Allelopatiska egenskaper av tomatidin och andra alkaloider från potatisväxter

Sammanfattning: Alkaloids are a heterogeneous group of secondary metabolites in plants with toxic attributes. These substances often have toxic effects on different organisms and are found in many species of the nightshade family (Solanaceae). This study shows that the alkaloid tomatidine from tomato (Solanum lycopersicum) are allelopathic to arabidopsis (Arabidopsis thaliana, cv. Col), cornflower (Cyanus segetum) and tobacco (Nicotiana tabacum, cv. SRI) but not to tomato itself. The allelopathic effect were shown to be specific for tomatidine, the other 8 structurally similar alkaloids from nightshades that were tested did not yield the same effect. The plant material was grown in MS-medium containing tomatidine and its root growth were inhibited due to impaired cell elongation. The roots were deformed and shorter in the presence of 1 - 5 μM tomatidine compared to untreated control plants. The addition of sterols or plant hormones to arabidopsis grown in tomatidine did not stimulate the root growth. Germination of seeds from different agricultural plants were not affected by tomatidine, however, the growth was retarded which resulted in significantly less germinating seeds of flax (Linum usitatissimum).