Abstract

The physiological performance of clonal plants is largely linked with resource translocation among interconnected ramets. Whereas carbon (C) and nitrogen (N) transferences have been evidenced in several herbaceous clonal plants, empirical evidence in woody species is anecdotal. We evaluated physiological integration in two evergreen tree species, differing in the light requirements in a temperate rainforest of Southern Chile: Embothrium coccineum J.R. et. G. Forster (light-demanding) and Eucryphia cordifolia Cav. (shade-tolerant). We measured light availability for vegetative (root suckers) and sexual (seed-origin plants; hereafter, saplings) recruits of the two species. Then, we compared elemental and isotopic leaf traits between recruit types and species growing under similar light availability. A (CO2)-C-13 field pulse labeling was performed on a set of Embothrium root suckers to quantify C transfer from moderately shaded suckers (donors) to highly shaded suckers (receivers). For the two species, leaf N concentration, delta C-13, and delta N-15 were higher in suckers compared to saplings. In the labeling experiment, the delta C-13 and C-12 equivalent excess did not differ between donor and receiver, indicating a weak C transfer between donors and receivers. Although the results from the pulse labeling were not conclusive, they suggest, together with the differences in natural isotope abundance, the existence of physiological integration in root suckers of both species. Our findings indicate that the formation of root suckers is more important for regeneration and persistence than for resource acquisition at an intermediate ecological succession of a temperate rainforest.