[Notes] BOT1L - Introduction to Plant Sciences: Laboratory

1 BOT 1 L Notes by F5XS

Introduction to Plant Science: Laboratory

1595

Hans & Zacharias Jansen

1655

Robert Hooke

1667

Antony van Leeuwenhoek

1931

Evn Ruska & Max Knoll

invention of the first compound microscope found small “rooms” in a sliver of cork and called them cellulae (“little rooms”) made a microscope which made him see microbes, RBCs, sperm; used single-lens microscope made the prototype of the electron microscope

A microscope is an instrument that enables one to see parts of the specimen that the unaided eye cannot see.  the lenses of the microscope can enlarge or magnify  has a resolving power since it can show finer details  resolution is the ability of a microscope to distinguish two points as separate and unique  limit of resolution is the distance of two points to be identified  wherein is the light wavelength and is the numerical aperture, the amount of light that can enter the microscope o a light microscope is used in examining thin slices of the specimen mounted on a slide o a dissecting microscope / stereomicroscope gives a three-dimensional view of the specimen o other microscopes: o research microscope o camera microscope o microprojector An ocular micrometer is an instrument attached to the ocular with no known measurement. It is calibrated using a stage micrometer. In order to calibrate the ocular micrometer, the calibration factor must be obtained. This is done by using the formula

⁄

wherein

are the number of small divisions in the stage micrometer involved in the overlap and being the number of small divisions in the ocular micrometer involved in the overlap. The initial magnification is the number of times the image is magnified by the objective. It varies in objectives. The final magnification is the number of times the image is magnified by the ocular. This is constant (but depends on what ocular you’re using). Total magnification is just the product of the IM and the FM. Objective Scanner Low Power Objective High Power Objective Oil Immersion Objective

IM 4 10 40 100

FM X X X X

TM 4X 10X 40X 100X

The coarse adjustment and the fine adjustment are used to gain focus. The coarse adjustment is used to gain focus when observing under the scanner or the low



power objective while the fine adjustment is used to gain focus when observing under high power objective or the oil immersion objective. A parfocal microscope shows the specimen at focus even if you change the objective.

Modern Cell Theory  all living things are made up of cells  the cell is the structural and functional unit of all living things  all cells come from pre-existing cells by division  cells contain hereditary information that is passed on from cell to cell  all cells are similar in chemical composition  all energy flow of life occurs within cells

Organelles Size DNA Ribosome Metabolism

Prokaryotes not membrane-bound 1-10 µm circular 70S anaerobic or aerobic

Eukaryotes membrane-bound 10-100µm linear 80S aerobic

The plant cell is composed of the cell wall and the protoplast, the living component of the plant cell. The cell wall is made up of cellulose, the chloroplasts in the protoplasts contain the green pigment chlorophyll.

Location Shape Cell Wall Cell Wall Quality Function

Parenchyma young soft plant parts; all around the cell

Collenchyma young aerial plant parts; subepidermal

round

polygonal

varied fiber)

only has a primary wall

has an unevenly thickened primary wall

mainly composed of thick secondary wall

pectin

lignin and suberin

flexible support of young aerial plant parts

protection, support and strengthening

cellulose, pectin, hemicellulose photosynthesis, storage, repair, differentiation

Sclerenchyma hard woody tissues (sclerid

or

The middle lamella is a structure chemically made up of calcium pectate that glues together adjacent walls. Pits are discontinuity in the secondary wall where plasmodesmata passes through. Cytoplasmic streaming is the movement of the cytoplasm within the cell.

There are three types of pigments:  chlorophyll are green pigments found in chloroplasts  carotenoids are red-orange pigments found in chromoplasts



 anthocyanin are violet pigments found in the large central vacuole Chlorenchyma (Parenchyma associated) In Light

Chloroplast Chromoplast (Contains Carotenoids)

In Dark Protoplastid

Etioplast

Photosynthetic Storage Plastid

Amyoplast (Starch)

Leukoplast

Elaioplast (Fat)

Nonphotosynthetic

Proteinoplast (Protein)

