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Crop Plant Anatomy


drop plant Anatomy is the study of plant
parts and their function crop plant anatomy is the first unit of study
because one of the primary objectives of the course is to provide you with a
basic crop production vocabulary knowledge of plant anatomy is essential
in communication among farmers entomologists pathologists weed
scientists or anyone involved in crop production farm management specialists
local seed and fertilizer dealers herbicide specialists extension agents
and consultants all need to communicate about factors affecting plant growth in
order to convey accurate information and make the right decisions my knowledge of
crop Anatomy is essential remember if you are going to understand the whys
behind production practices you must know the parts of the crop plant and
understand the functions of these parts the first item for study is the section
entitled the plant cell you should study the general features of a plant cell be
able to identify them and describe their functions remember we are only briefly
reviewing the anatomy of the cell and are emphasizing only the major cell
parts and their function you should now stop the VCR study the section on the
plant cell in your text and then return to the VCR for further tutoring the cell wall is located on the outside
of the cell the plasma membrane a semipermeable membrane is located
immediately inside the cell wall the nucleus is the large globular body
containing most of the hereditary material of the cell the long strand
like parts shown here make up the endoplasmic reticulum and the small disc
shaped bodies on its surface are ribosomes both the ribosomes and
endoplasmic reticulum are involved in protein synthesis the cytoplasm is the
liquid or gel like material of the cell the chloroplasts found in the cytoplasm
is a principal type of plastid that contains chlorophyll the chloroplast is
the site of photosynthesis in the plant cell a vacuole also found in the
cytoplasm as a storage region for cellular materials the vacuole regulates
water pressure within the cell and maintains the proper cell rigidity a
mitochondrion is a site of aerobic respiration which is the main source of
energy for cellular metabolism and growth dik Tia somes
appear as curved strands and are associated with cell wall formation now
let’s move on to the section on seed and seedling anatomy after you study this
section you should be able to identify the parts of grass and legumes seeds and
seedlings and describe the functions of these parts this is a very important
section in crop anatomy it covers plant parts that will be
frequently used when estimating quality of seed and when discussing seedling
growth and crop management practices since many field related problems are
linked to poor seed quality an understanding of seedling emergence and
crop performance is Nessa you should now stop the VCR study the
section on serial carry abscess anatomy in your text and then return to the VCR
for further tutoring let’s now discuss serial carry OPS’s
anatomy using wheat and corn carry op sees the carry OPS’s is the botanical
name for the cereal kernel a brush of hair is usually found on wheat kernels
of many varieties but may be absent or different among different kinds of wheat
brush characteristics are often used to identify and differentiate between wheat
varieties the brush of hair is absent on the corn kernel instead the top of the
carry OPS’s has a dent in it this dent is formed because of the soft starch in
the center of the kernel shrinks more in the drying process than the flinty hard
starch along the edges the pericarp is the outer tissue of the kernel and
serves mainly as protection for the carry abscess the pericarp is ovary
tissue which means that the kernel is a ripened ovary this is in contrast to a
true seed which is a ripened ovule the all your own layer includes the few
cellular layers that surround the endosperm of the kernel this layer can
be either colorless or colored and secretes important enzymes for
germination dent corn has both starchy and flinty endosperm the starchy or soft
endosperm is located on the interior and the flinty are hard endosperm is usually
located in the perimeter of the corn kernel the wheat kernel also has
endosperm that is often referred to as gluten endosperm this gluten is a matrix
of starch and protein that gives bread dough its stretching ability allowing
the dough to rise corn does not have the types of protein or gluten that causes
the dough to be as stretchy as wheat rye and triticale dough the skew tell’em
often referred to as the cotyledon is the embryo area of the kernel corn
and wheat have only one cotyledon per seed and therefore are called
monocotyledonous plants the coleoptile is leaf like material that protects the
embryonic leaves and shoots that make up the epicotyl the apical meristem is also
known as the growing point after germination future development of the
stem and leaves will come from here the skew teller node is where the skew
tell’em is attached to the embryo axis the axis is the line connecting the
epicotyl with root tissue the embryonic root found in the lower part of the
