AUTOALLELOPATHIC EFEECTS OF FOLIAGE EXTRACTS ON SEED GERMINATION AND SEEDLING GROWTH OF GUAVA (PSIDIUM GUAJAVA L.)

Abstract

The autoallelopathic effects of foliage on seed germination and seedling development of guava (Psidium guajava L.) was investigated. Compared with the distilled water control, most of the aqueous extracts of 10, 20, 30, 40, and 50 g dry leaves of guava in a liter of distilled water reduced the final germination percentage, the germination rate, as evaluated by the corrected germination rateindex (CGRI), and the radicle growth rate. The detrimental effects on these parameters increased with the increase of the extract concentration. Using mannitol solutions with the same pH and osmotic potentials as the extracts resulted in significantly higher germination percentage and rate and radiclegrowth rate than most of their corresponding extracts. Consequently, it could be concluded that guava leaves contain allelochemicals which could inhibit seed germination and seedling radical growth of that species