This study aimed to characterize the nutritional demands of the young plants of Brazilian ginseng (Pfaffia glomerata (Spreng.) Pedersen) in a Paleudalf soil by means of the missing nutrient technique. Plantlets of P. glomerata produced in vitro and acclimatized ex vitro were used as start matter for the glasshouse experiment. Ten days after plant transfer to soil, fertilizations (by means of nutritive solutions) were done corresponding to nine treatments: control (without fertilization), complete fertilization (with macro and micronutrients), and with the omissions of N, P, K, Ca, Mg, S and micronutrients (Zn, B, Cu, Fe, Mn and Mo). At 60 days of cultivation, several growth parameters were evaluated. The number of leaves per plant was the growth parameter most affected by omission of N, K, S and P in the fertilization. The effect of nutrient omission in the fertilization on biomass partitioning between plant organs were differentiated. Accumulated shoot biomass obeied the following decreasing order, in relation with the nutrient omission: Mg <FONT FACE=Symbol>@</FONT> micronutrients > Ca <FONT FACE=Symbol>@</FONT> complete fertilization > P > S > K > N <FONT FACE=Symbol>@</FONT> control. While the root biomass obeied the following decreasing order: Mg <FONT FACE=Symbol>@</FONT> complete fertilization <FONT FACE=Symbol>³</FONT> P <FONT FACE=Symbol>³</FONT> micronutrients <FONT FACE=Symbol>³</FONT> S <FONT FACE=Symbol>³</FONT> Ca > N > K <FONT FACE=Symbol>@</FONT> control. Young plants of P. glomerata grow in a Paleudalf soil showed greater reduction in growth by omission of N, K, S and P in the fertilization. The omission of Mg and micronutrients in the fertilization were not limiting to the growth of young plants.
Brazilian ginseng; mineral nutrition; nutrient subtraction; mineral fertilization; Amaranthaceae
