#Question id: 13206

Given below are some of the statements that regulate the sucrose loading mechanism;

A) The solute potential or, more likely, the turgor pressure of the sieve elements

B) Sucrose concentration in the apoplast

C) The available number of symporter protein molecules

Possible observation given on how to avoid regulation;

i) increase in sieve element turgor above a certain threshold would lead to a compensatory increase in loading

ii) High sucrose concentrations in the apoplast would increase phloem loading

iii) SUT1 transporter mRNA and protein have been lower after 15 hours of darkness than after a light treatment. These data suggest that the concentration of SUT1 transporter molecules could regulate loading

iv) Decrease in sieve element turgor below a certain threshold would lead to a compensatory increase in loading

v) The transporter mRNA and protein high in darkness than lower in the light treatment

Which of the following combinations represents correct observation?