Allelopathy refers to the detrimental effects of higher plants of one species (the donor) on the germination, growth of the development of the plants of another species (the recipient).
BRIEF HISTORY OF ALLELOPATHY
- Theophrastus and Democritus in the 5th and 3rd century B.C. was recognized the impact of allelopathy on Agriculture.
- In 1832 Decandolle worked on the Allelopathy field.
- The word of Allelopathy was first time introduced in 1937 by Molisch .
The secondary metabolites produced by the plants, have the allelopathic effect on the growth and development of another plants.
Occurrence of the allele-chemical:
- Roots and Rhizomes of the plants contain low amount of
- In the stems of the plants.
- High amount of allelochemicals are found in the leaves.
- Flowers and pollens also have.
- Allelochemicals are also present in the seeds and fruits of the plants.
MODE OF ALLELOCHAMICAL RELEASE
Allelo-chemicals may volatilize and be absorbed directly by the plants through atmosphere or may be taken up through the soil solution when these chemicals are gone into the soil through the dew.
Leaching is the removal of the water soluble substances from the plant body through the rain, dew, mist and fog.
Root exudates are those substances which are released through the roots of the plant into the surrounding medium.
A variety of the allelopathic chemicals are released through roots of the plants which effect the growth of the microorganisms and higher plants.
Decomposition of the crop residues:
Large amount of the allelochemicals are released through the decomposition of the crop residues into the soil and also into the atmosphere.
FACTORS EFFECTING OF PRODUCTION OF ALLELO CHEMICALS
- Mineral deficiency
- Water stress
- Allelopathic agents
- Age of the plant
MODE OF ACTION OF ALLEO-CHEMICALS
- Cell division
- Cell elongation
- Phyto hormone induced growth
- Permeability of cell membrane
- Availability of P & K
- Mineral uptake
- Stomatal opening and photosynthesis
- Protein synthesis
- Clogging and corking of xylem
Israr Masood* and Imran Ramzan1
*Author Department of Soil and Environmental Sciences, 1 Co-author Department of Agronomy, University of Agriculture Faisalabad, Pakistan