2. Nature of a plant system: A Plant body
or system
• made up of organs
• made up of tissues
• made up of cells
• made up of organelles
• made up of molecules
• made up of elements
Cell: basic unit of an organism
3. Figure 1. Basic parts of a plant cell
Figure 1. Basic parts of a plant cell
4. Organelles and other components of a Plant Cell
1. Cell Wall: for cell support and regulation
Components of the cell wall:
A. Middle lamella: outermost layer, glue that
binds adjacent cells, composed primarily
of pectic polysaccharides.
B. Primary wall: wall deposited by cells before and during
active growth; comprised of pectic
polysaccharides, cross-linking glycans/
hemicellulose; cellulose and protein; All
plant cells have a middle lamella and primary wall.
C. Secondary Wall: some cells deposit additional layers inside
the primary wall. This occurs after growth stops or
when the cells begin to differentiate or specialize; is
mainly for support and is comprised primarily of
cellulose and lignin.
5. Organelles and other components of a Plant
Cell…
2. Plasma or Cell membrane: Cell boundary;
selectively permeable (some can pass, some
cannot); separates the organelles and cell parts;
bilayer of phospholipids with inserted protein.
3. Nucleus: contains the genetic materials for
heredity (DNA)
6. Organelles and other components of a Plant
Cell
4. Cytosol/ cytoplasm: gel-like matrix within the
cell in which other structures are embedded; refers
to the cell contents inside the membrane.
5. Mitochondrion: powerhouse of the cell; sites of
cellular respiration (process by which energy/ ATP is
released from fuels such as sugar).
7. Organelles and other components of a Plant
Cell
6. Ribosomes: sites of protein synthesis
(translation).
7. Endoplasmic reticulum: site of lipids and
membrane synthesis (smooth ER); also contains
ribosomes (rough ER) for protein synthesis;
function in transport (a type of cell 'highway'
system) and support.
8. Organelles and other components of
a Plant Cell
8. Peroxisome: membrane sac containing
enzymes for metabolizing waste products from
photosynthesis, fats and amino acids.
9. Glyoxisome: membrane sac containing
enzymes for fat metabolism, especially common
in seeds
9. Organelles and other components of a
Plant Cell
10. Golgi apparatus: site of processing and
packaging cellular components, especially for
export.
11. Microtubules: involved in the cell cytoskeleton
(for support), cell movements (cilia, flagella) and
cell division (spindle).
12. Plasmodesmata: “cell bridges/ tunnels”
10. Organelles and other components of
a Plant Cell
Parts unique to plants:
13. Plastids: double membrane-bound organelles
in plants which contain their own DNA (in nucleoid
region) and ribosomes.
Types of plastids:
A. Proplastid: small, precursors to the other plastid
types, found in young cells, or actively growing
tissues.
11. B. Chromoplast: non-photosynthetic, colored
plastid; give some fruits (tomatoes, carrots) and
flowers their color.
C. Amyloplast/ leucoplast: colorless and starch-
storing plastid.
D. Etioplast: plastid whose development into a
chloroplast has been arrested (stopped). These
contain a dark crystalline body, prolamellar body,
which is essentially a cluster of thylakoids in a
somewhat tubular form.
12. E. Chloroplast:
– site of photosynthesis (energycapture).
– They contain photosynthetic pigments including
chlorophyll, carotenes and xanthophylls.
– The chloroplast is packed with membranes,
called thylakoids. The thylakoids may be
stacked into pancake-like piles called grana
(granum, singular). The "liquid" material in the
chloroplast is the stroma.