Ergastic substances are non-living inclusions of the plant cell which are usually starch grains and crystals.  raphides are calcium oxalate crystals appearing as group of needles  cystoliths are calcium carbonate crystals appearing as sac of stones; found in Ficus elastica  druses are calcium oxalate star-shaped crystals found in Nerium oleander  rhombohedrons are calcium oxalate crystal shaped like a parallelogram  starch grains are ergastic substances that is the storage form of carbohydrates in most plants; found in Zea mays

The cell cycle is composed of two periods: the interphase and the division phase. The first gap (G1) phase of the interphase involves increase of cell size. Followed by Synthesis phase wherein the genetic material is replicated into two exact copies. The second gap (G2) phase involves protein synthesis. The division phase involves two processes: karyokinesis, division of the nucleus, and cytokinesis, division of the cytoplasm. Mitosis involves the production of daughter cells with the same genetic makeup as the parent cell; occurs in the vegetative or somatic cells in the meristems. Meiosis involves the production of sex cells or gametes; occurs in the sporangium. A single chromosome has two sister chromatids. The end of each chromatid is called a telomere. The part in the middle of the chromatids are joined by centromeres made up of kinetochore proteins. During anaphase, the spindle fiber, made up of kinetochore microtubules, connect to the centromeres. Alike chromosomes are called homologous chromosomes. A bivalent is composed of two chromosomes/univalent or four chromatids. A microsporocyte (pollen mother cell) is a specialized diploid cell that produces four haploid microspores at the end of meiosis.



Haploid cells are also called dyads Meiosis I is also called reductional division while meiosis II is also called equational division. Mitosis: Prophase → Metaphase → Anaphase → Telophase → Interphase Meiosis: Leptonema → Zygonema → Pachynema → Diplonema → Diakinesis → Prophase I → Metaphase I → Anaphase I → Telophase I → Prophase II → Metaphase II → Anaphase II → Telophase II

Leaf Vegetative Stem Shoot

Flowers

Plant Root

Reproduction

Fruits

Seeds The primary root, the first formed root, develops from the radicle of the seed embryo. Adventitious roots are roots that arise from other plant organs. The fibrous root of the monocot has a short-lived primary root and is replaced by numerous, long, slender lateral or branch roots. The taproot of the dicot has a well developed primary root that give srise to smaller lateral roots. Metamorphosed roots: 1] enlarged/fleshy roots for food/water storage 2] prop/brace roots for support 3] green roots for photosynthesis 4] pneumatophores for gas exchange


Introduction to Plant Science: Laboratory Protoderm

Epidermis Primary Xylem

Apical Meristem

Procambium

Primary Phloem Pith

Ground Meristem

Cortex

There are three regions on the root tip: cell division, cell elongation and cell maturation. The root hairs, whose surface area is increased for absorption, are usually found in the region of cell maturation. The root cap is the covering of the root apex. Immediately next to the root cap is the quiescent center. The cortex is the tissue under the epidermis. The stele is the collection of vascular tissues together with the pericycle, the, and the pith, if present. A protostele, present in the dicots, contains no pith while the siphonostele, present in the monocots, contains pith. A radial or alternate vascular bundle arrangement has alternating xylem and phloem. The pericycle is layer of cells undergoing differentiation and surrounding the xylem and phloem. The Casparian band is a band of suberized material impregnating the radial and transverse walls of the endodemal cells especially in roots. Exarch – where the metaxylem is towards the central core of the corss section while the protoxylem is away from it; the exarch development of plants is usually tetrarch The hypodermis is a differentiated sclerenchymatous tissue inder the epidermis of roots, some stems and pine leaf. Types of water transportation: 1] symplastic transport – through plasmodesmata 2] apoplastic transport – through cell wall 3] transcellular transport – though cell membrane

The stem is an elongated plant organ that forms the aerial axis on which lateral appendages (leaves, flowers and fruits) are attached.



