nativas con potencial uso ornamental como plantas en maceta o de jardín. Son originarias de Chile, Bolivia, Argentina y Uruguay. En Chile, se distribuyen entre la II y X región (Schiappacasse et al., 2002). Algunas se encuentran creciendo y desarrollando exitosamente bajo climas extremos y en suelos cuyas propiedades físico-químicas, hídricas y nutricionales son muy limitadas. Su grado de adaptación a diferentes condiciones ambientales es asombroso; pues, muchas veces viven en poblaciones extensas y relativamente densas por ejemplo en el desierto de Atacama, uno de los más secos de la Tierra (Hoffmann, 1989). Por estas razones estas especies han desarrollado asociaciones simbióticas con hongos, formando micorrizas que las ayudaría a completar su ciclo de vida bajo períodos de estrés y a sobrevivir en ambientes áridos como por ejemplo el de la III región (Dhillion et al., 1995). Es de interés comprobar la presencia de Rhodophiala spp. micorrizadas, en otras zonas del país menos restrictivas desde el punto de vista medio ambiental. Para ello se escogieron las especies R. splendens, R. bagnoldii y R. phycelloides, determinándose diferentes lugares para la recolección del material vegetal (bulbos con raíces) y suelo. En laboratorio, a través de la tinción de raíces se determinó la presencia de micorrizas vesículo-arbúsculares, superando el 70 % de muestras micorrizadas en todas las especies. Posteriormente, para determinar el origen de la micorrización se sembraron semillas de R. splendens y R. phycelloides pregerminadas con y sin desinfección en suelos provenientes del hábitat natural no esterilizados y esterilizados en autoclave.Sólo se encontraron raíces micorrizadas en plántulas cultivadas en suelo sin esterilizar. Adicionalmente, mediante evaluaciones de materia seca, días a emergencia, diámetro de bulbos y longitud de raíces y hojas, se determinó que la