embryo axis is called the radical surrounding the radical as a protective
sheath known as the colio raisa during germination the radical elongates and
breaks out of the kernel leaving a rupture the colio raisa seals off this
rupture to prevent disease from entering the kernel the development of a black
layer occurs in the corn carry OPS’s the black layer is an absent layer that
prevents further growth of the kernel and indicates physiological maturity a
black layer is not noticeable in the wheat kernel the final part is the tip
fastening the kernel to the plant as you studied the figure showing corn and
wheat kernels in your text you should have noticed how similar the parts are
for the carry OPS’s of the cereal crops now we’ll continue with the section on
cereal seed germination and seedling establishment your study goal for this
section is to be able to identify seed and seedling parts and know their
functions during germination and emergence a study of this anatomical
information will give you a better background to troubleshoot field
production problems occurring during the early stage of plant
development you should now stop the VCR and study the section on serial seed
germination and seedling establishment in your text then come back to the VCR
for further tutoring let’s look at the sequence of steps in
germination and emergence of corn within the first two days after planting the
pericarp imbibes water becoming soft and elastic the kolya raisa elongates
slightly and emerges from the pericarp at two to four days after planting the
radical then breaks through the kolya raisa and becomes anchored in the soil
five to seven days after planting the coleoptile elongates and several lateral
roots called seminal roots form at the kernel site
the radical together with the seminal roots are called the primary root system
and is the main root system for the first three weeks of growth the first
internode of the stem called the Meza caudal elongates and continues until the
coleoptile emerges from the soil surface seven to fourteen days after planting when the coleoptile emerges the Meza
caudal ceases to elongate as you study the wheat and corn germination and
emergence sequences in your text notice that the Meza caudal may elongate in
some cereal species and may not in others it elongates in corn and oats but
usually not in wheat barley or rye this structures elongation plus the
sword-like shape of the coleoptile are some of the reasons why corn can be
planted at greater depths after the coleoptile emerges from the soil the
young leaves break through turn green and begin to photosynthesize coronal
roots also called crown or adventitious roots develop immediately below the soil
surface these coronal roots are the secondary root system of grasses and
become the principal absorbing roots after about three weeks of seedling
growth the growing point or apical meristem is located just above the
uppermost node also called the coleoptile er node
the growing point remains below the soil surface for approximately 30 days it is
this structure that indicates whether replanting is necessary after a cereal
crop has been damaged by an adversity such as hail or insects the following
steps will help you in learning how to dissect a corn seedling and locate the
growing point if the seedlings are big and have a lot of roots you may want to
prune them next split the stem in half lengthwise using a razor blade it is
usually easier to start at the bottom or root end of the seedling open the stem
and place it under the dissecting microscope look for the light colored
structure resembling a pyramid at the tip of this structure is the growing
point ask the instructor to help you if you have difficulty will continue now
with the section on legumes seed Anatomy be sure to study this section so that
you know the parts of the legume seed and their functions you should now stop
the VCR study the section on legume seed anatomy in your text and then return to
the VCR for further tutoring soybeans and alfalfa are two common
legumes notice the vast difference in the pod shape and size even though both
pods are actually ovary tissues the seed characteristics however are very similar
the radical hi picado and epicotyl are the embryonic root stem and leaf tissues
together they form the embryo area of the seed the location of the embryo area
just inside the seed coat makes it vulnerable to possible damage from rough
handling during harvesting or processing if the embryo area is damaged the
seedling will be abnormal or weakened and may not emerge after planting the
other parts of the seed are the micropyle the hilum the cotyledon and
the testa their functions are described in your text the rubbery elastic outer
seed covering called the testa can be removed using your fingernail or a
dissecting meal at this point the soybean seed can be split into two
halves each half is a cotyledon and therefore legumes are called
dicotyledons plants look closely at each cotyledon if care is taken when
splitting the seed the intact embryo will normally be attached to one of the
cotyledons the epicotyl hypocotyl and radical can now be identified the
