|Webber Iii, Charles|
|Myers, Dwight - East Central University|
|Taylor, Merritt - Oklahoma State University|
|Shrefler, James - Oklahoma State University|
Submitted to: Journal of Agricultural Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/12/2014
Publication Date: 1/15/2015
Citation: Webber III, C.L., White Jr, P.M., Myers, D.L., Taylor, M.J., Shrefler, J.W. 2015. Impact of kenaf (Hibiscus cannabinus L.) leaf, bark, and core extracts on germination of five plant species. Journal of Agricultural Science. 7(2):93-98. DOI: 10.5539/jas.v7n2p93.
Interpretive Summary: Plants can interact and influence other plants through naturally produced chemicals from within a plant. This chemical interaction between plants, which is referred to as allelopathy, may result in one plant inhibiting the growth and development of the other plant. The objective of this research was to determine the portion of the kenaf plant that would have a greater detrimental impact on the germination and development for five other plants (redroot pigweed, green bean, tomato, cucumber, and Italian ryegrass). It was discovered that the leaf extract from the kenaf decreased germination of redroot pigweed, tomato, cucumber, and Italian ryegrass, but not the green bean seeds. The extracts from the kenaf core did reduce the green bean germination by 7.0%. Increasing the concentration of the kenaf extracts also typically reduced redroot pigweed, tomato, and cucumber germination. Green bean germination was unaffected by the kenaf extract concentration. Except for green beans, the extract from the kenaf leaves produced the greatest detrimental impact on the other plant seeds. Future research should investigate how to utilize these naturally occurring plant extracts to organically control weeds in horticultural, agricultural, and ornamental settings.
Technical Abstract: The chemical interaction between plants, which is referred to as allelopathy, may result in the inhibition of plant growth and development. The objective of this research was to determine the impact of kenaf (Hibiscus cannabinus L.) plant extracts on the germination and post-germination development of five plant species. Four concentrations (0, 16.7, 33.3, and 66.7 g/L) of kenaf leaf, bark, and core extracts were applied to the germination medium of redroot pigweed (Amaranthus retroflexus L.), green bean (Phaseolus vulgaris L.), tomato (Lycopersicon esculentum Mill.), cucumber (Cucumis sativus L.), and Italian ryegrass (Lolium multiflorum Lam.) seeds. The treated seeds were placed in a non-illuminated incubator at 27 deg C. Germination was recorded after 7 days in the incubator. Kenaf leaf extracts decreased germination of redroot pigweed, tomato, cucumber, and Italian ryegrass. Core extracts reduced green bean germination by 7.0% compared to bark and leaf extracts. Increasing extract concentrations decreased germination of redroot pigweed by 39.5%, tomato by 34.4%, and cucumber by 12.6%. Green bean germination was unaffected by extract concentration. Although the allelopathic activity varied according to the extract's source (leaf, bark, and core) and extract concentration, all the seeds evaluated, except for green beans, had the greatest decrease in germination due to the leaf extracts. The research demonstrated that kenaf leaf extracts were allelopathic in reducing seed germination for 4 plant species (tomato, cucumber, Italian ryegrass and redroot pigweed). Future research should pursue cultural practices to utilize these natural allelopathic materials to benefit crop production and limit weed competition, assess the impact of kenaf extracts on post-germination growth, and isolate the active ingredients in the kenaf extracts.