Exam 34: Transport in Plants

At one point it was thought that capillary action was responsible for the flow of water through tree xylem.It was later found that capillary action could not account for the flow of water because

What happens when plant tissue has very low turgor pressure?

The movement of water containing dissolved sugars and other compounds in phloem sap is known as

The evaporative loss of water from the leaf is called

Endodermal cells differ from other root cells in that endodermal cells

_______ are proteins that allow water to diffuse rapidly across cell membranes.

Scientists were able to rule out the possibility of a pumping mechanisms in plants based on the observation that when the _______ were removed, water still rose up the trunk.

Capillary action alone cannot account for the movement of water through the xylem because capillary action

Unlike movement of fluid in the xylem, movement of sap in the phloem can be

Sieve tube elements lose most of their contents (Golgi apparatus, nucleus, etc.) as they develop.Which of the following makes this possible?

A newly developed fluorescent stain only stains the plasmodesmata.It is therefore marketed to plant physiologists as a product that will be useful for tracking movement through part of the _______ transport route.

Sinks differ from sources in that sinks

Which of the following is true regarding energy requirements for loading and unloading?

_______ are tissues in plants that are capable of storing energy for plants to use as well as for humans to exploit.

Consider a plant cell immersed in distilled water.Explain why, even if there is a negative solute potential inside the cell, there may be no net movement of water.

Which cells communicate with and provide metabolic functions for sieve tube elements?

In an experiment investigating the flow of water through xylem, scientists removed the roots from a tree and then placed the base in a vat of poison.The poison moved up the tree, killing all living cells as it went.How would the results differ if scientists had also removed the leaves of the tree?

In what way might a given structure on a plant function both as a source and a sink?

What happens to the flow of water as a cell's pressure potential becomes more positive relative to the environment?

In guard cells, what is the function of taking on K⁺ and Cl^- ions?