Phloem loading with sucrose and subsequent entry of water takes place (respectively)

Phloem loading with sucrose and subsequent entry of water takes place against the concentration gradient of sucrose and along the concentration gradient of water respectively.

Phloem Loading with Sucrose (Against Concentration Gradient): Sucrose is actively transported from the photosynthetic source cells (typically in the leaves) into the companion cells and sieve tube elements of the phloem. This active transport involves energy expenditure and occurs against the concentration gradient of sucrose, meaning that sucrose is moved from an area of lower concentration to an area of higher concentration.

Subsequent Entry of Water (Along Concentration Gradient): As sucrose is actively loaded into the phloem, it increases the solute concentration within the sieve tube elements. This increase in solute concentration creates an osmotic potential gradient. Water from adjacent cells, often the neighboring xylem or surrounding parenchyma cells, then enters the sieve tube elements passively, following the osmotic potential gradient created by the accumulation of sucrose. Water moves from an area of higher water potential (less solute concentration) to an area of lower water potential (higher solute concentration) along its concentration gradient.