Both water and nutrients are limiting in arid environments, and desert plants have adapted to these limitations through numerous developmental and physiological mechanisms. In the Mono Basin, California, USA, co-dominant Sarcobatus vermiculatus and Chrysothamnus nauseosus ssp. consimilis are differentially N and P limited. We hypothesized that low leaf N resorption contributes to N-limitation in Sarcobatus and that low leaf P resorption contributes to P-limitation in Chrysothamnus. As predicted, Sarcobatus resorbed proportionally 1.7-fold less N than Chrysothamnus, but reduced leaf P in senescent leaves to lower levels than Chrysothamnus (8.0–10.8-fold lower based on leaf area or mass, respectively), consistent with N, but not P limitations in Sarcobatus. Again, as predicted, Chrysothamnus resorbed proportionally 2.0-fold less P than Sarcobatus yet reduced leaf N in senescent leaves to lower levels than Sarcobatus (1.8–1.3-fold lower based on leaf area or mass, respectively), consistent with P, but not N limitations in Chrysothamnus. Leaf N and P pools were approximately 50% of aboveground pools in both species during the growing season, suggesting leaf resorption can contribute significantly to whole plant nutrient retention. This was consistent with changes in leaf N vs. P concentration as plants grew from seedlings to adults. Our results support the conclusion that N-limitation in Sarcobatus and P-limitation in Chrysothamnus are in part caused by physiological (or other) constraints that prevent more efficient resorption of N or P, respectively. For these species, differential nutrient resorption may be a key physiological component contributing to their coexistence in this saline, low resource habitat.
Drenovsky, Rebecca E. and Richards, J. H., "Low leaf N and P resorption contributes to nutrient limitation in two desert shrubs" (2006). Biology. 26.