The Population Age Structure of Spotted Knapweed (<i>Centaurea maculosa</i>) in Montana

Boggs, Keith W.; Story, Jim M.

doi:10.1017/s0043174500079042

Cited by 40 publications

(32 citation statements)

References 11 publications

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“…If the seeds are not dispersed far enough from the parent plants, the seedlings would be in a position to compete for resources, especially water. This selfregulatory effect of autotoxicity has been reported for Centaurea maculosa, where seeds that survive the auto-inhibitory pressure are likely to outlive and replace the parent plants eventually (Boggs and Story 1987;Perry et al 2005). Furthermore, the autotoxic compounds identified in our study may have allelopathic effects to suppress the growth of other species as well (Singh et al 1999).…”

Section: Discussionsupporting

confidence: 81%

Identification of autotoxic compounds from fibrous roots of Panax quinquefolium L.

Gao

Yang

et al. 2008

Plant Soil

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Panax quinquefolium (American ginseng) is a perennial understory herb that has been widely used as a medicinal plant in China and other countries. Autotoxicity has been reported to be one of the major problems hindering the consecutive cultivation of American ginseng. However, the potential autotoxic compounds produced by the root of American ginseng are less well known. Here, we report the isolation and characterization of five groups of autotoxic compounds from aqueous extracts of the fibrous roots of American ginseng. Ether extracts of the water-soluble compounds were further analyzed and separated into seven fractions. Among them, the most autotoxic fraction (Fraction V) was subjected to GC/MS analysis, and 44 compounds were identified. Based on literature information, 14 individual compounds were selected and their autotoxic effects on seedling growth were further tested. The results revealed that, of these 14 compounds, 9 phenolic compounds significantly reduced the growth of seedlings in a concentration-dependent manner, while 5 aliphatic compounds showed modest inhibition at all three concentrations tested. Furthermore, we verified the existence of the autotoxic compounds in the plow layer soil of commercially cultivated American ginseng fields, and the concentration of these compounds as determined by HPLC analysis was in line with the concentration determined to be bioactive. Taken together, our study established a functional link between the compounds produced by American ginseng and their autotoxic effects.

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Section: Discussionsupporting

confidence: 81%

Identification of autotoxic compounds from fibrous roots of Panax quinquefolium L.

Gao

Yang

et al. 2008

Plant Soil

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“…Dormant C. maculosa seeds can survive in the seed bank for at least 8 years (Davis et al . 1993), indicating that seeds prevented from germinating by high soil (±)‐catechin concentrations would be likely to outlive and, perhaps eventually, replace established C. maculosa adults (Boggs & Story 1987).…”

Section: Discussionmentioning

confidence: 99%

Retracted: Dual role for an allelochemical: (±)‐catechin from Centaurea maculosa root exudates regulates conspecific seedling establishment

et al. 2005

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Summary1 Plant allelopathic compounds may have other roles than interspecific interference. We investigated whether (±)-catechin, a phytotoxin exuded from the roots of the exotic invader Centaurea maculosa (spotted knapweed), is also one of the factors that regulates C. maculosa recruitment. 2 Adding activated carbon, which adsorbs organic compounds, to soil around C. maculosa adults in the field increased seedling density by 78% 25 days after sowing, and by 34% 32 days after sowing, suggesting that soil-borne compounds inhibited or delayed recruitment. 3 Analysis of field soils near mature C. maculosa revealed that they can contain exceptionally high (±)-catechin concentrations (mean = 1.55 mg g −1 dry soil, with 60% of samples containing ≥ 1.0 mg (±)-catechin g −1 ). 4 In laboratory experiments, treatment with ≥ 1.0 mg (±)-catechin mL −1 reduced seedling root elongation by > 50%, indicating that field concentrations are sufficient to inhibit C. maculosa recruitment. Provided that 10% methanol was used to maintain (±)-catechin in solution for > 1 day, treatment with ≥ 1.0 mg mL −1 also reduced C. maculosa germination by > 70%. 5 (±)-Catechin maintained in solution with methanol did not significantly reduce C. maculosa seed survival, suggesting that inhibition of germination was due, at least in part, to delayed germination rather than to seed mortality. 6 Depending on the solubility of (±)-catechin in soil and on the duration of its effects on recruitment, C. maculosa may avoid intraspecific competition or regulate the timing of seedling establishment by reducing seedling growth or postponing germination in response to its own phytotoxin. 7 Chemical regulation of C. maculosa recruitment, as demonstrated here, suggests a dual role of (±)-catechin as an allelochemical and an autoinhibitor. The potential for a single plant root exudate to influence both inter-and intraspecific interactions emphasizes the complex effects that plant secondary metabolites may have on plant population and community structure.

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“…(spotted knapweed), an invasive forb native to Eurasia, dominates more than 4 million ha of rangeland in the western United States, forming dense monocultures in areas once dominated by diverse grassland plant communities (Boggs and Story, 1987). A tap-rooted, short-lived perennial that over-winters as a rosette, C. maculosa begins growth early in spring and flowers late in summer while many neighboring native grasses and forbs are senescing (Sheley et al, 1999), and can take advantage of soil resources for a longer portion of the growing season.…”

Section: Introductionmentioning

confidence: 99%

Host plant differences in arbuscular mycorrhizae: Extra radical hyphae differences between an invasive forb and a native bunchgrass

Walling

Zabinski

2004

Plant Soil

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Arbuscular mycorrhizae affect grassland plant community composition and host plant nutrient uptake, and can mediate shifts in competitive outcome between plant species. Centaurea maculosa, an invasive forb from Eurasia, dominates more than 4 million hectares in the Rocky Mountain region of North America. We examined the role of AM for phosphorus (P) acquisition from a distant source for C. maculosa and Festuca idahoensis, a native bunchgrass. Plants were grown individually in pots divided by a barrier that either excluded plant roots and AM hyphae, or only plant roots. In the half of the pot without a plant, 1 of 3 P treatments was applied: no P, phosphate rock (PR) or triple superphosphate (TSP), applied at a rate of 144 mg P kg −1 soil. After 14 weeks of growth, C. maculosa was twice as large as F. idahoensis, and neither species' biomass was affected by barrier type. Phosphorus fertilizer, and especially PR, moved across the barrier to the plant side of the pot. Tissue P concentration for C. maculosa was highest with the PR treatment, and was not affected by the barrier type. In contrast, F. idahoensis tissue P concentration did not vary with barrier or P treatments. There was more AM extra radical hyphae (ERH) associated with C. maculosa than F. idahoensis, suggesting that C. maculosa provides more carbon for the AM fungi, resulting in greater ERH production, ERH soil exploration and potential for soil nutrient pool exploitation.Although not tested in this study, differences between host plants may be the result of different physiological characteristics of the host plant or differences in AM fungal species that colonize the invader, with different fungal species accessing P from different distances.

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The Population Age Structure of Spotted Knapweed (Centaurea maculosa) in Montana

Cited by 40 publications

References 11 publications

Identification of autotoxic compounds from fibrous roots of Panax quinquefolium L.

Identification of autotoxic compounds from fibrous roots of Panax quinquefolium L.

Retracted: Dual role for an allelochemical: (±)‐catechin from Centaurea maculosa root exudates regulates conspecific seedling establishment

Host plant differences in arbuscular mycorrhizae: Extra radical hyphae differences between an invasive forb and a native bunchgrass

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