Photosynthetic responses to phosphorus nutrition in Eucalyptus grandis seedlings.
1990
Kirschbaum M.U.F. | Tompkins D.
Eucalyptus grandis seedlings were grown in growth units in which plant roots were suspended in air while continuously being sprayed with nutrient solution (aeroponic system). P was added to nutrient solutions in exponentially encreasing amounts which determined plant growth rates. Assimilation rates were correlated with leaf P content. This relationship was apparent on either a unit leaf area or unit leaf weight basis. Assimilation rates and leaf N content per unit leaf weight were also correlated. In contrast, there was no correlation between leaf assimilation rate per unit leaf area and N content per unit leaf area, as N content per unit area was similar for all P treatments. The differences between correlations on a weight and area basis were due to differences in specific leaf area in different treatments, with plants with lower P status having less leaf area per unit leaf weight. The photosynthetic measurements showed that CO2 assimilation rate, together with relative leaf growth rate, was one of the processes most sensitive to P nutrition.
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