Question 1

There are three giant redwoods in California that a person can actually drive through. Imagine that you look up right when you are in the middle of driving through the tree and continue looking up until you exit out the other side. What order of structures would you see as you were driving through the tree starting at the middle?

Accepted Answer

The correct order of structures in a tree is pith (center), xylem (wood), vascular cambium (growth layer), phloem (inner bark), and cork (outer bark). This means that as you drive through the tree, you would see the pith first, followed by the xylem, vascular cambium, phloem, and then cork. Choice D is the only option that follows this correct order.

Question 2

A botanist is studying the growth rings of a redwood tree. She notices that three concentric rings are very thin compared to the surrounding growth rings. What can she deduce from the presence of these thin growth rings?

Accepted Answer

The presence of thin growth rings suggests that the tree may have experienced a drought or had limited access to nutrients during that time period, causing decreased growth.

Question 3

Auxin can freely diffuse _____ a cell but can only _____ via a PIN channel.

Accepted Answer

Auxin can passively diffuse into a cell due to its lipophilic properties, but to be transported out of the cell, it requires the aid of a specific protein known as a PIN (Polar Auxin Transport) protein. Therefore, auxin can freely diffuse into a cell but can only exit via a PIN channel.

Question 4

A researcher examines a piece of oak tree bark under a microscope. He notices many small holes or spaces within his bark sample. What are these areas?

Accepted Answer

The small holes or spaces within oak tree bark are called lenticels. Lenticels allow for gas exchange between the plant and its environment.

Question 5

MOST of the height growth of a plant is due to:

Accepted Answer

The majority of a plant's height growth occurs in the elongation zone, where cells increase in size but not necessarily in number. This is because the apical meristem is responsible for producing new cells, but those cells then elongate to add height to the plant. While changes in cell number do contribute to growth, it is not the primary factor in height increase. Thickening of cell walls occurs in the zone of maturation and does not contribute to height growth.

Question 6

Suppose you invented a way to genetically transform all of the cells expressing meristematic identity in a plant so that they would fluoresce green. Suppose too that this transformation was heritable by daughter cells, such that they would also fluoresce as long as they continued to express meristematic identity, but would lose the ability to fluoresce irreversibly upon differentiating to a nonmeristematic cell type. You then genetically transform all the cells of a tree, and soon after examine a cross section of a branch stem. A few years later, you examine a cross section of another branch stem. What should you expect to see in comparing the two stem cross sections?

Accepted Answer

The answer of Suppose you invented a way to genetically...

Question 7

As trees get larger and the number of leaves increases, transpiration rates rise and demand for water increases. How do mature plant stems meet this added demand for water?

Accepted Answer

As demand for water increases, the vascular cambium, a layer of actively dividing cells between the phloem and xylem, continues to produce new cells on its inner surface. These cells differentiate into additional xylem cells, allowing for increased water transport to meet the needs of the growing plant.

Question 8

Vascular cambium is capable of producing:

Accepted Answer

Vascular cambium is responsible for producing secondary xylem and secondary phloem. It is a lateral meristem that adds layers of cells to the stem or root, resulting in an increase in girth or diameter. The secondary xylem is responsible for the transport of water and minerals, while the secondary phloem is responsible for the transport of sugars and other organic compounds. Both tissues are important for the proper functioning of plants.

Question 9

Which of the following cell types can become the meristem cells of a vascular cambium?

Accepted Answer

Procambial cells and parenchymal cells can differentiate into the meristematic cells of the vascular cambium, which is responsible for secondary growth in plants.

Question 10

Growth rings may be used to determine the age of trees in seasonal climates.

Accepted Answer

Growth rings show annual growth and can be counted to determine the age of a tree. This method is commonly used in dendrochronology, the study of tree rings.

Question 11

An increase in a plant's diameter resulting from the addition of new xylem and phloem is called _____ growth.

Accepted Answer

Secondary growth is the increase in diameter of stems and roots resulting from the activity of the lateral meristem, which adds new xylem and phloem to the plant. Primary growth, on the other hand, is the elongation of the stem or root resulting from the activity of the apical meristem. Longitudinal growth refers to growth in length, and herbaceous refers to non-woody plant growth.

Question 12

In general, when a cell or tissue type has to serve multiple functions that each contribute to fitness, natural selection is constrained from optimizing that tissue of cell type for any one function. With this concept in mind, fill in the blanks in the sentence below with the appropriate term: poor, positive, negative. The terms may be used once, more than once, or not at all.
"In angiosperms you would expect a _____ correlation between the diameter of the water conducting conduits and the mechanical strength of the wood. In gymnoperms you would expect the correlation to be _____."

Accepted Answer

The answer of In general, when a cell or tissue...

Question 13

Which of the following is produced by the vascular cambium?

Accepted Answer

The answer of Which of the following is produced by...

Question 14

The wood of gymnosperms is composed of _____, and the wood of angiosperms (e.g., a cherry tree) can consist of _____.

Accepted Answer

The wood of gymnosperms is primarily composed of tracheids, which serve both for support and water conduction. Angiosperms, on the other hand, have a more complex wood structure that includes both fibers for support and vessel elements for efficient water transport, in addition to tracheids.

Question 15

Vascular cambium is one of two lateral meristems; the other is cork cambium. A plant grows in diameter primarily through divisions of the vascular cambium. If you pull a small piece of bark off a tree, and then look at the bark's inside surface, what tissue are you looking at (ignore any remaining cells of vascular cambium that may be left)?

Accepted Answer

The inside surface of the bark is primarily composed of phloem tissue, which is responsible for transporting nutrients throughout the plant.

Question 16

When a redwood tree trunk increases in diameter (not height), this is a result of:

Accepted Answer

The growth in the diameter of the redwood tree trunk is due to the activity of lateral meristems. The lateral meristems, including vascular cambium and cork cambium, increase the girth of the trunk by producing new tissue on the inside and outside of the trunk, respectively. The shoot apical meristems and axillary buds are responsible for the height growth and branching of the tree. Floral meristems are responsible for the production of flowers.

Question 17

Fibers in angiosperm wood can support large mechanical loads because:

Accepted Answer

The answer of Fibers in angiosperm wood can support large...

Question 18

Angiosperm trees can support large diameter branches that extend far from their main stems due to the mechanical strength of their wood, a strength conferred by:

Accepted Answer

Fibers provide mechanical strength to angiosperm trees. Tracheids and vessels are involved in water transportation and living cells are not directly involved in providing mechanical strength.

Question 19

Which of the following statements is TRUE regarding secondary growth in vascular plants?

Accepted Answer

Secondary growth in vascular plants involves both the vascular cambium and the cork cambium. The vascular cambium is responsible for increasing the thickness of the stem by adding layers of vascular tissue, while the cork cambium produces cork, which forms part of the bark. This process causes the plant to grow in diameter, not height, contributing to the thickening of the stems and roots.

Question 20

Looking out your window, you may notice that the bark of a nearby oak tree has a mosaic appearance, consisting of deep fissures and relatively flat areas. What accounts for this mosaic appearance?

Accepted Answer

The mosaic appearance of oak tree bark is due to the formation of new cork cambia in distinct, discontinuous patches (choice C) and the formation of new secondary phloem in distinct, discontinuous patches (choice A).

Quiz 31: Plant Growth and Development