Phytotoxic Impact of Mesquite (Prosopis juliflora) Pericarps on Seed Germination and Seedling Growth of Lettuce (Lactuca sativa)

Abstract

Phytotoxic effects of mesquite (Prosopis juliflora) pericarps on
seed germination and seedling growth of lettuce (Lactuca sativa) were
investigated. Aqueous extracts of 10, 20, 30, 40, 50 and 60 g of dry
mesquite pericarps in a litre of distilled water were used. Final seed
germination percentage and germination rate, evaluated with corrected
germination rate index, and days to 50% of the final seed germination,
were significantly reduced. Likewise were the radicle and the hypocotyl
lengths, five days after germination. The magnitude of the reduction
increased with the increase of extract concentration. Mannitol solutions
with the same osmotic potential and pH as the aqueous extracts resulted in
significantly higher values of these traits than their corresponding
extracts. This indicates that mesquite pericarp contains allelochemicals
which could detrimentally affect seed germination and seedling growth of
lettuce.