Which form is primarily associated with copper uptake in plants?

The form primarily associated with copper uptake in plants is the cupric ion. This ion, represented chemically as Cu²⁺, is soluble in water, allowing it to be absorbed efficiently by plant roots from the soil solution. Plants require copper for various physiological functions, including photosynthesis, respiration, and as a component of several enzymes involved in metabolic processes.

Copper sulfate, while it can be applied to soil and may release cupric ions upon solvation, is not the form that plants directly uptake; it must first dissociate to release the cupric ion. Similarly, the chloride ion and magnesium ion do not have a direct role in copper uptake, as they pertain to other essential nutrients and functions within the plant. Thus, the cupric ion stands out as the specific form that facilitates copper uptake.