Parts of Angiosperms

NATSCI II HANDOUT
I. Overview
 Plant biologists study two levels of plant architecture: morphology and anatomy.
• Plant morphology - study of the external structure of plants
• Plant anatomy - study of the internal structure of plants
 The focus of the discussion is the angiosperm plant (will not include plants from other divisions such as the moss, etc)
• Angiosperms (flowering plants) are the most diverse, widespread and ‘advanced’ among all plants.
- Characterized by flowers and fruits.
- Taxonomists divide angiosperms into two major taxonomic classes: monocots and dicots which possess either one or two seed leaves, respectively, in combination with other characteristics.
 A plant can be divided into two basic systems, a subterranean root system and an aerial shoot system (stems, leaves, flowers).
Each system depends on the other for survival of the whole plant.
- Roots depend on shoots for sugar and other organic nutrients
- Shoots depend on roots for minerals, water and support.
 Materials are transported throughout the plant by vascular tissues (continuous throughout the plant)
- Xylem transports water and dissolved minerals to the shoots.
- Phloem transports food from shoots to roots and other non-photosynthetic parts, and from storage roots to
actively growing shoots.
II. Roots
 Root structure is well adapted to: (a) anchor plants, (b) absorb and conduct water and nutrients, and (c) store food.
 2 major types of root systems:
• Taproot system (seen in many dicots) – has one large, vertical root (the taproot) that produces many smaller secondary roots; provides firm anchorage
Some taproots, such as carrots, and sweet potatoes are modified to store a large amount of reserve food.




• Fibrous root system (found primarily in monocots) – has a mat of threadlike roots that spreads out below the soil surface; provides extensive exposure to soil water and minerals
Roots are concentrated in the upper few centimeters of soil, preventing soil erosion.


 Root parts
1. Primary root- thickest part; grows downward
2. Secondary roots- arise from primary root; thinner; grows sidewards
3. Root cap- protects root; secretes mucilage that lubricates root for movement in soil; designed to drill soil guides root growth by perceiving gravity
4. Root hairs- small hair-like extensions; increase root’s surface area, increasing capacity to absorb water and minerals

1. Epidermis- outermost layer; for water and mineral absorption
2. Cortex- for water and mineral transportation to central cylinder of root thru diffusion; may also be used for food storage
3. Endodermis- develops root pressure for water movement
4. Pericycle- from where secondary roots branch

 Symbiotic associations:
• Mycorrhizae – symbiotic associations between roots and fungi wherein water & mineral absorption are enhanced by the fungi
• Root nodules – contain symbiotic bacteria that converts nitrogen to plant fertilizer
Fungi and bacteria get their food from roots in return.

III. Stems
 Stems are generally upright and above ground: (a) plant support and for elevation of leaves, flowers and fruits (b) place where buds and shoots generally develop (e) for transportation of fluids between the roots and the shoots in the xylem and phloem (f) storage of nutrients (g) production of new living tissue.

 Stem parts
1. Nodes- points where leaves are attached to stems
2. Internodes- stem segments between the nodes
3. Axillary bud- embryonic side shoot found in the angle formed by each leaf and stem; usually dormant
4. Terminal bud- bud on the tip of a shoot / stem; usually has developing leaves and a compact series of nodes and internodes

1. Epidermis- for protection from water loss, gas regulation and secretion of secondary metabolic compounds
2. Fibers and sclereids- supporting tissues
3. Pith- center of the stem and may function as food storage; transports nutrients to outer tissues in the plant
4. Apical meristem- area of cell division responsible for growth at tip; composed of tunica cells and corpus cells
5. Lateral meristems- areas of cell division that give rise to growth in girth
a. vascular cambium- give rise to secondary xylem and phloem
b. cork cambium- replaces the epidermis of roots and stems
6. Endodermis- store food; allows solutions to pass from vascular bundles to cortex
7. Pericycle- strengthens the stem; protects vascular bundles

 Stem modifications
Some plants have modified stems which are often mistaken for roots. There are several types of modified stems, each of which performs a specific function
a. Stolons/ Runners – horizontal stems where new plants grow; creeps above ground (eg. strawberry plant runners)
b. Rhizomes – horizontal stems growing underground; stores food (eg. ginger)
c. Tuber - usually a swollen rhizome; grows underground (eg. potato)
d. Corms – upright swollen stem covered with papery scales; grows underground; stores food (eg. gladiolus)
e. Bulbs – like corms but has leaf bases that are the ones that store food (eg. onions)
The trunk of a tree is a modified stem. There are other types of stem modifications aside from the ones listed above.