epicotyl is made up of the yellow leaves that will become the first true leaves
of the plant after emergence the epicotyl is attached to the hypocotyl
at the cotyledon airy node the hypocotyl is stem tissue that elongates pulling
the cotyledons toward the soil surface during germination
in the area between the hypocotyl and radical the tissue changes from stem
tissue into root tissue at this point the radical begins
the radical becomes the primary root of the plant you should note that the
growing point in legumes seedlings also called the apical bud is located at the
uppermost bud during the life of the plant the location of the growing point
within the seed is between the hypocotyl and epicotyl soybean seeds differ from
corn seeds in several ways soybean seeds have a high picado but
corn does not corn kernels have a coleoptile and colio raisa
but soybean seeds do not additionally the seed tissue does not contain part of
the ovary as in the pericarp of a corn kernel the soybean seed contains two
cotyledons but corn has only one cotyledon called the stew tell’em soybean seeds contain approximately 20%
oil and 40% protein corn kernels contain approximately 60% carbohydrates 4% oil
and 12% protein the next section for study is entitled legume germination and
seedling establishment you should now stop the VCR study this section in your
text and then return to the VCR for further tutoring let’s look now at the germination
sequence for soybeans the testa allows water to be imbibed by the seed the seed
swells and becomes elastic hormones stimulate the growth of the embryo the
radical elongates and ruptures the testa and then elongates through the soil the
hypocotyl then begins to elongate pulling the cotyledons toward the soil
surface the curved upper portion of the hypo caudal is called the hypo cotyledon
Airy arch and it straightens when the seedling emerges the testa usually falls
off the cotyledons and remains in the soil as the hypocotyl straightens the
cotyledons unfold allowing sunlight to reach the young leaves of the epicotyl
the leaves turn green and begin to photosynthesize the cotyledons will also
turn green after receiving sunlight and photosynthesize for several days
following emergence the first vegetative leaves to appear after soybean emergence
are you know folio late a leaf having a single leaflet then the tri folio late
leaves begin to form they consist of three leaflets attached to a petiole
swollen not like nodules become visible on the legume roots these nodules
contain bacteria called Rhizobium which convert nitrogen to a form available for
plant use axillary buds are present at each node above the soil surface these
buds can result in vegetative growth such as branches or reproductive growth
such as flowers the apical bud or growing point is the topmost bud on the
stem and is enclosed and the youngest developing leaf new stem growth develops
from the apical bud growth can resume from axillary buds
if the apical bud is destroyed in a few of the legume species such as
the pea the high picado does not elongate instead it has hypogea
emergence in which the cotyledons remain where planted additionally the epicotyl
elongates and pushes the growing point above the soil surface affecting
emergence remember most legumes have epithelial emergence in which the
cotyledons are pulled above the soil surface during germination
however grasses such as corn and small grains and certain legumes have high
pudgy illumination in which the cotyledons remain below the soil surface
you should next study the section on plant leaves in your text note that you
should learn the leaf parts of broadleaf plants and grasses you should also learn
the functions of the parts the first section for study is leaf anatomy you
should now stop the VCR study the section on leaf anatomy in your text and
then return to the VCR for further tutoring as you studied this section on leaf
anatomy he should have noted that leaves arise from nodes on the main stem or
branches the major functions of leaves are photosynthesis and gas exchange with
the atmosphere leaves may be classified as being parallel veined or netted
veined this grass leaf has parallel veins in which the veins run parallel
throughout the length of the leaf this Legum leaf has netted veins in which the
veins have multiple branching forming a lateral Network note the internal
structure differences between the leaves of dicotyledons our dicot plants and
monocotyledonous or monocot plants both dicots and monocots have a layer of
epidermal cells acting as protection for the other cells of the leaf the
epidermis is covered with a cuticle or wax like material in addition to
providing protection for the epidermis the cuticle helps maintain an adequate
amount of internal water in the leaf by preventing the evaporation of water both
dicot and monocot leaves have mesophyll cells in which photosynthesis takes
place but only dicots have palisade cells arranged side by side near the top
leaf surface to catch the sunlight the dicot leaves spongy parenchyma cells
have large pores between them allowing for gas transport throughout the leaf
