EFFECTS OF SALINITY AND ALKALINITY ON PANSY AND IMPATIENS IN 3 DIFFERENT GROWING MEDIA

The quality of irrigation water used for greenhouse crop production ca n strongly influence plant growth. However, the effect on plant growth is probably a combination of water quality and the type of growing me dia used. To determine the effect of saline and alkaline irrigation wa ter on plant growth and nutrition, pansy and impatiens were grown in p eat, peat:pine bark, and pine bark media under standard greenhouse con ditions. Salinity treatments of 0, 100, and 400 mg L-1 NaCl:CaCl2 and alkalinity treatments of 0, 100, 200, 300, and 400 mg L-1 NaHCO3 were applied at every irrigation. Salinity levels at 100 mg L-1 and greater caused necrosis of leaf edges, upward curling of leaves, and reduced newer number for pansy. Treatment symptoms for impatiens were reduced growth, general chlorosis, and reduced flower number. These treatment symptoms increased in severity for plants grown in pine bark. Alkalini ty levels at 200 mg L-1 and greater caused decreased newer number, nec rosis of leaf edges, and downward cupping of leaves of pansy. Treatmen ts symptoms of impatiens were general chlorosis, water-soaked appearan ce of leaves and leaf abscission. Elemental concentrations of sodium ( Na+), chloride (Cl-), calcium (Ca++), magnesium (Mg++), and potassium (K+) varied in media solution and tissue with symptom and treatment.