Plant Physiology, 3rd ed

675 Pages·2006·17.85 MB·English

Plant Physiology, 3rd ed
by Lincoln Taiz and Eduardo Zeiger
Hardcover: 690 pages
Publisher: Sinauer Associates; 3 edition (Aug 30 2002)
Language: English
ISBN: 0878938230
Book Description
With this Third Edition, the authors and contributors set a new
standard for textbooks in the field by tailoring the study of plant
physiology to virtually every student—providing the basics for
introductory courses without sacrificing the more challenging
material sought by upper-division and graduate-level students.
Key pedagogical changes to the text will result in a shorter book.
Material typically considered prerequisite for plant physiology
courses, as well as advanced material from the Second Edition,
will be removed and posted at an affiliated Web site, while many
new or revised figures and photographs (now in full color), study
questions, and a glossary of key terms will be added. Despite the
streamlining of the text, the new edition incorporates all the
important new developments in plant physiology, especially in cell,
molecular, and developmental biology.
The Third Edition's interactive Web component is keyed to
textbook chapters and referenced from the book. It includes
WebTopics (elaborating on selected topics discussed in the text),
WebEssays (discussions of cutting-edge research topics, written by
those who did the work), additional study questions (by chapter),
additional references, and suggestions for further reading.
Book Info
Plant Physiology textbook covers the transport and translocation of
water and solutes, biochemistry and metabolism, and growth and
development. Twenty-three scientists contributed to the text.
doi:10.1093/aob/mcg079
Plant physiology. 3rdedn. research literature is greatly facilitated in this way. A
L. Taiz and E. Zeiger. glossarygivingabriefexplanationofmanytechnicalterms
reinforces thisimpression.
Sunderland: Sinauer
An outstanding feature of this textbook is the large
Associates. $104·95.690pp.
number of crisp figures, most of them in full colour.
Although also rendering the figures aesthetically pleasing,
Plant physiology ispartof the
the use of colour usually serves a didactic purpose (which
essential core curriculum
maywellbeitsprimarycause).Ifoundnoneofthefiguresto
every botanist has to master.
be overladen with detail nor of inappropriate (microscop-
As usually non-motile organ-
ically small orinflated) size.Fullmarksfor this!
isms that are, in most cases,
PlantPhysiologyisamoderntextbookwith arefreshing
fixed to a single locality for
style and layout. The overall impression is one of a well-
their entire lifetime, plants
thought-outteachingaid.Theauthors/editorshaveachieved
have special needs to cope
aremarkablefeatinbringingitup-to-datewithoutallowing
with widely disparate, and
often highly changeable environmental conditions. any dead wood to accumulate (a symptom of ageing that
Physiological adaptations play as great a role in the unfortunately befalls the majority of textbooks as they
evolutionary struggle for life of a plant as morphological advance through numerous editions). Let’s hope they will
ones. be able to retain this phoenix-like rejuvenating potential in
Plant physiology by Taiz and Zeiger (and a plethora of future editions. In its third edition, Plant physiology
contributing expert authors) is a well-received, established successfully defends its position in the top league of
textbook aimed at students taking introductory courses in botanical textbooks. It is excellently produced, attractive
the field. One’s first impression of the book is one of and fun to use. It can even make an aged botanist wish he
excellentcraftsmanship:fromtheeye-catchingcover,tothe were an undergraduate student again!
quality of the paper and print, this third edition of Plant
physiology is not only comprehensive, it is attractive. A Thomas Lazar
singleencounterwillturnthefirst-timeuserintoapotential
buyer.Thebookissubdividedinto25chapters,groupedinto
Annals of Botany 91: 750-751, 2003
three larger sections (water, metabolism and development)
© 2003 Annals of Botany Company
thatcoverthemajortopicsofmodernplantphysiology.All
topics are treated in a very balanced way, with approxi-
mately equal weight being lent to each. Starting with the
basics of each subject, the reader is taken to the very
forefrontofcurrentknowledge.Thewritingstyleissuccinct
and lucid throughout, and the text is arranged in a two-
column format that is very reader-friendly. Specific topics
are easy to find using the detailed table of contents or
index.