III. Leaves
 Leaves are commonly flat, broad and green to maximize its function in absorbing sunlight and transforming it into food
 Plant taxonomists use a variety of leaf characteristics to classify plants:
a. Basic leaf types
Simple leaf – Compound leaf –
has one blade attached to stem has a blade divided
into leaflets

b. Leaf shape- broadly lance-shaped, narrowly lance-shaped, obovate, ovate, etc

c. Leaf arrangement on stems- alternate (left), opposite (center), or whorled (right)





d. Leaf vein pattern- pinnate (left) or palmate (right)

e. Leaf margin- serrated, smooth with pointed lobes, smooth/ entire, smooth with rounded lobes

 Leaf parts
• External parts:
1. Blade- the entire leaf unit
2. Vein- vascular bundles (made up of xylem and phloem)
3. Apex- tip of the leaf
4. Base- part of the blade that is closest to the stem
5. Margin- term used to describe the edge of a leaf
6. Petiole/ stalk- connects the leaf blade to the stem
7. Stipule- tiny leaf-like structures that may or may not be present at the base of the petiole

1. Cuticle – waxy layer on the epidermis which reduces water loss and prevents disease-causing organisms from entering the leaf
2. Palisade layer- filled with chloroplasts and carry on most of the photosynthetic activity
3. Spongy mesophyll layer- temporary storage of sugars and amino acids; aids in exchange of gasses between leaf and environment
4. Stoma (plural-stomata)- pores at the lower epidermis; for gas exchange
5. Guard cells- regulate opening and closing of stomata thereby controlling gas exchange

 Leaf modifications
Leaves can be modified into several forms:
a. Spines – function to protect plant (eg. barberry)
b. Tendrils – support stems of climbing plants (eg. garden pea)
c. Bracts –may be green or brightly colored (mistaken for flowers) to attract pollinators (eg. bougainvillea)
d. Scale leaves – provide protection for buds and can be further modified for food storage (eg eastern redcedar)

IV. Flowers
 Flowers are the plants’ reproductive adaptation.
• Perfect flower – flower that has both male and female reproductive parts
• Imperfect flower – flower with either male or female parts
• Complete flower – flower with petals, sepals, stamen and pistil
• Incomplete flower – flower that lacks at least one of the parts of a complete flower
 Floral parts

Sterile parts (not involved in reproduction):
1. Sepals- modified leaves at the base of flower; usually green; enclose the flower before it opens
Calyx- made up of 2 or more sepals
2. Petals- lie inside ring of sepals; often brightly colored in animal- pollinated plants; lack bright coloration in wind-pollinated plants
Corolla- made up of 2 or more petals
Reproductive parts:
3. Stamen- male reproductive organ; consists of
a. Filament- stalk
b. Anther- terminal sac where pollen is produced
4. Pistil- female reproductive part; consists of
a. Stigma- receives pollen
b. Style- leads to the ovary at the base of the pistil
c. Ovary- protects the ovule
As ovules develop into seeds, ovary develops into a fruit.

Plant Divisions

KINGDOM PLANTAE:

Body type: multicellular with cell walls made of cellulose

Prokaryotic / eukaryotic: eukaryotic

Food consumption: photosynthesis (absorbs light)

Reproduction: both sexual and asexual

Environments: land and water

Hetero / Chemo / Autotrophic: Autotrophic

Characteristics: Plants have organs and organ systems. The leaves collect and absorb sunlight to convert to glucose. The leaves have a waxy coat on them to shield against water. The root system, which branches out, provides support and absorbs water. The stem provides support and the petal / flower / bud is the reproductive organ of the plant.

What distinguishes kingdom plantae from all the other kingdoms, is that the cells of kingdom plantae have cell walls made of cellulose that are used to support the plant. This cell wall is not a semi-permeable membrane and the cell cannot transport material and nutrients in and out of the cell walls. For this function there is the large central vacuole that stores water and chemicals for use inside of the cell. Another characteristic belonging only to kingdom plantae is their chloroplasts, the organelle that converts light energy into chemical energy inside the plant where the energy is stored as sugar. Their ability to convert inorganic matter (atmospheric CO2) to organic matter using photosynthesis keeps us humans in kingdom animalia alive.



