Aspects of the phosphorus nutrition of white clover populations. IIII cation exchange capacity

Abstract

Abstract Relationships between plant cation exchange capacity (CEC) and the ability of plants to tolerate low phosphorus (P) soils have been suggested. To investigate this the CEC of roots, leaves and stolons of 17 semi‐natural populations and three cultivars of white clover (Trifolium repens L.) were measured. Plants were grown in sand culture and solution culture with low phosphorus (P) supply (≍ 50 μM P) or high P supply (825–1291 μM P). The CEC of leaf was greater than that of stolon which in turn was greater than that of root material. Leaf CEC was closely correlated with stolon CEC (r=+0.80∗∗), and leaf CEC was correlated with root CEC (r=+0.69∗) but stolon CEC and root CEC were not significantly correlated (r=+0.48). Significant differences in CEC were found both between populations and between genotypes within populations. When plants were grown at high‐p root CEC and, to a lesser extent, stolon CEC, were correlated with plant growth rate. Leaf CEC tended not to be correlated with plant growth att...