in Spathiphyllum `Sensation' grown hydroponically. Leaf
nutrient contents of treated plants were analyzed to confirm suspected deficiencies. Leaf number,
leaf area and chlorophyll content were all significantly reduced in the nitrogen-deficient plants
similar to plants grown in distilled water. The phosphorus-deficient plants grew slowly but no
deficiency symptoms were visible on leaves. Many small yellow specks, usually 2 mm or less in
diameter, developed on the ad axial surface of lower leaves in the potassium-deficient plants. Leaf
area, but not leaf number, was significantly suppressed by the calcium-deficient treatment and the
young leaves developed necrotic margins on the middle and basal leaf blade. Fully expanded leaves
in the magnesium-deficient plants were distorted and had lower chlorophyll contents than the
controls. The iron-deficient plants showed interveinal chlorosis on younger leaves. The boron deficient plants showed two types of deficiency symptoms: a marginal necrosis at the leaf apex and
distorted and crinkled petioles break at the leaf blade. Shoot-root dry weight ratio was decreased
under N, P and Fe deficiencies but was increased under deficiencies of Ca and B. A key was
developed for the identification of mineral nutrient deficiencies