Inthelightoftheexplosivegrowthofourunderstanding
of physiological processes in plants resulting from techno-
logical advances in the field of molecular biology, it is an
amazingachievementtofindthattheauthorshavemanaged
to keep the book’s length to a ‘mere’ 690 pages. That this
has not been achieved at the expense of including recent
literature is borne out throughout the book: figures 19–41,
for example, have been adopted from a 2001 publication.
Theextensivereferenceliststhatconcludeeachchapteralso
demonstratehowup-to-datethisthirdeditionis,withalarge
proportionofthereferencesdatingfromthelast5years.The
transferoftheapprenticefromthetextbooktotheforefront
http://3e.plantphys.net/
Chapter
1
Plant Cells
THE TERM CELLIS DERIVED from the Latin cella, meaning storeroom
or chamber. It was first used in biology in 1665 by the English botanist
Robert Hooke to describe the individual units of the honeycomb-like
structure he observed in cork under a compound microscope. The
“cells” Hooke observed were actually the empty lumens of dead cells
surrounded by cell walls, but the term is an apt one because cells are the
basic building blocks that define plant structure.
This book will emphasize the physiological and biochemical func-
tions of plants, but it is important to recognize that these functions
depend on structures, whether the process is gas exchange in the leaf,
water conduction in the xylem, photosynthesis in the chloroplast, or ion
transport across the plasma membrane. At every level, structure and
function represent different frames of reference of a biological unity.
This chapter provides an overview of the basic anatomy of plants,
from the organ level down to the ultrastructure of cellular organelles. In
subsequent chapters we will treat these structures in greater detail from
the perspective of their physiological functions in the plant life cycle.
PLANT LIFE:UNIFYING PRINCIPLES
The spectacular diversity of plant size and form is familiar to everyone.
Plants range in size from less than 1 cm tall to greater than 100 m. Plant
morphology, or shape, is also surprisingly diverse. At first glance, the
tiny plant duckweed (Lemna) seems to have little in common with a
giant saguaro cactus or a redwood tree. Yet regardless of their specific
adaptations, all plants carry out fundamentally similar processes and are
based on the same architectural plan. We can summarize the major
design elements of plants as follows:
• As Earth’s primary producers, green plants are the ultimate solar
collectors. They harvest the energy of sunlight by converting light
energy to chemical energy, which they store in bonds formed when
they synthesize carbohydrates from carbon dioxide and water.
2 Chapter 1
• Other than certain reproductive cells, plants are non- FIGURE 1.1 Schematic representation of the body of a typi- (cid:2)
cal dicot. Cross sections of (A) the leaf, (B) the stem, and (C)
motile. As a substitute for motility, they have evolved
the root are also shown. Inserts show longitudinal sections
the ability to grow toward essential resources, such
of a shoot tip and a root tip from flax (Linum usitatissi-
as light, water, and mineral nutrients, throughout
mum), showing the apical meristems. (Photos © J. Robert
their life span. Waaland/Biological Photo Service.)
• Terrestrial plants are structurally reinforced to sup-
port their mass as they grow toward sunlight against
the pull of gravity.
unlike animal development, depends solely on patterns of
• Terrestrial plants lose water continuously by evapo-
cell division and cell enlargement.
ration and have evolved mechanisms for avoiding
Plant cells have two types of walls: primary and sec-
desiccation.
ondary (Figure 1.2). Primary cell wallsare typically thin
• Terrestrial plants have mechanisms for moving water (less than 1 µm) and are characteristic of young, growing
and minerals from the soil to the sites of photosyn- cells. Secondary cell wallsare thicker and stronger than
thesis and growth, as well as mechanisms for moving primary walls and are deposited when most cell enlarge-
the products of photosynthesis to nonphotosynthetic
ment has ended. Secondary cell walls owe their strength
organs and tissues.
and toughness to lignin, a brittle, gluelike material (see
Chapter 13).