The stem has nodes, where leaves arise, and internodes, areas between successive nodes. There are two buds of the stem, the axillary bud and the terminal bud. The terminal bud contains an apical meristem that elongates the plants and creates a hormone that prevents the growing of the axillary buds. The axillary buds give rise to lateral shoots. Lenticels, found in dicots, are elevated areas on the bark’s surface that functions for gas exchange and water loss. A monocot has, instead, leaf sheaths and no nodes nor internodes. In the single apical cell initial organization, the apical cell initial divides by mitosis yields the component cells of tissues in the stem. In the tunica-corpus organization, the tunica is the outermost with one or more layers of cells dividing anticlinally (perpendicular to surface). The corpus is a mass of inner cells that exhibits both anticlinal and periclinal division. A leaf primordium is a bulge formed by the first leaf that is initiated in the shoot apex. Cutin is a waxy substance coating the epidermis of dicots. If the vascular cambium, a meristematic region between the primary phloem and the primary xylem, is present, the vascular bundle is open. Otherwise, it is closed. The interfascicular region is a parenchymatous region between two vascular bundles. Endarch – where the protoxylem is towards the central core of the cross section while the metaxylem is away from it In monocots, the bundle sheath is a group of thick-walled cells that encloses the phloem and xylem.

Dicot Monocot

Epidermis Present Absent

Cortex and Pith Defined Undefined

Stele Eustele Atactostele



Zea mays cross section, 40X

Cucurbita stem cross section, 40X

Selaginella stem cross section, 40X

Cordyline stem cross section

Secondary Growth

Cambial

Vascular Cambium

Fusiform Initials (vertically oriented)

Secondary Xylem

Secondary Phloem

Diffused

Cork Cambium (Phellogen)

Ray Initials (horizontally oriented)

Vascular Rays

Periderm

Phellem (Cork Cells)

Phelloderm (Cork Parenchyma)


Primary Meristems Protoderm Ground Meristem


Dicotyledon Root Primary Secondary Tissues Meristems Epidermis Cortex Endodermis Pericycle

Procambium

Secondary Tissues

Cork Cambium

Phellem Phelloderm

Vascular Cambium

Secondary Xylem Secondary Phloem

Primary Phloem Primary Xylem

Growth Rings (Wood)  early wood / spring wood / sapwood – grows only during the rainy season  late wood / summer wood / heartwood – grows only during the dry season

Bark Wood

Periderm Cortex Primary Phloem Secondary Phloem Vascular Cambium Secondary Xylem Primary Xylem Pith

Xylem Tissue component elements  vessel elements  short and wide, thick-walled, larger in diameter, perforated end walls  conducts water and nutrients  tracheids  longer and more slender, lightly stained, smaller diameter  allows limited radial transport  fibers  fibrous, slender, with pointed ends, smallest diameter  functions for support  ray parenchyma  short, rectangular cells that functions for storage and radial transport o gymnosperms have no vessel elements Phloem Tissue component elements

9 BOT 1 L Notes by F5XS     o


phloem fibers – functions for support sieve tube elements – main conducting cells that conducts photosynthates companion cells – controls the sieve tube elements ray parenchyma – functions for storage and radial transport gymnosperms have sieve cells instead of sieve tube elements and albuminous cells instead of companion cells

Transverse Section

Tangential Section

Radial Section

Annona squamosa x-section stem, 10X

Pinus (G) macerated stem, 40X

Citrus, x-section root, 10X


Angiosperm macerated stem, 40X


Woody stem of Pinus



A leaf is a flattened, green, lateral appendage that carries out the functions of photosynthesis and transpiration.  phyllotaxy is the particular arrangement of the leaf attachment to the node of the stem  megaphylls are plants that form leaves that have an intricate venation pattern and a leaf gap  a leaf is made up of primary tissues  the cuticle is a waxy covering of the epidermis to prevent excessive water loss  the stomata are specialized epidermal cells that serve as passageways for carbon dioxide and water vapor  the mesophyll, the leaf’s ground tissue, comprises cells with many chloroplasts Leaf Morphology Dicot Monocot  the petiole connects the Petiole Presence leaf to the stem petiolate Sessile netted or parallel or  stipules are a pair of Leaf Venation reticulate striated green outgrowths from the Leaf Symmetry dorsi-ventral isobilateral node of the stem; not all plants have stipules  if the leaf has different dorsal and ventral surfaces, it is known as dorsiventral symmetry; otherwise, isobilateral symmetry  ligules are membranous structures with pointed ends that are distributed horizontally at the junction of the leaf sheath and lamina  auricles, found at the base of the blade, are thin, membranous, earlobe-like extensions Leaf Types  a simple leaf has only one leaf blade per petiole  a compound leaf has a blade that is divided into smaller units called leaflets that may or may not be joined by the petiolule to the petiole  a leaf with two opposite files of leaflets is a pinnately compound leaf



 a leaf that has a greater number of orders of pinnate leaflets is a polypinnate  a leaf that has leaflets extending from a common center is a palmately compound leaf

