ABSTRACT
Inorganic carbon (IC) concentration in soils has important effects on root physiology and plant growth that are the cumulative results of a number of biological, chemical, and physical processes. IC in the soil exists not only as gaseous CO2 but also as a pHdependent combination of dissolved CO2 (i.e., H2CO3), , and , collectively referred to as dissolved inorganic C (DIC). The impact of soil IC concentra-tions on plant growth has been a topic of research since Birner and Lucanus (1866; cited in Enoch and Olesen, 1993) reported a response of oat plant growth to irri-gation water enriched with IC. The aim of this chapter is to detail the physiological interactions between plant roots and IC and how shoot physiology and plant growth responds to uptake of IC by roots. The source and chemistry of root zone DIC has been briefly con-sidered (Section III). The uptake of IC by roots of aquatic plants is more extensively reviewed by Farmer (1996).
