Question

Differences between positive hydrostatic pressure gradient and negative hydrostatic pressure.

Answer 1

Positive hydrostatic pressure gradient	Negative hydrostatic pressure gradient
When the difference in pressure exerted by a fluid at a given point due to gravity is towards gravity.	When the difference in pressure exerted by a fluid at a given point due to gravity is against gravity.
In plant cells, the turgor pressure is the positive hydrostatic pressure.	In plant cells, the pressure developed in xylem and in the walls between cells is negative hydrostatic pressure.