Allelopathy of saffron – a biological control of Phalaris minor

Weeds can inhibit the growth and yield of many agronomic plants by release of phytotoxins to the plant environment. Phalaris arundinacea has less effect on seed germination but reduces growth, causes twisted roots, inhibits root development and kills the roots of test plants. Obviously, allelopathy can be used as biological weed control. Many species of medicinal plants have pronounced allelopathy effects as well. The present study evaluates the allelopathy effect of saffron (Crocus sativus L.) in a germination bioassay using Phalaris minor Retz (Poaceae). Leaf, corm and soil attached to corm (SAC) was assumed as the main sources of allelopathy. Water extracts of these sources at five concentrations (0, 0.5, 1, 3 and 5%) were used in 3×5 factorial arrangement with three replications. Plumule and radicle fresh weight of P. minor were reduced significantly by SAC treatment by -47% and -49.9%, respectively, compared to treatments with water extracts of leaf and corm. Both plumule and radicle lengths showed significant reduction by treatments with water extracts of leaf and corm. Water extracts at 3% and 5% concentration reduced germination by 27% and 55% compared to control [1]. Plumule and radicle fresh weights were reduced at 0.5% water extract by 51 and 50%, respectively, when compared to their controls. Plumule and radicle lengths were reduced significantly at 0.5% (-39%) and 1% (-44%) concentrations respectively compared to their control [1,2]. There was a significant source by concentration interaction for all germination traits. Leaf water extract at all concentrations had more negative effects on plumule and radicle lengths compared to water extracts of corm and SAC.

References: [1] Hosseini M, Rizvi S J H. (2003). Third National Symposium on Saffron. Iran. PP. 173–178. [2] Singh H P, el al.(2002). Critical Review in plant Science. 18: 757–772.