Allelopathic potential of aqueous extracts of passion fruit Passiflora mucronata fruit peels on lettuce

Abstract

Pesticide misuse has led to problems in agriculture, contamination of environment, and human health. However, research into alternative methods of controlling invasive plants is expanding. The allelopathic effect of secondary metabolites from plant parts suggests a potential and sustainable alternative to plant residues for use as bioherbicides. Given the above, the current study aimed to investigate the allelopathic potential of various concentrations of the aqueous extract of fruit peels of genotypes of Passiflora mucronata in seed germination and seedling growth of Lactuca sativa L. Fruit peels of genotypes of P. mucronata were used to obtain an aqueous extract, which was then filtered and diluted at the following concentrations: T1=100; T2=50; T3=25; T4=12.5 mg mL-1; T5= negative control (distilled water) and T6= positive control (glyphosate). Germination was carried out in Petri plates and was conditioned in a biochemical oxygen demand germination chamber at 25 ± 2 °C. Macroscopic evaluation was performed at the germination stage and root and aboveground growth of the seedlings, and the germination velocity index were also evaluated. Cytogenetic analysis was performed, and mitotic index was obtained. The design was entirely randomized, with five repetitions of 25 seeds each. Allelopathic substances found in the bark of P. mucronata fruits interfere with seed germination and vigor, as well as initial seedling growth. The germination of L. sativa seeds was 100% inhibited by extract concentrations of 50 % and 100 %. The cell cycle of L. sativa seeds is inhibited by allelopathic substances present in the bark of P. mucronata fruits. It is concluded that aqueous extracts of Passiflora mucronata have an allelopathic inhibitory effect on germination and initial growth of L. sativa