Type bulb bracts enlarged petiole bud scales lea tendrils vegetative leaves piny petiole pseudostem insect trapper

Metamorphosed Leaves Function Example food storage Allium cepa Bougainvillea spectabilis, Mussaenda colored leaves sp. for buoyancy Eichhornia crassipes bud protection Ficus elastica support Flagellaria indica asexual Kalanchoe pinnata reproduction protection Livistonia rotundifola additional support Musa sapientum traps insects Nepethes elata

Leaf Phyllotaxy  in alternate phyllotaxy, only one leaf arises per node  in opposite phyllotaxy, two leaves arise at every node  in whorled phyllotaxy, three or more leaves arise per node Dicot Leaf  the palisade mesophyll is a chlorenchyma that is columnar with intercellular space  the spongy mesophyll lies beneath the palisade mesophyll and do not form a definite shape  aerenchymas are large intercellular spaces between the spongy mesophyll  the primary phloem of the vascular bundle of the leaf is abaxial, located away from the axis, while the primary phloem is adaxial, located towards the axis  a stomatal crypt is a depression in the leaf of some plants beneath the stoma  trichomes are hair-like extensions of specialized epidermal cells located at the stomatal crypt Monocot Leaf  the bulliform/motor cells are inflated cells that are larger than the epidermis that shrinks and increases in size depending on the environment Gymnosperm Leaf: Xeromorphic characteristics of this leaf make the leaf thrive under conditions  the epidermis is overlain by a thick cuticle  the hypodermis lies below the epidermis that are thick-walled or sclerified  the vascular tissue has a ring of endodermis  the transfusion tissue that surrounds the xylem and phloem functions for storange and water conduction  a resin duct is composed of secretory cells that surround the resin canal



Pinus needle, x-section, 100X

Coffea sp. leaf, x-section, 100X

Nerium oleander leaf, x-section, 40X

Pinus insularis x-section diagram

Oryza sativa x-section diagram

Nerium oleander lamina portion diagram

Pinus leaf x-section diagram

Coffea leaf x-section diagram



Coffea lamina portion diagram

Photosynthesis involves the absorption of radiant energy by pigments inside the chloroplast and its conversion into chemical energy. Transpiration is the loss of water vapor through the stomata.

The flower is a structure similar to the vegetative shoot but greatly modified to accommodate the sexual reproductive cycle in angiosperms.  the four whorls of the flower are the sepals, petals, the male stamen, and the female pistil  the collective term for these, respectively, are calyx, corolla, androecium, and gynoecium  perianth is the collective term for both calyx and corolla and are sterile or non-essential  the pistil and stamen are fertile or essential  all four whorls are borne by a receptacle that is held up by a stalk called peduncle  a colored sepal is called a tepal  flower that blooms as only one flower is called a solitary flower while a cluster of flowers is called an inflorescence  a single member of an inflorescence is called a floret  a floret/flower that doesn’t have a pedicel, the stalk connecting to the stem, is sessile  located in the androecium are the filament and the anther which holds the pollen grains  the gynoecium contains the ovary at the base, the style and the stigma  the carpel is one of the components of the gynoecium in which ovules are found



