The physiological assessment of the nutrient status of plants. I. Preliminary experiments with phosphorus

Abstract

Subterranean clover plants of different phosphorus status, obtained from pastures or raised in the glass-house, were transferred to nutrient solutions. These included a complete solution, and others each lacking a different element. Subsequent response patterns were defined by leaf area changes. Plants raised at low phosphorus levels showed considerably smaller increases in leaf area in the solutions without phosphorus than in the other solutions. These differences were discernible as early as 2 days after transfer. There was little difference between the control treatments and treatments omitting elements other than phosphorus. Plants raised at a more adequate phosphorus level did not show differences between treatments till much later. The results are discussed, and their use as a basis for a simple method of determining the nutrient status of plants is indicated.