14. Plant tissue system
• Tissue: made up of different types of cells
– Meristematic tissues: actively dividing and
differentiating cells found in growing point
– Apical meristem: shoot or root apex; upward and
downward growth;
– Lateral meristem: sides of roots or stems;
sideward growth
– Intercalary meristem: between internode of
grasses; regrowth of cut grasses
15. • FF
Figure 2. The development and differentiation of the apical meristem to different
types of tissues
16. • Permanent tissues: mature, fully differentiated
cells
– Simple tissues: only one type of cell
– Parenchyma: thin-walled cells, makes up a large
portion of many plant organs, seat of plant activities
– Collenchyma: thick-walled elongated cells, support
cells/ mechanical support during growth
– Sclerenchyma: thick-walled highly specialized, heavily
lignified, mature or non-living: Fibers: long & tapered
Sclereid: short & irregular; gritty texture (chico)
17. Complex tissues: more than 1 type of cell
– Phloem = sieve tube + companion cells + ray cells
+ fiber cells + parenchyma cells
– Xylem = tracheids + vessel element + fiber cells +
parenchyma
18. Parts of the plant body
• Shoot: above ground structures; central axis
with appendages
• Root: below ground structures
21. General anatomical regions of a plant body
• Epidermis: outermost layer, serves as
protection
• Cortex: next layer to epidermis
• Pericycle: found in root branches; layers of
cells adjacent to the cortex, found in roots.
• Vascular bundle:
• Phloem: through its sieve tubes, transport
food/dissolved sugar; passage way
• Xylem: water passage way
• Pith: hollow opening in the center of the stem; absent
in most roots.
22. Anatomical regions of a leaf
• Epidermis:
– “skin”/ outer covering; a continuous “skin” that covers
both sides of a leaf.
– It is formed by a single layer of transparent,
interlocking cells, which are covered by the cuticle,
designed to protect the leaf’s internal tissues from
excessive dehydration.
– Numerous openings called stomates (stomata).
– The majority or all of which are located on the
undersides of leaves, perforate the epidermis and
permit a two-way exchange between the atmosphere
and the inside of the leaf of such gases as carbon
dioxide, water vapor and oxygen.
23. Anatomical regions of a leaf
• Mesophyll:
– cells containing plastids especially chloroplasts;
– contains the food-producing machinery of the
leaf, the chloroplasts. These are the specialized
bodies imbedded within the cytoplasm of the
mesophyll cells which contain chlorophyll, the
green pigment which is the basis of
photosynthesis.
24. Anatomical regions of a leaf
• Vascular bundles (veins):
– for translocations; composed of specialized
strands of tissue which are located about halfway
between the upper and lower surfaces of the leaf
and consists of two kinds of tissue:
» thick-walled, woody xylem cells which conduct water and
provide mechanical support (Xylem)
» thin-walled phloem cells which serve as pipelines for
liquid foods (Phloem)
Together they form a conducting system which, branching
from one or several main veins, permeates the entire leaf.
26. Anatomical regions of a leaf
• The Vascular vessels
– Xylem: translocates water and mineral ions from
the roots to the stem and the leaves
– Phloem: translocates inorganic substances and
sugars from the leaves to the parts of the plant
the need them, e.g flowers, fruits and roots
27. Anatomical regions of a leaf…
• Lignification:
– the process in which lignin wax is being laid down on
the inside of cell walls, resulting in death, but not
necessarily dysfunction, of the cells.
– Also, for the same reason, used as a generic term to
describe the process when woody plant tissues
harden.
• Lignin:
– a complex carbohydrate polymer making up about 25% of the
wood in trees.
– It is also found in the cell walls of sclerenchyma tissues and
vessels, fibres and tracheids at maturity.
– It increases the strength of such tissues.
28. Life cycle of a plant
Source: Bareja, B. and Caasi, D.R. (2014)
30. Parts of a grass
Source: Bareja, B. and Caasi, D.R. (2014)
31. Parts of a plant seed
Source: Bareja, B. and Caasi, D.R. (2014)
32. Stem
• Stem:
– important for translocation (transport of sugar,
minerals and water);
– supports the leaves, connects the leaves and
roots;
– provides storage
• Buds: embryonic stems
• Arrangements: Alternate, opposite or whorled
• Position: terminal, lateral, accessory, or adventitious
• Nature of organs: leaf, flower or mixed
• Structure and growth pattern: single upright or prostate
branched “creepers”
33. Modified stem
Tendril:
– a specialized stem, leaf or petiole with a threadlike shape
that is used by climbing plants for support and attachment,
generally by twining around whatever it touches;
– does not have a lamina or blade, but can photosynthesize;
– can be formed from modified shoots, or modified leaves.
