大家好我先發表一個問題
想問phloem點樣將啲sucrose運來運去？
我上網睇咗少少野

Cells in a sugar source "load" a sieve-tube element by actively transporting solute molecules into it. This causes water to move into the sieve-tube element by osmosis, creating pressure that pushes the sap down the tube. In sugar sinks, cells actively transport solutes out of the sieve-tube elements, producing the exactly opposite effect.

唔係好明點解個sieve-tube element一低咗water potential吸完水
就會無啦啦有個hydrostatic pressure推啲cell sap向上向下郁
究竟所謂何事？thx