Phloem Transport Quiz

What is the direction of phloem translocation?

Either upward or downward

Which organs are considered sources?

Leaves and roots species

What characteristics makes an organ a sink?

Having phloem connection

In which case does a leaf act as a sink?

When it is young and requires an external source of energy

What factor(s) determine(s) source-to-sink movement?

The difference of water potential between source and sink

Where is phloem usually found in the vascular tissues?

In the outer side surrounding the xylem, except for some eudicots

Removing a ring of bark from a tree’s main trunk results in the plant’s death. Which organ will be initially affected, and by which the plant will ultimately die?

The root system

Which cell types to be part of the phloem tissue?

Sieve elements, companion cells, parenchyma cells

How is the cell architecture of sieve elects different from that of all other cell types?

Sieve elements lack nuclei, vacuoles, and in many cases Golgi bodies and ribosomes.

How are sieve element cells symplastically connected to other cells?

Through pores that can form sieve plates connecting to companion cells, and through plasmodesmata to other sieve element cells