Modes Of Action Herbicides

Question 1

Growth Regulators

Answer 1

Mimic plant auxins (IAA)

-cells stop elongation, continue to grow rapidly

most effective on Broadleaf weeds

Question 2

Mitotic inhibitors

Answer 2

Disrupt mitosis

no cell division
swollen club- shaped roots

Question 3

Pigment Inhibition/ Destruction

Answer 3

Inhibition of carotenoid formation. Carotenoid Destruction Inhibition f PROTOX or PPO
-leads to high levels of PROTO
–Potent photosensitizer that generates free radicals
-without PROTOX
–proto generaes free radicales and damages membranes

Question 4

Lipid Inhibition

Answer 4

Inhibition of Acetyl-CoA carboxulase (ACCase)
-meristematic region of shoots and leaves
-long chains of fatty acids
-developing shoots and leaf surfaces

Question 5

Ammonia Detoxification

Answer 5

Ammonia is produced and is normally detoxified by incorporation into glutamine by the enzyme GLUTAMINE- SYNTHASE
-blockage of this enzyme causes a build up of toxic levels of ammonia and rapid plant death

Question 6

Cell Membrane Disruptors

Answer 6

Result from formation of highly toxic free radicals, singlet oxygen, peroxides
-cell membranes begin to leak, cell ruptures and dies, occurs very rapidly