Stem tendril:
• located on opposite side of the stem to that of the foliage leaf on
the same node;
• may be branched or bear small leaves
• Rhizome: enlarged stem for storage and reproduction;
– with nodes and internodes; leaf buds grow upward
34. Modified stem
• Tuberous stem:
– enlarged stem for storage and reproduction; with bud
eyes (where foliage grows)
• Corm: vertically growing enlarged stem; with nodes and
internodes
• Runners or stolons: Long slender branches which arise from
the base of the stem growing horizontally (grasses) or
obliquely downwards.
• Phylloclades/ cladodes: flattened or cylindrical green stems
• Offshoots or suckers: daughter plants arising from a main
plant
• Bulbils: found in the axils of leaves, similar to underground
stem with cork, has parenchymatous ground tissue with
scattered vascular bundles
35. Leaf
• Leaf:
– Principal photosynthetic organ
– Absorbing organ for chemical and micronutrients
(ectodermata)
– Transpiration organ (water regulation, stomatal
opening/closing)
– As storage organ
– As plant propagule
– As ornamental for pigment color (aesthetics)
– Modified leaf:
• Bulbs: vertically-growing underground shoots with
fleshy leaves and a short stem
36. Flower
• Flower:
– reproductive organ of the plant;
– gives rise to the fruit; Plant structures serving for
sexual reproduction with seeds as the final product.
– Produced by spermatophytes or flowering plants
(seed plants).
• Two large groups of spermatophytes
– Gymnosperms: evolutionarily older and more primitive group
(systematically), no class on their own but enclose two real classes
that do not have the same ancestors: (1) conifers and (2)
cycadeans
– Angiosperms: usually seen as the original flowering plants, do all
belong to just one class, represent the overwhelming majority of
species
37. Flower
• Parts of a flower
–Perianth: calyx and corolla
• Calyx: sepals (protects growing bud)
• Corolla: petals (attracts pollinators)
– Androecium: the male reproductive
organ comprising of the stamens with
each stamen consisting of a filament
and an anther
38. Flower
• Staminodes: sterile stamens
– Gynoecium: the female reproductive organ which includes
the carpel which is made up of the ovary and a stigma
(contain one or more ovules)
Apocarpy or choricarpy:
- each carpel forms a pistil
Coenocarpy:
- several carpels form a pistil; one or more carpels may be
combined to a pistil (ovary, style, and stigma)
--Pistil: made up of enlarged ovary (with embryo sac), a
columnar style, and distal stigma (receives the pollen)
39. Flowers
• Morphology of the androecium and
gynoecium:
– Hypogynous: the perianth is attached to the
receptacle below the pistil
– Perigynous: the perianth and stamens are borne
on the rim of a concave structure in the
depression of which the pistil is borne
– Epigynous ovary: blossom seems to arise upon or
above the ovary
40. Flowers
• Types of plants depending on sexes:
– Androgynous or hermaphroditic: flowers that
contain both androecium and gynoecium; e.g.
papaya
– Monoecious: both male and female flowers live
on one plant; e.g. corn (tassel is the male part,
and the silk is the female part)
– Dioecious: plants with male and female flowers
borne on separate plants; e.g. squash
41. Flowers
• Types of flowers:
– Complete flower: all four floral organs (sepal, petal,
stamen and pistil) are present in the same flower
structure, e.g. Gumamela or China rose (Hibiscus
rosa-sinensis).
