Abstract

Aims Gevuina avellanaandLomatia dentataare Proteaceae species from evergreen temperate forests, but onlyG. avellanacan colonize nutrient deprived volcanic depositions. We hypothesized that under nutrient deprivation,G. avellanawould present higher survival, physiological performance, and adjustment regarding cluster root (CR) formation and carboxylate exudation rate thanL. dentata. Methods We evaluated relative growth rate, maximal photosynthetic rate, photochemical performance, nitrogen (N) and phosphorus (P) leaf concentrations, specific leaf area, photosynthetic P and N use efficiency (PPUE and PNUE), CR formation and carboxylate exudation rate. Plants were grown in a greenhouse, using recent volcanic substrate and watered with different nutrient Hoagland (H) solutions: modified full Hoagland, without P, without N, or tap water. Results Both species showed high survival.G. avellanaexhibited higher growth rates (RGR), and higher CR number and biomass allocation under nutrient deprivation, but lower carboxylate exudation rates thanL. dentata. Malate, oxalate and succinate were detected in root exudates ofG. avellanabut only oxalate inL. dentata. However, PPUE and PNUE were higher inL. dentatathan inG. avellana. Conclusions Our hypothesis was not entirely accepted, CR formation was more "constitutive" inG. avellana, and composition of carboxylates was more diverse, with lower exudation rates thanL. dentata. Moreover,L. dentatashowed higher PNUE and PPUE, partly explained by thinner leaves. Different responses are related with edaphic conditions, where both species inhabit: more diverse toG. avellanaand restricted to developed soils toL. dentata.