Allelopathy effects of Weeds.pptx Allelopathy effects on crop

Allelopathy effects on crop

1. Department of Agronomy BZU Multan

2. and weeds management

3. Background

rte
Application
6: N
Harmful
effects of
Herbicides

ground-water

4. ALLELOPATHY

Definition

Greek words

allelon which means "of each other"
pathos which means "to suffer".

“Allelopathy refers chemicals
released into the environment “aly”

where it affects the development „ y
and growth of neighboring plants” #4 »

5. Forms of Allelopathic Interactions

Forms of Allelopathy

ea I

Weed Weed

6. Allelopathic Interaction

1) Weed on Crop

Jungli pallak affect the wheat plant growth and development

7. Allelopathic Interaction
2) Weed on Weed

Impereta cylindrica (Cogon grass) inhibits the emergence and growth
of an annual broadleaf weed i.e. Borreria hispada (Button weed) by
exudation inhibitory substances through rhizomes.

8. Allelopathic Interaction

3) Crop on Weed

Oat, pea, wheat suppress the growth of Chenopodium album
(Lamsquarter)

9. Allelopathic effects of crops on weeds

Crop Weed sp. Source of inhibitors

Chenopodium album,

Amaranthus retroflexus
Abutylontheophrasti, Shoots and foliages

Amaranthus hybridus
Digitaria sanguinalis, Shoots and foliages

Ambrosia artimisifolia

10. Allelopathic Chemicals

Phenolic acid
>Coumarins

> Terpinoids
>Flavinoids

>Scopulatens

11. de me Pe

f Action of Allelochemicals

— a
earance bition of seedling Inhibition of root growth an:
Finslisre a growth, yellowish, and reduction of root activity
partial death

Chlorophyll and photosynthesis: Electronic conductivity
decreased increased

and respiration increased
Accumulation
of MDA

Structure af
ehigroplast and [AA
mitocondrion
be destroyed Membrane be destroyed
Lipid in membrane be peroxided
Decrease of SOD and POD activity

Released Alleloche:

Biochemical and

Physiological
Processes

icals: secalonic acid F (SAF)

Donor: Asperaiflus janonicus

12. Extract preparation of Allelochemicals

&- CD => Chopping

13. Types of allelopathy

1. True Allelopathy

The true allelopathy is the release of substances that are toxic in the form
in which they are produced in the plant.

2. Functional Allelopathy

Functional allelopathy is the release of substances that are toxic or a
result of transformation by micro-organism .

14. Ways of releasing Allelochemicals

Allelopathic chemicals are released from
the plants as:

Wolatitization

Pp

> Vapour — from root and leaf (through

stomata)
>Foliar ri A trom eaves
>Root

>Breakdown/ decomposition product of a es
dead plant parts

»Seed extract

Decomposition
of sigughed reo
y Menue

Exudation
thom roots

16. Advantages of Allelopathy

1) Limit competition for space,
light, nutrients, water

2) Autotoxity (Chemical produced
inhibits germination of it's own
seeds)

3) Allelopathic Weed Suppression h
Through the Use of Cover Crops fa

17. Allelopathy and Weed Management

Allelopathic extracts have been successfully
used for organic weed management.

Allelochemicals are diverse in nature and
structure and thus lack common mode of
action.

This phytotoxic activity of Allelochemicals is
responsible for growth suppression of weeds.

18. Allelopathy and competition

Plants will compete for sunlight, water
and nutrients.

“Allelopathic plants prevent other plants
from using the available resources and
thus influence the evolution and
distribution of other species.

19. Management of Plant Allelopathy

Arrangement of Cropping Systems

Crop allelopathy can be effectively used to f
control weeds in the field.

By intercropping those field crops which can }
suppress weeds of next crops

20. Management of Plant Allelopathy

Straw Mulching

Allelopathic applications, such as straw
mulching, provide sustainable weed
management

The allelochemicals from decomposed
straw can suppress weed growth in
farmlands, and reduce the incidence of
pests and diseases.