the translocation system or transport system in monocot and dicot leaves is
made up of the xylem and phloem water and minerals are translocated from the
plant roots through the stem and throughout the leaves in the xylem
sugars and other materials are transported from the leaves to other
plant parts through the phloem the stoma are openings in the epidermis of the
leaves and are surrounded by guard cells guard cells regulate the opening and
closing of the stoma which control the rate of gas exchange with the atmosphere
with the ability for gas exchange with the air ready translocation of water and
other materials and the efficient arrangement of cells containing
chloroplasts the leaf has a very efficient arrangement for its principal
function of photosynthesis the next section on leaf morphology will discuss
the external parts of leaves it is important that you learn these parts
because they are essential in properly identifying crops and weed species you
should now stop the VCR study the section on leaf morphology in your text
and then come back to the VCR for further tutoring leaf morphology refers to the outward
appearance and structure of crop leaves leaf morphology is especially useful in
identifying species of plants in subsequent units you will need to know
how to recognize differences in the various leaf parts in order to identify
many of the important plant species some plant leaves are pubescent this means
they have hair like structures on the surface other plant leaves are glabrous
or without pubescence pubescence may protect leaves against small insects and
may also slow the loss of water from the leaf note in the figure labeled parts of
a grass leaf in your text that a grass leaf consists of a sheath collar and
blade the sheath is fastened to the stem at a node and extends up enclosing a
section of the stem the junction of the stem and blade is the collar region
depending on the species or variety the blade of grasses may be of different
widths and links or may be at different angles from the horizontal leaf collars
may be continuous or divided may vary in width or may be inconspicuous two
different structures may be located on the inside of the collar region the
league Ewell and Oracle League gills may vary in shape and size and may be
membranous or paper-like hairy or may not be present at all
Oracle’s may vary from long and claw-like to short to absent the
arrangement of leaves in the leaf buds or leaf venation may be folded or rolled
folded ver Nation usually results in a flattened leaf bud and rolled ver nation
in a more cylindrical leaf bud legume leaves maybe you know folate
having one leaflet or blade per leaf the uniformly flat is usually attached to
the stem or branch by a petiole legumes leaves may also be try folio late
having three leaflets here a petiole you’ll fastens the leaflet to the
petiole the petiole then attaches to the stem or branch some plants have multiple
leaflets with more than three leaflets per leaf some leaves terminate with a
tendril of Viney like structure stipules may be found where the petiole attaches
to the main stem different plant species have stipules that vary in shape and
size they may range from prominent narrow to hairlike let’s now study the
sections on functions of stems and stem anatomy the primary objectives in this
section are to identify the anatomical parts of the stem and to describe the
functions of the stem parts you should now stop the VCR study the sections on
stem functions and stem anatomy in your text and then return to the VCR for
further tutoring stems perform some very important
functions these functions include translocation of water and mineral
solutes from the roots to other plant parts translocation of sugars and other
synthesized food from the leaves to other plant parts support of other plant
organs all above-ground growth including leaves floral structures and branches
originated from buds produced at the stem nodes stems may function as storage
organs as in sugarcane stems that contain chlorophyll manufacture some
carbohydrates stems may also in some species be used to propagate new plants
the diagram of a longitudinal section of a dicot stem in your text shows the
internal structures of the stem the location of the primary phloem outside
of the xylem is a common characteristic of both dicots and monocots synthesized
food is conducted from the leaves to other plant parts chiefly through the
living cells of the phloem the xylem vessels are non living cells water and
mineral solutes are conducted from the roots to other parts of the plant
through the xylem the epidermis is made up of cells that protect the inner cells
of the stem the pith cells found in non hollow stems provide storage of food
materials in the plant an important point to note about a dicot stem is that
it has a vascular cambium layer that forms a ring within the stem with phloem
on the outside and xylem on the inside this cambium layer gives rise to new
phloem and xylem and therefore the legumes stems can increase in stem
diameter by cell division in monocots stems however there is no cambium and
therefore any increase in diameter of the stems
results from cell enlargement note again that the phloem is to the outside and
