Phosphorus requirement for biomass accumulation is higher compared to photosynthetic biochemistry for three ornamental shrubs

Ornamental nursery producers grow a variety of plant taxa in soil-less substrates and rely on frequent water nutrient applications to maximize growth quality. This study was performed understand the morpho-physiological basis response phosphorus (P) additions identify optimum P concentration required for three common woody ornamental taxa: Hydrangea quercifolia ‘Queen Hearts’, Cornus obliqua ‘Powell Gardens’ Physocarpus opulifolius ‘Seward’. In greenhouse experiment, all plants were watered with complete solution that varied (0, 0.7, 1.3, 2.5, 3.7, 6.5 mg L−1). Optimum photosynthetic biochemistry dependent ranged between 2.5 3.7 L−1. For total dry biomass, approximately 4.0 L−1 taxa. Phosphorus below reduced leaf size resulted greater partitioning biomass root growth. Analysis responses photosynthesis intercellular carbon dioxide (A/Ci curves) indicated continuous increase parameters increasing concentration. Rate rubisco carboxylation (Vcmax), RuBP regeneration rate (J), triose phosphate use (TPU) limited P-deficient Light-harvesting efficiency (Fv’/Fm’) less sensitive addition than or The optimal concentrations identified this are lower recommendations amounts provided by typical commercial fertilizers. Thus, these taxa, application above 4 combination excess irrigation resulting leachate could have negative environmental consequences without improving crop physiology.