Questions and Answers of Botany An Introduction To Plant Biology

Plants never absorb so much water that their cells ______________, but they frequently lose enough water to ______________ because their protoplasts do not press firmly against the ________________
All of the protoplasm of one plant can be considered to be one continuous mass, called the _______________________________. Walls and intercellular spaces of a plant are called the
In glands, the apoplast consists mostly of __________________________. In nonglandular regions, the apoplast is mostly ________________________.
What is a motor cell? Name two plants that have them. Describe how motor cells adjust the position of a leaf.
In phloem transport, the sites from which water and nutrients are transported are known as __________ _______________________________ are sites that receive transported phloem sap.
During spring and summer, which organs are the dominant sources of sugar? When are tubers or fleshy taproots likely to be important sources?
As sugars are pumped into sieve elements, water follows. What happens? Do sieve elements merely become turgid?
Phloem sap is under pressure. What is the danger associated with this? How are P-protein and callose involved in counteracting this danger?
As sugar is actively transported into phloem in sources, what happens to the water potential of the cells losing the sugar? Does it become less negative?
Consider the pressure flow model of phloem transport. How do sugars and water enter the phloem from the source? How do sugars and water move from one phloem cell to another?
Can the direction of phloem transport change? Does phloem ever transport material into a leaf?
What is a leaf like early in the morning with respect to conditions that affect water movement? Describe what happens as the sun rises.
What is the speed of xylem sap translocation in ring porous trees?
Many roots remain healthy with their water potentials as low as _____________.
Imagine lifting an icicle. You must pull against its _________________ and the __________________ of the icicle in a tube (the cell walls), but lifting the top of the icicle raises the
Describe the cohesion-tension model of water movement through xylem. Would the weight of water be more of a problem in an upright tree or in a stolon? Why?
The breaking of a water column is called ________________. What breaks, the hydrogen bonds of the water or the cell walls of the tracheary elements?
When a water column cavitates, an air bubble is formed. The technical name is an _____________________.
In which habitat would you expect more cavitations—moist tropics or drier temperate areas? In which would you expect wood to have wide vessels, in which would you expect wood to have narrow vessels
If a vessel cavitates and fills with air, can it ever be refilled with water?
Most elements that are essential for plant growth are present in the____________ ____________ ____________ ____________. How do the elements become available?
What is meant by the microflora and microfauna of the soil? Why are they important?
How many bacteria typically occur in one gram of soil?
What is a hydroponic solution? After a solution of known composition which supports plant growth is found, how would you go about testing whether all of the chemicals in the solution are necessary
It is simple to grind up a plant and then extract and measure all of the chemical elements present, but this does not tell us which elements are essential. Why not?
List the major or macro essential elements. Why are they called that?
List the minor or micro (trace) essential elements. Why are they called that?
Are our modern reagents so pure that we can prepare a hydroponic solution that contains only the nine major and seven minor essential elements and nothing else? Can we be certain we have discovered
Do you think anyone has performed a mineral nutrition experiment that examined the entire life cycle of a giant redwood? A giant cactus? A mistletoe that is parasitizing an oak tree? What would be
To be essential, an element must be acting within the plant, not outside it. What does this mean? Discuss the roles of iron and phosphorus in determining which elements are essential for a plant.
We humans, like all other organisms, use a universal set of twenty amino acids in our proteins, but we cannot make ______________ of these ourselves. How many are plants unable to make? How many do
The differences in nutritional resources used by plants versus animals is also great. Plants obtain nutrients in the form of __________________ or as simple ______________ present in the environment.
Name the essential element involved in each process: changes the osmotic potential in guard cells as they swell or shrink, present in all nucleotides and amino acids, carries electrons in
Under natural conditions, is it rare or common to encounter plants whose growth is disrupted by a scarcity or an excess of mineral elements? Describe two habitats that often have excessive amounts of
Question 15 specified natural conditions. What about nonnative crop plants and ornamentals? Do they often encounter mineral deficiencies?Question 15Under natural conditions, is it rare or common to
Name and describe two common symptoms of deficiency diseases.
What is the difference between a mobile and an immobile element? Where are the first deficiency symptoms for each? Which elements are immobile?
