Is Photosynthesis Nutrient Limited in Tropical Trees?

LOUIS S. SANTIAGO; GUILLERMO GOLDSTEIN

Tropical Tree Physiology. Adaptations and Responses in a Changing Environment

Springer

Año: 2016; p. 299 - 318

Abstract Tropical forests play an enormously important role in the global cyclingof carbon. However, the extent to which nutrients limit the potential for tropicaltrees to increase carbon gain as atmospheric carbon dioxide rises, a phenomenonknown as the carbon-concentration feedback, is uncertain. This chapter addressesour current state of knowledge on nutrient limitation of photosynthesis in tropicaltrees, summarizing and synthesizing the results of over 20 studies on photosyntheticresponses to nutrient manipulation experiments. Our results indicate that nutrientlimitation of photosynthesis is widespread, but that contrasting species andecosystems vary in their responses, with savannah trees showing the least responseat the leaf scale. Second, although photosynthesis is strongly limited by N inparticular species, N limitation of photosynthesis is modest compared to P limitation of photosynthesis when considering all of the available literature. Finally,alleviation of nutrient limitation through addition of combined nutrient treatmentsproduces the strongest photosynthetic responses, highlighting the potentiallycomplex stroichiometric interactions among elements. The authors discuss severalways forward for resolving questions regarding the potential and limits of tropicaltrees to influence key carbon cycling processes and thus improve our ability toforecast global responses and feedbacks to climate chang