 allelopathy is a biological phenomenon by which an organism produces one or more biochemicals that influence the growth, survival, and reproduction of other organisms. these biochemicals are known as allelochemicals and can have beneficial (positive allelopathy) or detrimental (negative allelopathy) effects on the target organisms. allelochemicals are a subset of secondary metabolites, which are not required for metabolism (i.e. growth, development and reproduction) of the allelopathic organism. allelochemicals with negative allelopathic effects are an important part of plant defense against herbivory. allelopathy is characteristic of certain plants, algae, bacteria, coral, and fungi. allelopathic interactions are an important factor in determining species distribution and abundance within plant communities, and are also thought to be important in the success of many invasive plants. for specific examples, see spotted knapweed (centaurea maculosa), garlic mustard (alliaria petiolata), casuarina/allocasuarina spp, and nutsedge. the process by which a plant acquires more of the available resources (such as nutrients, water or light) from the environment without any chemical action on the surrounding plants is called resource competition. this process is not negative allelopathy, although both processes can act together to enhance the survival rate of the plant species. ==history== the term allelopathy from the greek-derived compounds allelo- and -pathy (meaning "mutual harm" or "suffering"), was first used in 1937 by the austrian professor hans molisch in the book der einfluss einer pflanze auf die andere - allelopathie (the effect of plants on each other) published in german. he used the term to describe biochemical interactions that inhibit the growth of neighbouring plants, by another plant.{{citation| title = allelopathy: a physiological process with ecological implications| year = 2006| publisher = springer| pages = 1| isbn = 1-4020-4279-5| last1 = roger | first1 = manuel joaquÃ­n reigosa| last2 = reigosa | first2 = manuel j.| last3 = pedrol | first3 = nuri
Botany Chemical_ecology