Getting to the root of carbon reserve dynamics in woody plants: progress, challenges and goals
Simon M. Landhäusser, Henry D. Adams
Abstract
Non-structural carbon (NSC) compounds are the primary products of photosynthesis that in their basic forms of glucose and fructose provide the fuel for cell physiological functions. They are also the fundamental building blocks of structural and non-structural primary and secondary metabolites used in processes such as defense, signaling and osmoregulation to adjust for drought and frost conditions. Glucose, fructose and their derivatives are therefore critical components for the maintenance, growth and reproduction of plants, but also for the less-studied processes of their allocation to defense and reserves. While photosynthesis is the primary source of these building blocks, it is important to recognize that the allocation of NSC to the different structures and functions within a plant also includes feedback mechanisms that regulate photosynthesis directly or indirectly (Körner 2003, 2015). As such, NSC should be viewed as an integrator of a multitude of plant physiological processes, such that disentangling the impact of individual processes from each other on NSC remains a challenge. For example, the interpretation of changes in NSC concentrations on their own without the context of a plant’s condition before, during and after stress events is very difficult. Therefore, the need for a better understanding of NSC allocation patterns and mechanisms is crucial in anticipating and potentially predicting how plants, in particular the long-lived species, will respond to current and future abiotic and biotic stresses.