Increasing doses of germanium in the soil alter the primary metabolism of radish plants

Germanium (Ge) is a chemical element used in several industrial processes. According tothe Survey of Rocks and Soils of the Geological Service of Brazil (SGB-CPRM) thiselement is found in a wide territorial range in the country. Thus, The objective of this studywas to evaluate the primary metabolism of Raphanus sativus when grown with differentdoses of germanium, in relation to photosynthetic performance and growth for three cropcycles. The experiment consisted of growing radish in 7 treatments containing germaniumin the soil at concentrations of 0; 0.5; 1; 1.5; 2; 2.5; 3 mg kg -1 . Analyses were performedover three complete cycles of the crop, from seedling production, transplanting andharvesting. The parameters analyzed in each cycle were: growth, chlorophyllconcentration, chlorophyll a fluorescence, and stomatal conductance. The treatments withconcentrations up to 1.5 mg kg -1 , in all cycles, presented a better performance. Indicating apossible toxicity for levels above this.