Do we understand why certain minerals are immobile in plants? What is one essential element that we humans do not recycle well in our own bodies?
What are size ranges of particles of coarse sand, fine sand, silt, and clay particles (also called clay micelles)? Coarse sand can absorb a great deal of water during a rain, but what happens to the
Chemical weathering dissolves the surface of the crystal matrix of rock. As the matrix breaks down, what is released—positively charged cations or negatively charged anions? As a result, the
Many factors affect soil acidity, but probably the most important factor of all is _______________. Describe how this factor exerts its effect.
Most soils are ______________ to ______________ acidic. Desert soils, which have very little leaf litter or other organic matter, are usually _______________ (_____________________).
Describe cation exchange. How would decomposition of mulch and humus affect cation exchange? Why is acid rain so damaging?
The roots of most plants form a symbiotic association with soil fungi. Name the association and the element that it supplies to the plant.
Which essential element is neither a component of rock matrixes nor a contaminant in rock? Although this element is abundant in air, no plant or animal can absorb it from the air and use it. Why not?
The electrons that reduce nitrate to nitrite are brought to it by a short electron transport chain involving FADH2 and NADH (see Figure 13-16). In which other reactions have you seen these two
Name the three steps in the conversion of N2 into organic nitrogen that is part of a plant. Which type of organism is capable of performing each step?
What is nitrogenase? What chemical does it use as a substrate? It is extremely sensitive to ________________ and can function only if _______________ is completely excluded from it.
How does nitrogen reduction affect carbon fixation in the stroma reactions? How many molecules of NADPH must be diverted from one pathway to the other? How would respiration be affected?
Figure 13-18 shows several chemicals that carry nitrogen up from the roots to the rest of the plant. What is the unusual feature of these chemicals that make them good carriers?Figure 13-18
What is nitrogen assimilation? What is the acceptor molecule? What does it react with? What is the product?
What is transamination? If an amino group is passed onto oxaloacetate, which amino acid is produced? If an amino group is transaminated onto pyruvate, which amino acid is produced?
Growth by apical meristems has been previously described. In woody species, additional tissues are produced in the stem and root by two other meristems, the _______________________________________
Name at least three examples of woody plants that are trees and three that are shrubs.
Many herbs live for several years. How do they respond to the bottleneck of the limited conducting capacity of the first-year stem?
Which groups of plants have secondary growth? Which never do?
Figure 8-3 is complex but easy to understand. Figure 8-3B shows a tree trunk, and this year is its fourth year of growth. A transverse section at the base of Figure 8-3B would show how many layers
Imagine a tree that has a radius of 20 cm and that produces a new layer of wood 0.5 cm thick (the outer radius of the new wood is 20.5 cm and the inner radius is 20 cm). What is the cross-sectional
Woody plants are almost always perennial plants, often living for many years. Describe some advantages of this with regard to a plant’s ability to occupy a favorable site. Describe some
It must be difficult for secondary growth to arise by evolution. How many times has it evolved in the 420 million years that vascular plants have been in existence? How many of those have become
What is the name of the vascular cambium that arises within vascular bundles? Between vascular bundles? After the two have formed, what is the shape of the vascular cambium? Is it a series of strips
Imagine a tree that is growing in springtime. All woody parts that were present last year have a vascular cambium, but all of the twigs that are brand new have just primary growth with vascular
Look at Figure 8-6. Part (A) shows the lower half of a fusiform initial (actually most fusiform initials would be much taller than this), and part (B) shows the same cell after it has divided and one
What are the two types of cells in the vascular cambium? Can either type be converted into the other?
Look at Figure 8-8. Vascular cambium is not present; it was located far above the top of the micrograph, but you can see there are six rows of wood cells. How many fusiform initials were involved in
Are fusiform initials parenchyma cells, collenchyma cells, or sclerenchyma cells? Do they have chloroplasts, chromoplasts, or proplastids?
Are ray initials longer or shorter than fusiform initials? Can they undergo both periclinal and anticlinal divisions or just one or the other?
