Selecting Eucalyptus spp. Clones to Enable Higher Phosphorus Uptake Efficiency

Eucalyptus clones have wide plasticity and worldwide dispersion, growing satisfactorily in different edaphoclimatic conditions. Furthermore, clones with higher phosphorus (P) uptake efficiency can grow in soils with lower P availability, due to their fast growth, biomass, and wood production. These traits can promote reduced use of phosphate fertilizers in nurseries and cultivation areas, thus lowering input costs and the likelihood of soil contamination. However, Eucalyptus spp. clones with higher P uptake efficiency are still relatively unknown. Thus, the aim of this study was to investigate whether morphological, physiological, and biochemical characteristics of Eucalyptus plants influence nutritional P efficiency and influence plant growth. Three concentrations of P were used, 10% P (very low level P), 30% P (low level P) and 100% (standard level P), of the standard concentration of P in Hoagland and Arnon solution and three Eucalyptus spp. clones ( Eucalyptus dunnii, Eucalyptus saligna , and Eucalyptus urograndis ). Morphological variables associated with shoot and root systems, photosynthetic variables, chlorophyll a fluorescence, photosynthetic pigments, antioxidant enzyme, and acid phosphatase activity were evaluated. Phosphorus concentration of 10% did not promote the production of plants with desirable morphological traits. The highest acid phosphatase values were found in the shoots of E. urograndis and E. saligna grown in the concentration of 10% P. Seedlings of E. urograndis were the most efficient in absorbing P. Furthermore, the concentration of 30% P was the one recommended for plant production to reach economic and ecological benefits.