CHARACTERIZATION OF NUTRIENT DISORDERS OF GAZANIA RIGENS 'DAYBREAK WHITE'

Gazania rigens ‘Daybreak White’ plants were grown in silica sand culture to induce and photograph symptoms of nutritional disorders. Plants were grown with a complete modified Hoagland’s all nitrate solution: (macronutrients in mM) 15 NO3-N, 1.0 PO4-P, 6.0 K, 5.0 Ca, 2.0 Mg, and 2.0 SO4-S, plus µM concentrations of micronutrients, 72 Fe, 18 Mn, 3 Cu, 3 Zn, 45 B, and 0.1 Mo. The treatments causing nutrient deficient symptoms were induced with a complete nutrient formula minus one of the nutrients. Boron toxicity was also induced by increasing the element 10× higher than the complete nutrient formula. Reagent grade chemicals and deionized water of 18-mega ohms purity were used to formulate treatment solutions. The plants were automatically irrigated. The solution drained from the bottom of the pot and was captured for reuse. A complete replacement of nutrient solutions was done weekly. Plants were monitored daily to document and photograph sequential series of symptoms as they developed. Typical symptomology of nutrient disorders and critical tissue concentrations are presented. Out of the thirteen treatments, eleven exhibited symptoms. Deficiency symptoms of N, S, and Ca were first to manifest. Should nutritional disorders arise growers should first consider these three problems when trying to determine the possible cause.