In gymnosperms (conifers like Christmas trees), what types of cells occur in the axial system (the cells produced by fusiform initials)? Which cells are very rare (Table 8-2)? Wood of conifers is
Ray initials are typically grouped together in short vertical rows only one cell wide (________________________), two cells wide (________________________) or many cells wide
True or false: Typically a vascular cambium never has large regions of only fusiform initials or ray initials.
What fraction of cells formed to the interior of the vascular cambium develop into secondary xylem, known as wood—less than half, exactly half, or more than half all cells?
Look at the woods of Figure 8-13. In part (B), all vessels have about the same diameter and are narrow, but the wood in part (C) has some very wide vessels (in the early wood) and some narrow ones
In basal angiosperms and eudicots, what types of cells occur in the axial system? What is the only type of cell present in the rays of eudicots? The wood of eudicots is called
What types of cells are derived from fusiform initials? What types of cells are derived from ray initials? Is it theoretically possible to have a vascular cambium without ray initials or without
What is a growth ring? How does early wood differ from late wood? Do all species of wood show strong differences between these two phases of a growth ring?
Why do some people prefer the term “growth ring” rather than “annual ring”? What can sometimes happen if a summer is unusually cool? Do you think this occurs more frequently in California or
If especially wide vessels are produced early in the growing season and only narrow, sparse vessels are produced later, the wood is said to be ________________________ porous; however, if vessels
The thickness of sapwood is some indication of how long a growth ring of wood is able to function. Look at Table 8-3. About how long does wood of catalpa function? How about wood of wild black cherry
What changes occur as sapwood is converted to heartwood?
What is a tylosis? How does formation of tyloses slow the spread of fungi in wood? Why doesn’t a tree make tyloses in vessels that are still conducting water?
Because secondary phloem is formed from the vascular cambium just as secondary xylem is, it too has an ________________________ system and a ________________________ system. Why do the size, shape,
In a cross-section of a tree, where are the oldest growth rings—in the outer region or nearer the pith? Where is the oldest secondary phloem— near the outside of the tree or near the cambium?
What causes the outermost tissues of a woody stem or root to become pushed outward and expanded?
The layer of cells that produces cork has a technical name and an ordinary name. Give each name.
Periderm consists of at least two types of cells. Sometimes a third is present. What are these three types of cell?
Are geraniums herbs or woody plants? Do they ever form bark (Figure 8-23)?Figure 8-23
Why does a layer of periderm offer only temporary protection? When the plant makes a new layer of cork cambium, does it make the new layer to the outer side of the failing periderm or to the inner
What type of plant produces the cork used for wine bottles and cork boards—pines, oaks, maples, eucalyptus, or none of these (Figure 8-25)?Figure 8-25 (A) (B) (C) (D) Outer bark Inner bark (E)
In which tissues does the first cork cambium form? When does it usually arise? In which tissues do later cork cambia form?
What is the function of lenticels? How are intercellular spaces important for this function?
Describe the formation of included phloem. How did the included phloem of Iresine in Figure 8-30A become surrounded by xylem?Figure 8-30A Included phloem Y (Of 8.1. (A) Produced by the
Do roots form wood and bark, or are these secondary tissues present only in stems?
Describe the anomalous secondary growth in roots of sweet potatoes. What is the selective advantage of this unusual type of secondary growth?
Describe the secondary growth of monocots like Joshua trees and dragon trees. What are secondary vascular bundles?
Describe the growth of a palm seedling. For the first few years of life, the seedling becomes wider, but without secondary growth, how is it able to do this? Each adventitious root adds something.
Why can a monocot like an iris branch and increase its number of leaves? Is the fact that the shoot is a rhizome with adventitious roots important? Is water transported from one end of the shoot to
What is the name of the analysis of tree rings? How is that used to study past climates? How is it used to establish the date when ancient buildings and ships were constructed?
In tree ring analysis, what is a floating sequence? Why has the sequence for the Middle East been floating, whereas we know the exact dates of each ring in the sequences for North America and Europe?
Reproduction can serve two very different functions. What are they?
Look at the apples in Figure 9-1a, all growing on a single tree. Do all of the seeds in all of the apples in the photograph have the same maternal parent? Do they all have the same paternal

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