Investigating the Allelopathic Effect of Aqueous Extract of Broomrape (Orobanche) on the Germination Mechanism of Garden Cress (Lepidium sativum)

Abstract

Weed plants primarily affect the growth and development of neighboring plants by releasing inhibitory substances into their surroundings. One of the main targets of these inhibitory effects is often seed germination. This study, conducted in 2023 in the laboratory of Samangan Higher Education Institution, aimed to examine the allelopathic effect of broomrape (Orobanche) on the germination and seedling growth of garden cress (Lepidium sativum). The experiment was designed as a completely randomized design (CRD) with three replications and four treatments, including concentrations of 100%, 66%, 33%, and 0% (distilled water as control) of the aqueous extract of broomrape. The results showed that increasing the concentration of the broomrape extract significantly decreased germination percentage, seedling length, and the inhibition index. The highest germination rate (96%) was observed in the control treatment (distilled water), while the lowest germination rate (30%) occurred in the 100% concentration treatment. Additionally, as the concentration increased from 33% to 100%, inhibition of garden cress seedlings ranged from 13% to 69%. Seedling length was also significantly affected. Overall, the findings demonstrated that broomrape has a strong allelopathic effect on the germination and growth of garden cress. Due to oxidative stress in the seed structure and a sharp reduction in germination, the use of broomrape extract as a bioherbicide for weed management and control is recommended.