Why do vines need calcium?

• A. For the structure of cells and photosynthesis.
• B. For signaling in roots.
• C. For fruit scent development.
• D. For iron uptake.

Answer: (A)

Calcium’s main role in vines is to support the structure of cells and the stability of membranes. It binds to pectin in the cell wall, cross-linking the middle lamella, which helps cells keep their shape as they grow and expands. When cell walls and membranes are strong, tissues develop properly and the cells function well, creating a stable environment for the processes inside the chloroplasts that drive photosynthesis. That fundamental structural support is why this option is the best fit for why vines need calcium.

Calcium does participate in signaling in plants, including in roots, but that isn’t the primary reason vines require it. It’s not directly involved in fruit scent development, and it isn’t a key driver of iron uptake.