EFFECT OF ARTIFICIALLY INDUCED STRESS CONDITIONS ON THE GROWTH OF THE MEDICINAL PLANT HYPOXIS-HEMEROCALLIDEA

H. hemerocallidea corms are a rich source of hypoxoside which is used medically. Certain aspects of cultivation of this plant have been investigated in this study. Herbicide treatments were undertaken as weeds pose a problem in cultivated lands. It was found that 2,4-D amine and glyphosate killed the H. hemerocallidea plants. Paraquat at low concentrations allowed good growth and yielded a good hypoxoside content. The control plants, however, grew the best and produced the most hypoxoside. H. hemerocallidea apparently prefers poor soils with little nutrients. High levels of nitrogen, phosphorus and potassium are needed initially to produce a good biomass. Once the plants have been established the fertilizer treatment can be discontinued. Best hypoxoside production was achieved when nitrogen levels were low. This finding is in line with the fact that these plants naturally grow well in poor soils. The plants survived and grew best in a clay/shale soil rather than on either a sandy or a grey prismic columnar soil. The hypoxoside content of plants grown on the clay/shale soil was the highest.