the xylem is to the inside of the stem there are two types of monocot stems one
is called a stock which has vascular bundles scattered throughout the ground
parenchyma of the stem the other stem type is a comb in which vascular bundles
are scattered in a ring of ground parenchyma the center of a calm stem is
hollow crops with calm type stems are often used as bedding material for
livestock providing the animal with a light fluffy resting place the next
section for study is the modified stems we usually think of stems as being
somewhat upright or vertical performing the functions discussed in the previous
unit some crop species have modified stems that perform the functions of
vegetative propagation and spreading the area of a single plant you should now
stop the VCR study the section on modified stems in your text and then
return to the VCR for further tutoring four kinds of modified stems are
illustrated in your text a stolen is a horizontal stem that grows above the
soil surface new shoots can form from each node and each of these shoots can
produce a new plan rhizomes are horizontal stems that grow below the
soil surface new shoots are plants can also form from the nodes on the rhizomes
stolen if Aris and rhizome attest plans are usually considered to be sod forming
in nature sod forming species create a carpet like stand and are often grown in
areas such as grass waterways to reduce the amount of soil erosion a third kind
of modified stem is a tuber the most common example is a potato note that
there is the possibility of a new chute developing from each node or eye on the
potato the hep-lock arm as found in timothy is the fourth example of a
modified stem after timothy has been cut for hay or after a long winter
carbohydrates from the haplit corm are used to furnish energy for regrowth from
the buds at the crown of the plant the next section for study is entitled plant
roots the objectives of this section are to identify the various parts of plant
roots and to describe the functions of the parts roots anchor the plant in the
soil absorbed minerals and water from the soil and transport water and
minerals to the plant stem where it will be transported to other plant parts
through the xylem you should now stop the VCR study the section on plant roots
in your text and then return to the VCR for further tutoring the plant roots let’s review some
important points root hairs are single-celled extensions of the root
epidermis and developed primarily in the zone of maturation root hairs form new
root growth most of the absorption of water and minerals is in this area of
new root growth new root growth occurs primarily in moist well aerated soil
let’s now study the development of the total root systems of crop plants note
that many legumes and other dicotyledons plants have tap root systems that may be
3 to 5 feet or more in length an alfalfa plant that is several years old may have
a tap root that is ten to thirty feet deep depending on soil type and other
factors the root system of an annual legumes such as soybeans may be only
about five feet deep and branched to the extent that it appears almost fibrous
grass roots are said to be fibrous because instead of having a main root
they form a network of roots from the crown area of the plant the depth of
grass roots ranges from about two feet for some sod forming species to more
than five feet for large grass plants such as corn the fibrous root system of
grasses makes some good species to grow as cover crops for erosion control the
last section for study is the section on grass and legumes in fluorescence the
word inflorescence refers to the flowering parts of the plant you should
learn the parts and types of grass and legumes inflorescences and how they vary
among crops the information in this section is important and necessary to
the understanding of yield plant breeding practices and plant
identification you should now stop the VCR study the introductory remarks and
the parts of a grass floret in your text and then return to the VCR for further
tutoring the first topic of review under this
section will be parts of a grass floret the grass floret or grass flower can be
defined as the Lima and palea and everything that lies in between a
typical young grass floret will have a Lima palea and male or female
reproductive structures an older mature floret however will have a Lima palea
and Colonel the grass floor it is normally perfect which means that it has
both male and female parts in the same flower the male part called the stamen
is made up of anthers and filaments the female part called the pistil is made up
of the stigma style and ovary therefore you should logically guess
that it would be self pollinated unless some additional mechanism exists to
prevent it while the grass florid is considered perfect due to its
reproductive components it is also incomplete because it is missing the
Corolla or petals it’s important to remember that the fertilized ovule and
the ovary develop into the carry OPS’s or Colonel the male parts of the floret
have usually disintegrated by the time the carry OPS’s matures corn is an
