Allelopathy is the chemical inhibition of one plant species by another through the release of allelochemicals that affect the growth of neighboring plants. This can occur via various plant parts and soil, impacting germination and nutrient uptake. Examples of allelopathic plants include black walnut and sorghum, which produce specific chemicals that can inhibit the growth of other species.

1. What is Allelopathy?
The word allelopathy derives from two separate words.
They are allelon which means "of each other", and pathos which means "to
suffer".
Allelopathy refers to the chemical inhibition of one species by
another. The "inhibitory" chemical is released into the
environment where it affects the development and growth of
neighboring plants.
Allelopathic chemicals can be present in any part of the plant.
They can be found in leaves, flowers, roots, fruits, or stems. They can also
be found in the surrounding soil.

2. Allelopathy: Allelopathy is the production of chemical(s) or
exudates by living and decaying plant species which interfere with
the germination, growth or development of another plant species or
microorganism sharing the same habitat.
Examples of allelopathic plants:
1. Black walnut (Juglans nigra)
2. Sorghum
3. Lantana
4. Imperata cylindrica is allelopathic on tomato, cucumber, maize
rice, glnut, olera, cowpea, pepper.
5. Cyperus esculentus– is allelopathic a rice, maize
6. C. rotundus – is allelopathic on barley

3. Plant canopy: Major effect of plant canopy is to shade
the understorey plants and limit their ability to synthesize
carbohydrates.
A competitive crop should be able to establish complete
ground cover.
Some low grow crops which can provide early ground
cover and shade out weeds when intercropped with other
crops are melon and sweat potato

4.  Allelopathy refers to the beneficial or harmful effects of one
plant on another plant, both crop and weed species, from
the release of biochemicals, known as allelochemicals, from
plant parts by leaching, root exudation, volatilization, residue
decomposition, and other processes in both natural and
agricultural systems.

5. Target species are affected by these toxins in
different ways. The toxic chemicals may inhibit
shoot/root growth, they may inhibit nutrient
uptake.

6. Chemical Warfare in the Plant
Kingdom
Black Walnut-The chemical
responsible for the toxicity in Black
Walnut is Juglone and is a respiration
inhibitor.
Tree-of-Heaven-Ailanthone, an
allelotoxin extracted from the root bark
of Ailanthus.
Sorghum- Sorgolene is found in the
root and disrupts mitochondrial
functions and inhibits photosynthesis.

7. EXAMPLES OF ALLELOPATHIC CHEMICAL INCLUDES
 Caffeic acid
 Chlorogenic acid
 Ferulic acid
 Gallic acid
 Vanillic acid
 Vanillin

8. PRODUCTION OF ALLELOCHEMICAL
 Allelochemical produce by weeds affect crops. They
are produced by any plant organ, with roots, seeds,
leaves being the most common sources flower and
fruits may also produce allelopathic chemical but
these are of less value in term of allelopathic effect.
 Allelochemical enter the environment though
volatilization foliage leaching or root exudation. They
may also result from decomposition of plant residues,
numerous chemicals present in plant material, are
also released when plant residues are left on the soil
surface after harvest or they are released during
decomposition of the plant residues.


9. Have you noticed allelopathy or allelopathic-like
influences in your neighborhood?Elsewhere?
Why is studying allelopathy important?
What are some beneficial implications of
allelopathy? How can these be used for the
betterment of the planet?