 a complete flower composes all the four whorls; otherwise, it is incomplete  a perfect flower composes both essential parts; otherwise, it is imperfect  a plant that bears both male and female flowers is monoecious; dioecious when separate  an actinomorphically or regularly symmetrical flower has petals that are of the same size and radiate from a common center  a zygomorphically or irregularly symmetrical flower has central petals, the wings, from the standard/banner and the keel below  the flower is hypogynous if its ovary is superior, that is that the flower parts are below the ovary; otherwise, the flower is epigynous and the ovary is inferior Type Species  placentation is the manner on how catkin Acalypha hispada ovules are attached to the ovary corymb Jatropha podagrica cyme Jatropha hastate  a type of placentation in which the ovules are attached on a head/capitulum Tagetes erecta compartmentalized central axis is panicle Panicum maximum axile raceme Caesalpinia sp.  a type of placentation in which the spadix Anthurium sp. ovules are attached on the ovary spike Peperomia pellucida wall is parietal umbel Allium cepa  a type of placentation in which the ovules are attached on a central axis without compartments is free-central

 a fruit is a mature ovary of a group of ovaries which may or may not retain some additional floral parts  contains the fertilized ovule, the seed  parthenocarpy is a process of developing of fruits without fertilization  the cotyledon absorbs the endosperm and foot is stored there  seeds are protected by a seed coat that develops from the integuments of the ovule  the exocarp is the peel or the outermost layer  the mesocarp is the soft, juicy, and fleshy inner part  the endocarp encloses the seed  dehiscent fruits split open at maturity  a septum is a structure dividing a cavity into smaller compartments Types of fruits  a simple fruit develops from a single ovary  fleshy fruits  a berry is a fleshy fruit with succulent pericarp enclosing one or many seeds  a drupe is a simple fleshy, one-seeded fruit with a distinct mesocarp surrounding a very hard or stony mesocarp  a hesperidium is a fleshy septated berry with leathery exocarp; the bulk of its edible parts comprised of glandular hairs



 a pepo is a fleshy fruit or berry developed from an inferior ovary with its fruit wall being a hard rind formed from the fused receptacle and pericarp  a pome is a fleshy fruit with a cartilaginous endocarp and its receptacle adnate to the pericarp  dry, dehiscent fruits  a capsule develops from an ovary with two or more carpels that split open along narrow lines or pores  a pod or legume forms from one carpel that splits open on its two opposite sides  a loment is like a pod except that it breaks up into one-seeded segments  a silique develops from two or more carpels, the latter becoming separated from each other by a septum when mature  dry, indehiscent fruits  an achene derives from a one-loculed, superior ovary containing a lone seed attached at only one point  a cypsela develops from a one-loculed inferior ovary  a grain or caryopsis has a fused and indistinguishable pericarp and seed coat  a nut is a one-seeded fruit derived from a one-loculed ovary with a hard pericarp  a samara or key is a winged achene whose wings are flattened, papery tissue that develops from the ovary wall  a compound fruit comes from several fused ovaries Fruit Type Berry

Drupe Hesperidium Pepo Pome Capsule Pod/Legume Loment Silique Achene Cypsella Grain/Carypsis Nut Samara/Key

Common Name Ilang-ilang Guava Papaya Pili Mango Coconut Pomelo

Scientific Name Cananga orodata Psidium guajava Carica papaya Canarium ovatum Mangifera indica Cocos nucifera Citrus sp.

Apple Okra Castor Bean Mahogany Patani

Malus sylvestris Abelmschus esculentus Ricinus communis Swietenia mahogani Phaseolus lunatus

Strawberry

Fragaria × ananassa

Rice Corn Cashew

Oryza sativa Zea mays Anacardium occidentale

 a multiple fruit is composed of many fruitlets which developed from flowers arranged in an inflorescence



 an aggregate fruit is developed from a single flower inflorescence with many ovaries gathered on a common receptacle Phaseolus lunatus (patani) parts  the hilum is the scar left on the seed coat by the detached funiculus  the micropyle appears as a pin-sized opening at one end of the hilum  the raphe is a ridge-like structure found at the other end of the hilum; a mass of tissue between the chalaza and funiculus Ricinus cummunis (castor bean) parts  the caruncle is a spongy structure originating from the seed coat and conceals the micropyle Zea mays (corn) parts  the mesocotyl found between the epicotyl and hypocotyl is the region of attachment of the cotyledon  a scutellum is a shield-like cotyledon in grass embryo  the coleoptiles is a tissue that forms the outermost covering of the epicotyls  the coleorhizae is a tissue that arcs over the radical serving as a protective covering

[Notes] BOT1L - Introduction to Plant Sciences: Laboratory

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