In a ring-girdled plant:
Function of companion cells is:
1. | Loading of sucrose into sieve elements |
2. | Providing energy to sieve elements for active transport |
3. | Providing water to phloem |
4. | Loading of sucrose into sieve elements by passive transport |
The translocation of organic solutes in sieve tube members is supported by:
1. root pressure and transpiration pull
2. P-proteins
3. mass flow involving a carrier and ATP
4. cytoplasmic streaming