ABSTRACT
Metabolic adjustment by plants in response to changes in their environment underpin a range of morphological and physiological adaptations. Allocation of compounds to phloem-mediated transport has a major influence over plant scale processes. In fully expanded leaves, over 90% of recently fixed carbon can be exported to the phloem stream. Despite this, the use of phloem contents as indicators of plant health has not received significant attention in part due to the difficulties in sample collection. Here we outline how metabolic shifts in the allocation of carbon among selected solute pools observed in phloem contents may be used as bio-indicators of plant health and vigor.
