2.4. Mineral nutrient analysis
To determine if HLS enhanced nutrient uptake, the
nutrient depletion from solutions was measured at the
end of the two-month experimentation period. Plant samples
were ground in a Wiley mill to a particle size of 1
mm and then analyzed for their mineral content following
dry ashing. Macronutrient (P, K, Ca, S) content were
determined by HPLC (DionexDX100) except for nitrogen
which was determined using a Leco CHN elemental
analyzer. Microelements were analyzed by atomic absorption
spectrometry (Perkin Elmer). The mineral analysis
results are given in tissue concentrations (tissue content
as a percentage of dry weight) and quantities (the consumption
of nutrient elements in mg) of each element in
order to present both physiological and agronomical data.