The Allelopathic Potential of Kudzu (Pueraria montana)

Abstract

We explored the allelopathic potential of kudzu as a function of its phenolics. Aqueous and methanol extracts of different kudzu organs (leaf, stem, root, and seed) were assayed for allelopathy with the use of lettuce and radish seeds. Both leaf and root extracts significantly inhibited all of the measured germination indices (total germination, speed of germination, and coefficient of the rate of germination) (all P < 0.01). When treated with leaf extract, the total germination of both species was ∼ 20% less than the control. Furthermore, the leaf extract significantly reduced the speed of germination to 38 and 53% that of the lettuce and radish controls, respectively. Lettuce and radish seeds soaked in leaf and root extracts for 24 h imbibed less water (∼ 30% for both species) than those soaked in distilled water (control), suggesting that a reduction of water imbibition might be one of the mechanisms of germination retardation. Stem and seed extracts affected neither the water uptake nor the germination indices of radish and lettuce seeds. Kudzu leaves and roots contain higher amounts of total phenolics (P = 0.001) and soluble phenolics (P = 0.005) than stems and seeds, consistent with the results of the germination bioassays. In agar plate bioassays, both litter and rhizosphere soil had phytotoxic effects on the radicle growth of radish (P = 0.003) and perennial ryegrass (P = 0.001) seedlings. Perennial ryegrass and cobbler's pegs seedlings grown on leaf and root leachate-amended soil gave ∼ 40% shorter roots and shoots and ∼ 50% less dry weight than those grown in leachate-free soil. Kudzu litter was incorporated and incubated in soil for 6 wk, at which point the soluble phenolics in the soil solution were at a level (> 150 ppm) considered to be allelopathic.

Phytotoxicity induced by Phragmites australis: an assessment of phenotypic and physiological parameters involved in germination process and growth of receptor plant

“…germination showed that they are the most sensitive index compared to other germination indices for assessing the phytototoxic effect and such type of findings are well documented in other studies (Chiapusio et al 1997;Rashid et al 2010a). In addition, radicle length and biomass were inhibited more than hypocotyl length and biomass parameters, a common finding in phytotoxicity studies (Burgos & Talbert 2000).…”

“…Some studies report that the extracts of alfalfa, kudzu, and black mustard had inhibitory effects on seed imbibition (Chon et al 2004;Rashid et al 2010a;Tawaha & Turk 2003). Seed imbibition, the first phase of germination, is an important step to germination and if water uptake does not reach a Note: ***, **, * and ns indicate significant difference from control at P 5 0.001, P 5 0.01, P 5 0.05 and non-significant respectively after applying the Dunnett's test.…”

Allelopathic effects of Rhynchosia capitata on germination and seedling growth of mungbean

“…The results are supported by the findings of Rashid et al (2010), who reported impaired growth of lettuce (Lactuca sativa) and radish (Raphanus sativus) seeds (root and shoot length and fresh weight) by the allelopathic potential of leaf and root leachates of kudzu (Pueraria lobata). Tanveer et al (2008) also reported that minimum GI and germination percentage of rice seeds were observed when such seeds were treated with leaf leachates of Common Cocklebur (Xanthium strumarium).…”

“…Although many studies on the allelopathic potential of other legume weeds have been published (Kamo et al, 2003;Rashid et al, 2010), the allelopathy of R. capitata has not yet been evaluated. Rashid et al (2010) concluded that leaf and root leachates of kudzu (Pueraria lobata) have strong allelopathic potential which could impair growth of lettuce (Lactuca sativa) and radish (Raphanus sativus) seeds (root, shoot length and fresh weight).…”

“…Rashid et al (2010) concluded that leaf and root leachates of kudzu (Pueraria lobata) have strong allelopathic potential which could impair growth of lettuce (Lactuca sativa) and radish (Raphanus sativus) seeds (root, shoot length and fresh weight). Kohli et al (2006) reported that Acacia species affect crop growth by competing for various environmental resources as their litter interferes with the establishment and growth of the adjoining crop plants; in addition, numerous chemical substances, including phenolic compounds, are released in their litter (Seigler, 2003).…”