Showing papers on "Polygonum published in 1990"

Relationships between flooding tolerance, life history, and short‐term competitive performance in three species of polygonum

Abstract: The objective of this study was to compare the growth and short-term (single season) competitive performance of three species of Polygonum known to differ in flooding tolerance and life history. Polygonum amphibium is a perennial with low sexual reproductive effort and a relatively high degree of flooding tolerance, P. lapathifolium is an annual species with a high sexual reproductive effort and a low tolerance to flooding, and P. hydropiperoides is intermediate to the other two in terms of sexual reproductive effort and flooding tolerance

Mechanism of antimutagenicity of aquatic plant extracts against benzo[a]pyrene in the Salmonella assay

Abstract: The mechanism of antimutagenicity of water extracts of grass-wrack pondweed (Potamogeton oxyphylus Miquel), curled pondweed (Potamogeton crispus L.) and smartweed (Polygonum hydropiper L.) towards benzo[a]pyrene mutagenicity in Salmonella typhimurium was investigated. The antimutagenic components in the aquatic plants were water-soluble, heat-resistant and had a high molecular weight; chlorophyll did not play an important role.

Essential Oil of Polygonum minus Huds.

Abstract: Polygonum minus (kesom) was steam distilled to produce an oil in 0.3% yield. The chemical composition of the oil was examined in detail using a combination of GC/MS. Results obtained from the chemical analysis in combination with some preliminary plant propagation studies indicate that it is possible to obtain kesom oil which possesses a total aldehyde content > 87%. This can be achieved only when the plants are grown under controlled conditions. In total 28 compounds were identified in the oil.

Efficacy of five different formulations of clopyralid on Cirsium arvense (L.) Scop, and Polygonum convolvulus L

Abstract: Summary: Experiments were conducted in a controlled environment growth room to compare the phytotoxicity of five formulations of clopyralid and to determine the effect of post-treatment simulated rainfall applications on the efficacy of these formulations. Clopyralid, formulated as the acid, monoethanolamine salt, potassium salt, 2-ethylhexyl ester or 1-decyl ester was applied to Cirsium arvense or Polygonum convolvulus at the 8–10 and 4–6 leaf stage of development, respectively. Based on the shoot and root dry weight data from both species, the 2-ethylhexyl ester was consistently less phytotoxic than the other four formulations. With respect to Cirsium arvense shoot and root dry weight, there was no difference in efficacy between the acid, monoethanolamine salt, potassium salt and 1-decyl ester. Root dry weight changes of Polygonum convolvulus did not correlate well with an increase in dose of the five formulations. Maximum increase in stem diameter of Polygonum convolvulus occurred after application of 100 g a.e. ha−1 of the acid, monoethanolamine salt, potassium salt and 1-decyl ester whereas with the 2-ethylhexyl ester, the maximum increase occurred after application of 200 g a.e. ha−1. Simulated rainfall was applied 3, 6, 9 or 12 h after application of 200 g a.e. ha−1 of the five clopyralid formulations to both species. Rainfall reduced the efficacy of clopyralid, regardless of the formulation or species. The 2-ethylhexyl ester was less efficacious than the other four formulations, irrespective of the timing of simulated rainfall.

Composition for biocontrol of wild buckwheat

Abstract: The present invention is concerned with a novel bioherbicide and its use alone or in compositions, to control the growth of Polygonum convolvulus in agricultural crops such as cereals and other cultivated crops. The present invention is also concerned with a synergistic composition of the novel bioherbicide and a chemical herbicide. Specifically, the new fungus is Phoma sp. ATCC 20982.

Influence of perennial plants on chemical properties of arid calcareous soils in Iran

Abstract: The authors conducted a study in Bajgah to determine the influence of perennial plants on some selected properties of soils formed on the highly calcareous parent material. The major plant genera were determined to be Agropyron, Artemisia, Astragalus, Dianthus, Eryngium, Peganum, Polygonum, Stipa, and Thymus. Tops of plants genera were found to be significantly different in ash, N, P, K, Ca, Mg, Na, Mn, Zn, and Cu; the concentration of Fe was not significantly different. The authors found the plants to differ significantly in their influence on soil properties. Peganum caused an accumulation of organic matter (OM) as high as 7% in the soil, in an environment where the soils typically contain less than 1% OM. Soil concentrations of P, K, Mn, Zn, and Cu were also found to vary significantly beneath different plant genera. They suggest these differences in OM accumulation were caused by plant litter. Concentration of Fe in the soils formed beneath different plant genera was statistically unchanged.