Cell Membrane Disruptors

Front 1

What is the mechanism of action for arsenicals?

Back 1

- cell membrane disruptors
- POST with extensive translocation
- interferes with ATP production and certain enzyme activity, may also cause abnormal cell division, preventing new growth

Front 2

Why does arsenicals have no soil activity?

Back 2

- it is tightly bound to soil colloids
- arsenic is an element and does not breakdown in the soil

Front 3

What is the mechanism of action of diphenyl-ethers?

Back 3

- it inhibits chloroplast Protox causing the accumulation of protoporphyrinogen IX that leaks into the cytoplasm
- no enzymes in cytoplam to move reaction into making chlorophyll so it causes the enzymatic oxidation into protoporphyrin IX which reacts with O2 and light and produces oxygen radicals which reacts with lipids causing necrosis

Front 4

What other herbicides are Protox inhibitors?

Back 4

Flumiclorac
Oxadiazon
Sulfentrazone
Flumiozaxin

Front 5

What is the mechanism of bipyridylliums, i.e. paraquat?

Back 5

interrupts PSI diverting the normal flow of electrons to oxygen forming radical oxygen which subsequently forms phytotoxic free radicals, causing extensive cell membrane damage

Front 6

What processes may cause resistance to paraquat?

Back 6

- sequestration
- bound at cell wall
- limited uptake
- elevated antioxidants

Front 7

What is the mechanism of sulfcarbamide?

Back 7

- almost immediate damage
- rapidly broken down by plant enzymes into urea and sulfuric acid which occurs in or near cells dissolving it

Front 8

How is sodium chlorates used as a herbicide?

Back 8

- used as a preharvest desiccant
- used as a 'soil sterilant'
- strong oxidizing agent and may also be acting to block protein sulfation

Front 9

What is mechanism for copper?

Back 9

- interferes with water splitting rxn
- precipitates protein
- rate is important

Front 10

What is the herbicide that is a general biocide and toxic to fish?

Back 10

Acrolein