example of a mono asia’s plant meaning that the plant has imperfect flowers but
both male and female flowers are on the same plant the corn tassel contains male
flowers and the ear chute has female flowers a dioecious plant also has
imperfect flowers but male and female flowers are located on separate plants
the next topic for study is the grass spikelet the parts of the spikelet are
frequently used in identifying plant species or in discussing components that
determine seed yield you should now stop the VCR study this section in your text
and then return to the VCR for further tutoring the picture and diagram of the wheat
spikelet in your text may be used to study the various parts of a grass
spikelet note that the spikelet consists of the two glooms and everything in
between in wheat the glooms enclosed three or more florets attached to a
central stem called the red Killa note that the number of developed florets per
spikelet varies with the species for instance oats generally have two florets
per spikelet while orchard grass generally has many developed florets per
spikelet developed spikelets or kernels per spikelets also may be influenced by
environmental factors such as weather and soil fertility
the next topic for study is parts of a legume flower study this section in your
text and then come back to the VCR for further tutoring the figure in your text shows a closed
and open lagoon flower when the bee visits a closed flower during its search
for nectar the keel is tripped exposing the staminate column and thus opening
the flower this tripping action dusts the bee with pollen and when the bee
visits another flower cross-pollination can occur
let’s now dissect a legume flower note the visible parts of this flower from a
sweet pea the calyx is made up of five fused sepals the Corolla is made up of
the standard petal two wing petals and two fused petals that form the keel
petal when the standard petal is removed followed by the wing petal and then the
keel petal the reproductive parts are exposed the stamen is made up of anthers
attached to filaments there are nine filaments fused to form the staminate
column and one filament that is free the removal of the anthers filaments and
staminate column exposes the stigma style and ovary of the floret the
splitting of the ovary exposes the ovules that are ready to be fertilized
the anthers produce pollen grains that contain the reproductive cells the sweet
pea flower is a typical legume flower but it is several times larger than the
flowers of normal crop legumes such as the soybean and alfalfa the peanut
flower is a typical legume flower with one exception after pollination and
fertilization the flower develops a Jennifer or pig which elongates and
enters the soil this Jennifer produces a pod containing seed the next section for
study is in fluorescents types note that we are only going to discuss four basic
types of inflorescences commonly found in agricultural crops you should now
stop the VCR this section in your text and then
return to the VCR for further tutoring in the spike in fluorescence the
spikelets are directly attached or sessile to the central axis of the
inflorescence this central axis is called the Reyes note that the point of
attachment of each spikelet is a node on the rei’kas rye and barley spikelets
differ somewhat from wheat but there in fluorescence type is also a spike
note that the six rode barley spike has one florida per spikelet and three
spikelets Piraeus node giving an appearance of six rows of Florence per
spike the two rode barley has one floor at four spikelet and only one fertile
spikelet Piraeus node giving an appearance of two rows of Florence per
spike the second type of inflorescence we are studying is called ray seam and
fluorescence several legume species such as sweet clover fall into this category
unlike spike in fluorescence ray seam flowers are not attached directly to the
rei’kas each ray seam floret is attached to a pedicel it is this pedicel that
then attaches to the rei’kas the third type of inflorescence is the panicle
type the spikelet usually contains two florets the primary and the secondary
spikelets may contain one to several Florence depending on the species and
environment in a panicle the spikelet is attached to a pedestal that is attached
to the panicle branch it is the panicle branch that is then attached to the
reyes of the inflorescence the final type of inflorescence we will
study is called head in fluorescence two examples would be red clover and
sunflower these two heads look different but they
have something in common in the red clover head the flowers are clustered
and attached to an enlarged shortened receptacle in the sunflower head
there are ray flowers and disc flowers that are also attached to an enlarged
shortened receptacle be sure to carefully study all of the
information presented in the text and in other sources after you have completed
your study you should be able to take the self-evaluation test at the end of
the chapter in your text this is the end of the study of crop plant anatomy
please rewind this tape before returning it to the lab monitor

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