Plant Anatomy and Physiology (BIO3602)
Dr. Ng Lee Chuen
PPSTM Tel: 09-668 09-668 5050 Email:
[email protected]
Plant Anatomy and Physiology?
Plant Anatomy • ANA NAT TOMY: stud study y th the e structure of organisms. looking at cells, tissues and organs • In Inte tern rnal al str struc uctu ture re of plan plants ts,, esp especi ecial ally ly at at the the microsco ic level histolo . Histology: Study of the microscopic anatomy of cell and tissue of plants. Morphology: Study of the physical form and external structure of plants. • Pl Plan antt mor morph phol olog ogy y is us usef eful ul in th the e visu visual al identification of plants.
Plant physiology • The The s stud tudy y of of the the plan plantt funct function ion an and d proc proces esses ses occur occur in plant. life, • Plan Plantt phy physi siol olog ogy y is is a stud study yo off th the e plant way of life, which include various aspects of the plant lifestyle and , , nutrition, development, movement, irritability (response to the environment), organization, growth, and transport processes. • The The s stud tudy y from from the momen momentt of of con concep ceptio tion, n, zygo zygote, te, un until til the plant’s death.
Chapter 1: Introduction to Plant Cell Learning goal
• Understand the cells, tissues and organs in plant in relation to their functions in plant.
Learning outcomes 1. Describe the anatomy of plant in detail. 2. Explain the processes that involve by each cell structure in plant.
Plants- What are they?
Plants • Photosynthetic eukaryotes. • Is autotrophic. • Existed possibly as long as 1.6 billion years . • Is non-motile (grow toward essential resources eg: light, water and mineral nutrients). • Include angiosperms (flowering plants), gymnosperms (cone-bearing plants), ferns, and bryophytes (mosses & liverworts).
From smallest to largest plants
Individual plants of Wolffia arrhiza (atermeal!, 1"2mm #ide
$ymnosperms% the tallest, larges and the long"lived tress
verv ew of Plant Structure
Plant Cell
Animal cell
transport & modification
storage high energy carbs. contains DNA storage: pigments, acids,
structural support
respiration cell recognition, transport
photosynthesis
protein synthesis & transport of materials
A B
$ # " ! D C
Organelles in plant cells
Cell wall
primary cell #all " cellulose, hemicellulose, and pectin. secondary cell #all " inside primary cell #all, cellulose, hemicellulose, and lignin (complex alcohol polymer!. &ell #all is mainly cellulose% beta"1,'"glucopyranoside
Organelles in plant cells Cell wall
Organelles in plant cells Cell %all
Organelles in plant cells Cell %all • • • • •
•
Cell Wall is a rigid, non-living structure that surrounds the plant cell. It provides physical support for the cell. It determines the cell's shape. It protects the cell from osmotic expansion. Its most important components are cellulose (very strong), hemicelluloses (link together the cellulose fibers) and pectin (a gelatinous matrix). All plant cells have a "primary wall," some produce a stronger "secondary wall" as well.
Organelles in plant cells Cell %allmiddle lamella
'iddle lamella is an adhesive gelatinous unction bet#een the t#o primary #alls of t#o plant cells. It is cooperatively secreted by adoining cells.
Organelles in plant cells Cell %all plasmodesma • Small tubes that connect plant cells to each other, establishing living bridges between cells. – Allow certain molecules to pass directl from one cell to another. – These channels, penetrate the cell wall and are lined with plasma membrane, uniting all connected cells with essentially one continuous cell membrane.
Organelles in plant cells Plasma membrane
)protects the cell )allo#s cell recognition )regulates transport in and out of the cell )allo# for signal transfers )provides anchoring for other cell parts )provide a site for binding #ith other cells
Organelles in plant cells Chloroplast Chloroplasts
*esophyll
– are the organelles in which photosynthesis occurs. – absorb light energy and convert it to chemical energy. – grana (stacks of thylakoids)
&hloroplast
+ m
-uter membrane
hyla/oid ◦
◦
he membrane is impregnated #ith photosynthetic pigments (chlorophylls,carotenoids!. &hlorophyll is the green pigment that captures light for photosynthesis.
0troma $ranum
hyla/oid hyla/oid space
Intermembrane space Inner membrane
1 m
Organelles in plant cells Chloroplast lastids that capture light energy from the sun to ma/e food34 contain chlorophyll
•he plamid is a maor organelle. •lasmids are the site of manufacture and storage of important chemical compounds used by the cell.
Organelles in plant cells
Leucoplasts • Colorless plastids that store starch or oil • Found in tubers (e.g., Irish potatoes), roots, leaves, grains, fruits, and seeds.
Organelles in plant cells
Chromoplasts • Plastids that make & store carotenoid pigments. • Found in red & yellow peppers, oma oes, ower petals. • Carotenoid pigments are not water soluble, but it is fat soluble.
Organelles in plant cells Mitochondria • Double-membrane bound • Have their own ribosomes and DNA • Inner membrane-larger surface area • Sites of cellular respiration (process by which energy is released from fuels such as sugar)
Organelles in plant cells Mitochondria • Power-house of the cell - energy production – Cells re uirin lar e amounts of ener have numerous mitochondria. – Generates ATP from the oxidation of food molecules. – Requires oxygen and gives off carbon dioxide, called cellular respiration • With oxygen – aerobic • Without oxygen - anaerobic
Organelles in plant cells Nucleus
Organelles in plant cells Nucleus • Usually the most prominent organelle. • Contains the genetic material of the cell – DNA. – Chromatin is a complex of DNA and protein that is diffusely distributed in the nucleus. – DNA can be seen as chromosomes only during cell division. • Contains the nucleolus. – Nucleolar organizing area. – Contains the RNA molecules and proteins necessary for formation of ribosomes.
