Quantifying and understanding reproductive allocation schedules in plants: a lifetime of decisions

Abstract

O_LIA plant's reproductive allocation (RA) schedule describes the fraction of surplus energy allocated to reproduction as it increases in size. RA schedules distinguish between energy allocated to different tissue types and thus links to a key physiological trade-off in an organism's functioning and life history. While theorists have adopted RA schedules as an elegant connection between life history and energy allocation, little is known about RA schedules in real vegetation.\nC_LIO_LIHere we review what is known about RA schedules for woody plants using studies either directly quantifying RA, or which collected data from which the shape of an RA schedule can be inferred.\nC_LIO_LIWe find that RA schedules vary considerably across species: some species abruptly shift all resources from growth to reproduction (the \"big-bang\" strategy); most others gradually shift resources into reproduction, but under a variety of graded schedules (\"partial bang\", \"asymptotic\", \"gradual\", and \"declining\"). Available data suggest the maximum fraction of energy allocated to production ranges from 0.1 to 1 and that shorter-lived species have higher initial RA and increase their RA more quickly than do longer-lived species.\nC_LIO_LI Synthesis Available data suggests a wide variety of RA schedules exist among plant species. The collection of more data on RA, and not only on easy-to-measure proxies such as maximum height, would enable a tighter integration between theory and observation in plant ecology.\nC_LI