– Incomplete flower: lacks any one or more of these
parts; e.g. grasses mainly wind-pollinated and are
incomplete, lacking both sepals and petals. Relying
on wind to accomplish pollination, there is no need
for these organs to attract pollinators.
42. Flower
• Perfect or bisexual flowers:
– flowers that contain both sexual flower parts
(stamen and pistil)
• Imperfect or unisexual flowers:
– contain either stamen or pistil only (regardless
of whether they lack sepals or petals)
– Staminate flowers (male flower): bear stamens
only
– Pistillate flowers (female flower): bear pistils
only
43. Flower types affecting pollination
• Plants with flower synchrony based on the maturation of the
male (stamen) and female (pistil) flower parts
– Dichogamous: when the two organs mature at different
time.
– Protandrous flowers (n. protandry), as in carrots:
are those in which the stamens mature ahead of
the pistils so that by the time that the stigma
becomes receptive, the pollen grains within the
same floral structure are already shed.
– Protogyny is the reverse of protandry: The stigma of
protogynous flowers, as in the water lilies
(Nymphaea spp.), becomes receptive while the
pollen grains are still immature
44. Flower types affecting pollination
• Autogamous:
– plants self pollinate within the same flower
(autogamy);
– Further divided based on their opening or closing
during the pollination period (pollination is the
transfer of pollen grains from an anther to a stigma):
• Chasmogamous flowers (n. chasmogamy): are open during
the period of pollination and are generally cross-pollinated
• Cleistogamous flowers (n. cleistogamy):
– flowers do not open during the period of pollination
and thus these plants are largely self pollinated.
– Ex. tomato, lettuce and some rice species.
45. Fruit
• Fruit:
– a part of a flowering plant that derives from specific
tissues of the flower, one or more ovaries, and in
some cases accessory tissues; the means by which
these plants disseminate seeds;
– results from maturation of one or more flowers, and
the gynoecium of the flower(s) forms all or part of the
fruit;
– contains the seed needed for dispersal and survival of
the species.
46. Fruit
• There are three general modes of fruit
development:
1. Apocarpous fruits: develop from a single flower
having one or more separate carpels, and they
are the simplest fruits.
2. Syncarpous fruits: develop from a single
gynoecium having two or more carpels fused
together.
3. Multiple fruits: form from many different flowers
47. Kinds of fruits:
• Simple fruits:
– can be either dry or fleshy, and result from the
ripening of a simple or compound ovary in a
flower with only one pistil
• Dry fruits:
– Dehiscent: opening to discharge seeds
– Indehiscent: not opening to discharge seeds
– Achene: strawberry
– Capsule: Brazil nut
– Caryopsis: wheat, rice
– Cypsela: achene-like from individual florets in a capitulum; e.g.
dandelion
48. Kinds of Fruits
• Drupe: coconut, walnut
• Follicle: single carpel, opens by one suture; milkweed
• Legume/pulse: pea
• Loment: indehiscent legume
• Nut: hazelnut, acorn
• Samara: elm
• Schizocarp: carrot seed
• Silique: radish
• Silicle: shepherd’s purse
• Utricle: beet
49. Kinds of Fruits
• Simple fleshy fruits:
– part or all of the pericarp (fruit wall) is fleshy at maturity
• Berry:
• simple fruit created from a single ovary. The ovary may
be compound, with several carpels, e.g. tomato;
– Other berries:
» Pepo: berries where the skin is hardened, ex.
Cucurbits
» Hesperidium: berries with a rind and a juicy
interior, ex. citrus
» Drupe/ stone fruit: drupe
50. Kinds of Fruits
• Aggregate fruit or etaerio:
– develops from a single flower with numerous simple pistils;
– from single flowers that have multiple carpels which are not joined
together;
– each pistil contains one carpel, e.g. Raspberry
• Multiple fruit:
- one formed from a cluster of flowers (called an inflorescence).
