Continuous remobilization from belowground provides more than half of all carbon and nitrogen in regrowing shoots after grassland defoliation

Remobilization of carbon (C) and nitrogen (N) from roots and crowns to regrowing shoots is an important strategy for grassland plants to tolerate herbivory. While this remobilization is thought to terminate once plants have the capacity to photosynthesize again and to take up N from the soil, this has rarely been quantified.
Here we investigated the remobilization of C and N to regrowing shoots of a perennial grassland under two defoliation frequencies (every 15 and 30 days) and two N fertilization levels (0 and 2.8 g m-2) by growing intact plant-soil cores for 60 days in a growth chamber. We measured the C remobilization from roots and crowns to regrowing shoots using a novel continuous 13C labelling method, and quantified the N remobilization to regrowing shoots and plant N uptake from soil with a 15N tracer method.
Regrowing shoots relied strongly on belowground C reserves, where up to 52% of C in regrowing shoots came from belowground during the first 30 days after defoliation. Belo..., The dataset was obtained from a growth chamber experiment after transferring intact plant-soil cores from a grassland near Camden, NSW, Australia.,