Allelopathic effects of Paspalum notatum Flüggé aqueous extract on seed germination and seedlings morphology of Tagetes patula L. and Zinnia elegans Jacq.

ABSTRACT: The reuse of agricultural waste such as plant biomass enables the sustainable production of ornamental plants; however, these materials can contain allelochemical compounds that can affect the growth. This study aimed to investigate the allelopathic effects of aqueous extracts from Bahiagrass (Paspalum notatum) biomass on seed germination and seedling morphology of two ornamental species, Zinnia (Zinnia elegans) and French marigold (Tagetes patula). Five concentrations of aqueous extracts from Bahiagrass leaves were used to soak the seeds of each species that were conducted separately. The variables analyzed included germination counts, germination speed index, percentage of normal and abnormal seedlings, percentage of non-germinated seeds (dead and dormant), hypocotyl, root and total seedling length, and fresh seedling weight. The results showed that Bahiagrass aqueous extract do not affected the seed germination of Zinnia and French marigold, even at higher concentrations. However, the Bahiagrass extract caused deformities in Zinnia and French marigold seedlings, with higher concentrations leading to an increased percentage of abnormal seedlings in both species. These abnormalities included hypocotyl curvature, shortened or absent roots, and root oxidation.