- Each flower produces a fruit, but these mature into a single mass,
- e.g. Pineapple
• Accessory fruit: some or all of the edible part of accessory fruit is not
generated by the ovary.
51. Kinds of Fruits
• Parthenocarpy:
– where fruits set without fertilization (in some
species), may or may not require pollination but
most seedless citrus fruits require stimulus from
pollination to produce fruit.
• Stenospermocarpy: seedless bananas and grapes are
triploids, and seedlessness results from the abortion of
the embryonic plant that is produced by fertilization,
requires normal pollination and fertilization.
• Seed dispersal: by animals, wind, water, or explosive
dehiscence.
52. Roots
• Functions of the root system
– Anchorage and support in the soil
– Absorption of plant nutrients and water o Plant
propagules for some crops
– Nitrogen fixation (legumes)
– Storage of water and carbohydrates
– Soil conservation (soil erosion control)
53. Roots
• Types of root systems
– Fibrous: numerous, similar sizes, no central
primary root, makes shallow penetration in the
soil. e.g. monocot roots
– Tap: one central primary root with several
branches, makes deep penetration in the soil. e.g.
dicot roots
54. Roots
• Other root classification
– Adventitious roots: arise from the stem
– Storage
– Aquatic
– Brace, and
– Aerial
55. Roots
Modified and specialized roots
• Buttress roots:
– Large roots on all sides of a big bottomed tree or
shallow-rooted tree
– Typically are found in nutrient-poor rainforest soils
and do not penetrate to deeper layers
– Prevent the tree from falling over (hence the
name buttress) while also gathering more
nutrients
56. Roots
• Tuberous roots
– enlarged tap roots for storage , e.g. carrot originated
from Afghanistan), historically white or purple, orange
pigment is Beta carotene (used by the body to make
Vitamin A)
– Modern carrot has 75% beta-carotene than historical
carrot (>20 genes affect pigmentation in carrot)
– e.g. radish (has sulphur-based chemicals)
– e.g. Pachyrrizus erosus or sinkamas (23 kilos weight
of sinkamas dug in Ilocos March 2010)
– e.g. Ipomoea batatas or sweet potato (Native to
South America, domesticated at least 5000 years ago)
e.g. Dioscorea esculenta or lesser yam or tugi (With
purple pigments or anthocyanin)
57. Roots
• Prop or stilt roots
– adventitious roots on trunks or branches
– The adventitious prop roots help to support and
securely anchor this shrub in the mud and loose sand
of tidal waters, also provides aeration
– Lenticels:
• provide gas exchange and an additional source of oxygen for
the submersed roots are highly hydrophobic and prevent
water penetration into the aerenchyma system during the
high tide
• Pneumatophores (air-bearing/ breathing roots) or
pneumatorrhiza: located above water level or exposed at
low tide
• Aerenchyma tissues: aerial root projection
allowing gas exchange (aerenchyma tissues), e.g.
rice.
58. Roots
• Root nodules: enlargements in roots which
harbor nitrogen-fixing bacteria such as
Rhizobium, found in legumes, e.g. Pea plant
– Root nodules develop as a result of a symbiotic
relationship between rhizobial bacteria and the root
hairs.
– The bacteria recognize the root hairs and begin to
divide, entering the root through an infection thread
that allows bacteria to enter root cells,, which divide
to form the nodule.
59. • Mycorrhiza:
– fungi and root symbiosis or mutual
relationship; Plant provides the fungus with
carbohydrates, (e.g. glucose and sucrose)
by translocation. Fungal mycelia provide
higher water and mineral absorbtive
capacity (large surface area, mycelium: root
ratio).
60. References
Bareja, B. and Caasi, D.R. (2014). Lecture
Manual in Crop Science 1: Principles of
Crop Production. Mindanao State
University, General Santos City, Philippines
Dagoon, J.D. 2000. Crop Production Technology.
A specialized Course. Rex Book Store
