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