OVERVIEW OF PLANT STRUCTURE The evolution of lignified secondary cell walls provided
plants with the structural reinforcement necessary to grow
Despite their apparent diversity, all seed plants (seeWeb vertically above the soil and to colonize the land.
Topic 1.1) have the same basic body plan (Figure 1.1).The Bryophytes, which lack lignified cell walls, are unable to
vegetative body is composed of three organs: leaf, stem, grow more than a few centimeters above the ground.
and root. The primary function of a leaf is photosynthesis,
New Cells Are Produced by Dividing Tissues
that of the stem is support, and that of the root is anchorage
Called Meristems
and absorption of water and minerals. Leaves are attached
to the stem at nodes, and the region of the stem between Plant growth is concentrated in localized regions of cell
two nodes is termed the internode. The stem together with division called meristems. Nearly all nuclear divisions
its leaves is commonly referred to as the shoot. (mitosis) and cell divisions (cytokinesis) occur in these
There are two categories of seed plants: gymnosperms meristematic regions. In a young plant, the most active
(from the Greek for “naked seed”) and angiosperms (based meristems are called apical meristems; they are located at
on the Greek for “vessel seed,” or seeds contained in a ves- the tips of the stem and the root (see Figure 1.1). At the
sel). Gymnospermsare the less advanced type; about 700 nodes, axillary buds contain the apical meristems for
species are known. The largest group of gymnosperms is the branch shoots. Lateral roots arise from the pericycle, an
conifers (“cone-bearers”), which include such commercially internal meristematic tissue (see Figure 1.1C). Proximal to
important forest trees as pine, fir, spruce, and redwood. (i.e., next to) and overlapping the meristematic regions are
Angiosperms, the more advanced type of seed plant, zones of cell elongation in which cells increase dramatically
first became abundant during the Cretaceous period, about in length and width. Cells usually differentiate into spe-
100 million years ago. Today, they dominate the landscape, cialized types after they elongate.
easily outcompeting the gymnosperms. About 250,000 The phase of plant development that gives rise to new
species are known, but many more remain to be character- organs and to the basic plant form is called primary
ized. The major innovation of the angiosperms is the growth. Primary growth results from the activity of apical
flower; hence they are referred to as flowering plants(see meristems, in which cell division is followed by progres-
Web Topic 1.2). sive cell enlargement, typically elongation. After elonga-
tion in a given region is complete, secondary growthmay
Plant Cells Are Surrounded by Rigid Cell Walls
occur. Secondary growth involves two lateral meristems:
Afundamental difference between plants and animals is the vascular cambium (plural cambia) and the cork cam-
that each plant cell is surrounded by a rigid cell wall. In bium. The vascular cambium gives rise to secondary xylem
animals, embryonic cells can migrate from one location to (wood) and secondary phloem. The cork cambium pro-
another, resulting in the development of tissues and organs duces the periderm, consisting mainly of cork cells.
containing cells that originated in different parts of the
Three Major Tissue Systems
organism.
Make Up the Plant Body
In plants, such cell migrations are prevented because
each walled cell and its neighbor are cemented together by Three major tissue systems are found in all plant organs:
a middle lamella.As a consequence, plant development, dermal tissue, ground tissue, and vascular tissue. These tis-
(A) Leaf
Upper epidermis
Leaf primordia (dermal tissue)
Cuticle
Shoot apex and Palisade
apical meristem parenchyma
(ground tissue)
Bundle sheath
Axillary bud
parenchyma
with meristem
Xylem Vascular
tissues
Mesophyll Phloem
Leaf Lower epidermis
(dermal tissue)
Node
Guard cell
Internode
Stomata
Spongy mesophyll
(ground tissue)
Lower epidermis
Cuticle
Vascular (B) Stem
tissue
Soil line Epidermis
(dermal tissue)
Cortex
Ground
Pith tissues
Xylem
Lateral Vascular
root Phloem tissues
Vascular
Taproot cambium
Root hairs
(C) Root Epidermis
Root apex with (dermal tissue)
apical meristem
Cortex
Root cap
Pericycle Ground
(internal tissues
meristem)
Endodermis
Phloem
Vascular
tissues
Xylem
Root hair
(dermal tissue)
Primary wall Middle lamella Simple pit Vascular
cambium
Primary wall
Secondary wall FIGURE 1.2 Schematic representation of primary
and secondary cell walls and their relationship to
Plasma membrane
the rest of the cell.
