AGR6422C_2_Chlorine-(Cl)_description Flashcards
How does chlorine occur in nature?
Occurs in aqueous solution (e.g., soil solution) as the monovalent ion chloride (Cl-).
Is chlorine mobile in the soil?
Yes.
Is chlorine mobile in the plant?
Yes.
How is chlorine taken up by the plant?
As free chloride (Cl-), against an electrochemical gradient since is a negative anion, by chloride transporters.
What are two essential functions chlorine serves in the plant?
- Enzyme activation
2. Osmotic regulation
What are three ways chloride is involved in osmotic (stomatal) regulation?
- Plant turgor regulation
- Stomatal regulation
- Osmoregulation
How is chlorine involved in photosynthetic oxygen evolution (PSII)?
Chlorine is involved in the splitting of water to oxygen and protons at the oxidizing site of PSII.
What role do chloride anions have in proton pumping V-type ATPase on endomembranes?
The Cl- anion seems to be involved in particular in stimulating (i.e., increasing activity) the proton pumping V-type ATPase on endomembranes.
For which crops is chlorine deficiency most likely?
In crops with higher chlorine demand.
What are some symptoms of chlorine deficiency?
- Youngest leaves first.
- Wilting of leaves, esp. leaf margins
- Shriveling and necrosis
- Roots stubby in appearance
- Non-uniform chlorotic or necrotic lesions
Wet deposition supplies most of the necessary chlorine in most cropping systems, except in which region?
The Great Plains, which are characterized by low Cl inputs in wet deposition with leached soils.
From where do most chlorine inputs to soils occur?
- Rainwater
- Fertilizer applications (e.g., KCl)
- Irrigation waters
- Sea spray
- Dust
- Air pollution
What are some typical amounts of chloride in plant tissues?
0.2-2%
What are typical sufficient chloride levels needed for growth?
0.02-0.04%
