Loading of sucrose into sieve tube cells is done by (i)_______ and the unloading of sucrose from the sieve tube cells is done by (ii)________.
Active transport and passive transport
Passive transport and active transport
Active transport
Passive transport
Loading of sucrose into sieve tube cells is by (i)_______ and the unloading of sucrose from the sieve tube cells is by (ii)________.
Sucrose enters a phloem sieve-tube cell because of: