ABSTRACT
This chapter explores the optimal partitioning of assimilated N and C between resource acquisition structures and storage structures of an herbaceous perennial like alfalfa. One main reason for investigating allocation patterns in plants is to interpret and explain the relationships between the relative growth rate of a plant, its shoot/root ratio, and the shoot, and the rootspecific activities, which in turn depends upon the environment. Source-sink dynamics can be investigated in terms of carbon allocation schedules that ensure balanced exponential growth under a variety of environmental conditions during the initial vegetative growth phase or in terms of a life history perspective, where the pattern of carbon allocation is correlated to major phenological events. Photosynthate allocation to the symbiotic sink systems associated with the roots of alfalfa has important consequences with respect to the overall plant carbon economy. The symbiosis between plants and VA mycorrhiza is mutualistic and necessary for the survival of the fungi.
