The Impact of Drought Stress and/or Nitrogen Fertilization in Some Medicinal Plants

Abstract

SUMMARY Several pot experiments were set up to follow the impact of drought stress and/or nitrogen fertilization on the yield and secondary metabolites content of medicinal and aromatic plants (MAP) accessions held within Genebank for MAP in Slovenia. The results of pot trials with fenugreek and with deadly nightshade are presented. In fenugreek (Trigonella foenumgraecum L., Fabaceae) the maximal yield of dios-genin was achieved in plants grown under an optimal irrigation regime (35% depletion of available soil water). Drought stressed seeds of cv. Margaret contained less diosgenin (p = 0.0021) than irrigated plants (0.123%, dw). In deadly nightshade (Atropa belladonna L., Solanaceae), the content of tropane alkaloids was determined. The results of the plant treatment responses showed that the maximal yield of tropane alkaloids (hyoscyamine: 54 mg/plant; scopolamine: 7 mg/plant) was achieved in plants grown under an optimal irrigation regime (35% depletion of available soil water) accompanied with a total nitrogen supply of 0.37 g/pot. By contrast, the maximal content of alkaloids was achieved with 95% depletion of available soil water and a nitrogen supply of 1.60 g/pot.