(A) Dermal tissue: epidermal cells (B) Ground tissue: parenchyma cells
Primary cell wall
Middle lamella
(C) Ground tissue: collenchyma cells (D) Ground tissue: sclerenchyma cells
Primary cell wall
Sclereids
Nucleus
Fibers
(E) Vascular tisssue: xylem and phloem
Bordered pits
Simple
Secondary
pits Sieve plate
walls
Nucleus
Companion
cell
Sieve
areas
Sieve plate
Primary walls
End wall perforation
Tracheids Vessel elements Sieve cell Sieve tube element
(gymnosperms) (angiosperms)
Xylem Phloem
Plant Cells 5
FIGURE 1.3 (A) The outer epidermis (dermal tissue) of a THE PLANT CELL
(cid:2) leaf of welwischia mirabilis(120×). Diagrammatic representa-
tions of three types of ground tissue: (B) parenchyma, (C) Plants are multicellular organisms composed of millions of
collenchyma, (D) sclerenchyma cells, and (E) conducting cells with specialized functions. At maturity, such special-
cells of the xylem and phloem. (A© Meckes/Ottawa/Photo ized cells may differ greatly from one another in their struc-
Researchers, Inc.)
tures. However, all plant cells have the same basic eukary-
otic organization: They contain a nucleus, a cytoplasm, and
subcellular organelles, and they are enclosed in a mem-
brane that defines their boundaries (Figure 1.4). Certain
sues are illustrated and briefly chacterized in Figure 1.3. structures, including the nucleus, can be lost during cell
For further details and characterizations of these plant tis- maturation, but all plant cells beginwith a similar comple-
sues, seeWeb Topic 1.3. ment of organelles.
Vacuole Tonoplast Nucleus
Nuclear
Peroxisome envelope Nucleolus Chromatin
Ribosomes
Rough
Compound endoplasmic
middle reticulum
lamella
Smooth
endoplasmic
Mitochondrion reticulum
Primary cell wall
Plasma membrane
Middle lamella
Cell wall Golgi body
Primary cell wall
Chloroplast
Intercellular
air space
FIGURE 1.4 Diagrammatic representation of a plant cell. Various intracellular com-
partments are defined by their respective membranes, such as the tonoplast, the
nuclear envelope, and the membranes of the other organelles. The two adjacent pri-
mary walls, along with the middle lamella, form a composite structure called the
compound middle lamella.
6 Chapter 1
An additional characteristic feature of plant cells is that the bilayer. As a result, the fluidity of the membrane is
they are surrounded by a cellulosic cell wall. The following increased. The fluidity of the membrane, in turn, plays a
sections provide an overview of the membranes and critical role in many membrane functions. Membrane flu-
organelles of plant cells. The structure and function of the idity is also strongly influenced by temperature. Because
cell wall will be treated in detail in Chapter 15. plants generally cannot regulate their body temperatures,
they are often faced with the problem of maintaining mem-
Biological Membranes Are Phospholipid Bilayers
brane fluidity under conditions of low temperature, which
That Contain Proteins
tends to decrease membrane fluidity. Thus, plant phos-
All cells are enclosed in a membrane that serves as their pholipids have a high percentage of unsaturated fatty
outer boundary, separating the cytoplasm from the exter- acids, such as oleic acid (one double bond), linoleic acid
nal environment. This plasma membrane(also called plas- (two double bonds) and α-linolenic acid (three double
malemma) allows the cell to take up and retain certain sub- bonds), which increase the fluidity of their membranes.