Organelles in plant cells Nucleus membrane ) 5ucleus is enclosed in a double layered membrane 6 7lso called the nuclear envelope.
) 0eparates the nucleus from the rest of the cell. ) 5uclear pores allo# for communication bet#een nucleoplasm and cytoplasm. 6 0mall openings in the envelope.
Organelles in plant cells
Ribosome • Sites of protein synthesis (translation). • Two subunits; one large and the other small. organelles. • Some free, some attached to the endoplasmid reticulum (ER).
Organelles in plant cells
Vacuoles • 80 -90% volume of cell. • Surrounded by vacuolar membrane: tonoplast (vacuolar membrane!
•
on a n: norgan c ons, organ c acids, sugars, enzymes and secondary metabolites. • Hydrolytic enzymes: protease, ribonucleases, glycosidases • Specialized protein storing vacuoles – protein bodies in seeds • Hydrolytic enzymes stored in lytic vacuoles
Organelles in plant cells
Cytoplasma / cytosol • Extends bet#een cell
membrane, tonoplast and nuclear membrane • Includes metabolically active as #ell as inactive particles – -rganelles 6 the small
membrane"bound components of the cell that allo# it to function – &ytosol 6 the a8ueous part of the cytoplasm outside of the other membrane bound organelles
Organelles in plant cells
Endoplasmic reticulum • Single unit membraned structure • Membranous sacs • Rough ER (has ribosomes associated with it) , Smooth ER (lacks ribosomes and is tubular)
Organelles in plant cells Functions of ER • Produces all lipids, proteins required for the synthesis of new cellular membranes (membrane factory). • Provides space for storage of synthetic product. eg. glycogen metabolic activities. • Plays a role in the origin of plasmodesmata. • Transport (a type of cell 'highway' system), intracellular exchange of materials. • Mechanical support to cytoplasm.
(!) differs from )!) in the follo%ing aspects :
Smooth ER
Rough ER
No ribosome, devoid of pores
Bears ribosomes and pores
Smooth
Rou h
Peripheral, may be connected to plasma membrane
Internal, may be connected to nuclear membrane
Synthesis glycogen, lipids and steroids
Synthesis protein
Has vesicles and tubules
Cisternae and a few tubules
Organelles in plant cells
Golgi apparatus •
Most abundant in meristematic and secretory cells.
•
Produce materials for export (secretion).
•
Polarity trans – exports vesicles).
•
Site of processing and packaging cellular components.
•
Vesiclesgolgi (cis-side) release processed sorted packaged re-released (trans face).
•
Active in synthesizing many cell component (carbohydrate).
Organelles in plant cells
'C)*B*D!( • Microbodies are a diverse group of organelles that are found in the cytoplasm of almost all cells, roughly spherical, and bound by a single membrane. • Two main type: peroxisomes and glyoxysomes • Peroxisomes: found in C3 and CAM lants, sites of photorespiration, removal of hydrogen from organic substrate, consuming oxygen. • RH2 + O2 R + H2O2 • Glyoxysomes: present in oil-storing seed • Glyoxylate cycle enzymes; convert stored fatty acid into sugar
Organelles in plant cells
Oleosomes • Oil accumulate in – oleosomes. • Also called lipid bodies or spherosomes. • Surrounded b half-unit membrane: phospholipid monolayer.
9ipid bodies stained #ith 0udan. 0ome cells may contain large amounts of storage lipids in vacuoles large : small. hese stain red #ith 0udan III.
The Cytoskeleton • Elaborate network of filaments that function to give strength, shape and movement to cells.
• Play fundamental role in: – mitosis, – meiosis, – cytokinesis, – wall deposition, – maintenance of cell shape and – cell differentiation
Cytos+eletal: 'icrotubules, 'icrofilaments and ntermediates "ilaments
• Microtubules & microfilaments: macromolecular assemblies of globular protein. Microtubules: • H ll w lin r 2 nm i m r. • Composed of polymer protein tubulin. • Tubulin monomer: heterodimer of two similar polypeptide chain (α and β-tubulin) • Each having ~55 000 dalton • 13 column tubulin monomer - protofilaments
Microfilaments
• Solid, 7 nm diameter, globular actin or Gprotein. • Compose of single polypeptide ~ 42 000 daltons. • Consist of two chain polymerized actin subunit – intertwine in a helical fashion. Intermediate Filaments
• Helically wound fibrous elements, 10 nm diameter. • Linear polypeptide monomer various types.
;unction of *icrotubules and *icrofilaments Cytos+eleton fleible tubular scaffold of microfilaments. • maintains cell shape and pro-ides support. • anchors organelles & enymes to specific regions of the cell. • contractility and mo-ement /amoeboid mo-ement0. • ntracellular transport trac+s for -esicle and organelle mo-ement by . Cytos+eleton components: • 'icrofilaments – solid protein /actin0 %hich is assembled at one end and disassembled at the other end. • ntermediate filaments ropeli+e fibrous proteins. – pro-ide structural reinforcement – anchor organelles – +eep nucleus in place
