Biological activities allelopathic

Plant physiologists and other biological scientists also have their important role to play in allelopathy. They must devise suitable bioassays to detect the suspected allelopathic compounds, follow the biological activity of the individual and associated chemicals, develop activity profiles for identified chemicals, and determine the conditions (dose/response) for chemicals to arrive at the threshold levels. They must also determine which chemicals contribute... 

Some effort has been directed toward understanding the growth requirements of the alga of interest, allelopathic alga (13), the optimum salinity (14), the distribution of allelopathic agents (15), and the temperature optimum (16). This paper reviews the approaches taken to separate the allelopathic agents from the other materials and the methods used to characterize the biological activity of aponin from Nannochloris sp. 

Once biological activity has been established (in the laboratory or the field) and once the chemical work has been accomplished, we need to confirm allelopathic activity in the natural environment. To accomplish this end, the effects of soil and microbial flora must be considered. Thus, the disciplines of soil chemistry and microbiology are required. The chapters in this volume deal primarily with the biology and chemistry of phytotoxins isolated from plants however, we hope that these topics will stimulate soil chemists and microbiologists to contribute to solving the problems associated with the study of allelopathy. Thus, the purpose of this volume is not only to bring before the scientific community a representation of research efforts in the area of allelopathy, but also to promote the relationships... 

Studies on Piqueria trinervia. A very interesting study is that of the allelopathic potential of Piqueria trinervia and its piquerols A and B, by Gonzalez de la Parra et al. (14). It was found that this widely distributed weed in the Valley of Mexico has a wide biological activity upon other plants. 

Of the several plants with reported allelopathic activity that we at PCRI have examined, none has yet yielded dramatic results. A bioassay-directed approach has yielded modest biological activity which seems to lessen or disappear in pursuing a purified product. This latter accentuates the difficulties of pursuing allelopathic chemicals, the activity of which are due to additive and or synergistic effects of the compounds involved. They must be meticulously studied. 

The allelopathic potential of plants has often been evaluated from tests of the biological activity of volatiles, leachates, and root exudates, or from aqueous extracts of the tissue. Alternatively, assessment of inhibitors in the soil associated with a suspected... 

The first phase or initial stage of screening include bio-assays. Those plant materials that are confirmed to possess biological activity through bio-assay need to be further studied for their dose response pattern under controlled environment. Plant materials elucidating appreciable response even at minimal doses could be further evaluated for their allelopathic potential under natural habitats. 

Chung, I.M., Ahn, J.K., Yun, S J. Identification of allelopathic compounds from rice (Oryza sative L.) straw and their biological activity. Can J Plant Sci 2001 81 815-819. 

Heisey, R. M. 1999. Development of an allelopathic compound fromtree-of-heaven (Ailanthus altissima) as a natural product herbicide. In Cutler, H. G and Cutler, S. J. (Eds.), Biologically Active Natural Products Agrochemicals, CRC Press, Boca Raton, FL, 57-68... 

Perhaps plans have not heen formulated in several cases, or results disseminated. The avenues of research that the identification of a natural product may open are many, so that in the true sense these compounds may be considered allelochemic (J )as opposed to strictly allelopathic. For example, the discovery of a novel biologically active natural product logically presupposes that the metabolic pathway will eventually he elucidated, that possible synthesis, or partial synthesis may be attempted, that homologs and analogs will be described and that other areas may be considered for eventual employment of these materials, not only in more obvious uses such as pesticides, hut also medicinal and non-biological areas. An example of a non-biological use is that of orlandin ( ) which is denatured in acetone to produce an acid and base resistant product which is ceramic-like and is not soluble in organic solvents. 

Biological Activity Plant Growth Regulator Activity Allelopathic Effects Plant Allomones... 

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