stances while excluding others. Various transport proteins
embedded in the plasma membrane are responsible for this Proteins. The proteins associated with the lipid bilayer
selective traffic of solutes across the membrane. The accu- are of three types: integral, peripheral, and anchored. Inte-
mulation of ions or molecules in the cytosol through the gral proteinsare embedded in the lipid bilayer. Most inte-
action of transport proteins consumes metabolic energy. gral proteins span the entire width of the phospholipid
Membranes also delimit the boundaries of the specialized bilayer, so one part of the protein interacts with the outside
internal organelles of the cell and regulate the fluxes of ions of the cell, another part interacts with the hydrophobic core
and metabolites into and out of these compartments. of the membrane, and a third part interacts with the inte-
According to the fluid-mosaic model, all biological rior of the cell, the cytosol. Proteins that serve as ion chan-
membranes have the same basic molecular organization. nels (see Chapter 6) are always integral membrane pro-
They consist of a double layer (bilayer) of either phospho- teins, as are certain receptors that participate in signal
lipids or, in the case of chloroplasts, glycosylglycerides, in transduction pathways (see Chapter 14). Some receptor-like
which proteins are embedded (Figure 1.5Aand B).In most proteins on the outer surface of the plasma membrane rec-
membranes, proteins make up about half of the mem- ognize and bind tightly to cell wall consituents, effectively
brane’s mass. However, the composition of the lipid com- cross-linking the membrane to the cell wall.
ponents and the properties of the proteins vary from mem- Peripheral proteinsare bound to the membrane surface
brane to membrane, conferring on each membrane its by noncovalent bonds, such as ionic bonds or hydrogen
unique functional characteristics. bonds, and can be dissociated from the membrane with
high salt solutions or chaotropic agents, which break ionic
Phospholipids. Phospholipids are a class of lipids in and hydrogen bonds, respectively. Peripheral proteins
which two fatty acids are covalently linked to glycerol, serve a variety of functions in the cell. For example, some
which is covalently linked to a phosphate group. Also are involved in interactions between the plasma membrane
attached to this phosphate group is a variable component, and components of the cytoskeleton, such as microtubules
called the head group, such as serine, choline, glycerol, or and actin microfilaments, which are discussed later in this
inositol (Figure 1.5C). In contrast to the fatty acids, the head chapter.
groups are highly polar; consequently, phospholipid mol- Anchored proteinsare bound to the membrane surface
ecules display both hydrophilic and hydrophobic proper- via lipid molecules, to which they are covalently attached.
ties (i.e., they are amphipathic). The nonpolar hydrocarbon These lipids include fatty acids (myristic acid and palmitic
chains of the fatty acids form a region that is exclusively acid), prenyl groups derived from the isoprenoid pathway
hydrophobic—that is, that excludes water. (farnesyl and geranylgeranyl groups), and glycosylphos-
Plastid membranes are unique in that their lipid com- phatidylinositol (GPI)-anchored proteins (Figure 1.6)
ponent consists almost entirely of glycosylglycerides (Buchanan et al. 2000).
rather than phospholipids. In glycosylglycerides, the polar
The Nucleus Contains Most of the Genetic
head group consists of galactose, digalactose, or sulfated
galactose, without a phosphate group (see Web Topic 1.4). Material of the Cell
The fatty acid chains of phospholipids and glycosyl- The nucleus(plural nuclei) is the organelle that contains the
glycerides are variable in length, but they usually consist genetic information primarily responsible for regulating the
of 14 to 24 carbons. One of the fatty acids is typically satu- metabolism, growth, and differentiation of the cell. Collec-
rated (i.e., it contains no double bonds); the other fatty acid tively, these genes and their intervening sequences are
chain usually has one or more cis double bonds (i.e., it is referred to as the nuclear genome. The size of the nuclear
unsaturated). genome in plants is highly variable, ranging from about 1.2
The presence of cis double bonds creates a kink in the ×108base pairs for the diminutive dicot Arabidopsis thaliana
chain that prevents tight packing of the phospholipids in to 1 ×1011base pairs for the lily Fritillaria assyriaca. The