Names of phyla:
-Filicophyta
-Sphenophyta
-Bryophyta
-Ginkophyta
-Coniferophyta
-Anthophyta

The naming of plants is governed by the International Code of Botanical Nomenclature and International Code of Nomenclature for Cultivated Plants

1. BRYOPHYTA
Mosses are small, soft plants that are typically 1–10 cm (0.4-4 in) tall, though some species are much larger. They commonly grow close together in clumps or mats in damp or shady locations. They do not have flowers or seeds, and their simple leaves cover the thin wiry stems. At certain times mosses produce spore capsules which may appear as beak-like capsules borne aloft on thin stalks.
Bryophyta do not have any true organs like stems, leaves or roots. They have tiny anchor-like rhizoids that keep them attached to the ground. They grow in shaded, moist places, like the rainforests.
Example : Physcomitrella patens(used as photobioreactor)
Sphagnum crisatum (as Christmas décor)
2. FILICOPHYTA OR PTERIDOPHYTA
A fern is any one of a group of about 12,000 species of plants. Unlike mosses they have xylem and phloem (making them vascular plants). They have stems, leaves, and roots like other vascular plants. Ferns do not have either seeds or flowers (they reproduce via spores).
Ferns are not of major economic importance, but some are grown or gathered for food, as ornamental plants, or for remediating contaminated soils. Some are significant weeds. They also feature in mythology, medicine, and art.
Ex. • Rumohra adiantiformis (floral fern), extensively used in the florist trade
• Microsorum pteropus (Java fern), one of the most popular freshwater aquarium plants.
• Osmunda regalis (royal fern) and Osmunda cinnamomea (cinnamon fern), the root fiber being used horticulturally; the fiddleheads of O. cinnamomea are also used as a cooked vegetable
3. SPHENOPHYTA
Consists of horsetails, which are basically stems. There aren't any noticeable leaves, and barely any roots.
Living species are commonly known as horsetails and typically grow in wet areas, with needle-like leaves radiating at regular intervals from a single vertical stem.
Ex. • Equisetum diffusum - Himalayan Horsetail
• Equisetum fluviatile - Water Horsetail
• Equisetum palustre - Marsh Horsetail

4. CONIFEROPHYTA
They are cone-bearing seed plants with vascular tissue; all extant conifers are woody plants, the great majority being trees with just a few being shrubs. Typical examples of conifers include cedars, douglas-firs, cypresses, firs, junipers, kauris, larches, pines, redwoods, spruces, and yews. They are the dominant plants over huge areas of land, most notably the boreal forests of the northern hemisphere,but also in similar cool climates in mountains further south

Ex. Norway Spruce (Picea abies)
Japanese Larch (Larix kaempferi)
Pinus strobus (Pine tree)

5. GINKGOPHYTA
Plants that are domestic to China and when reproducing, the females egg produces a very bad smell.
amily of gymnosperms which appeared during the Mesozoic Era, of which the only extant representative is Ginkgo biloba, which is for this reason sometimes regarded as a living fossil.

6. ANTHOPHYTA
The flowering plants or angiosperms are the most diverse group of land plants. The flowering plants and the gymnosperms are the only extant groups of seed plants. The flowering plants are distinguished from other seed plants by a series of apomorphies, or derived characteristics.

Sampaguita (Jasminum sambac)
Tulip (Liriodendron tulipifera)
Gumamela (Hibiscus rosa-sinensis)
Ilang-ilang (Canangium odoratum)
Sunflower (Helianthus annuus)
Eggplant (Solanum melongena)
Okra (Abelmoschus esculentus)
Ampalaya (Momordica charantia)
Tomato (Lycopersicon esculentum)
Apple (Malus domestica)
Calamansi (Citrus microcarpa)
Banana (Musa sapientum)
Mango (Mangifera indica)

Exercise 2 and 3

NOTE: Exercise 2 will only be conducted by Natsci2 students while Natsci2A will conduct exercises 2 and 3

Exercise2: DNA EXTRACTION

PROCEDURE
1. In the first container, mix 30 ml of water with 1 tbsp of salt.
2. In the 2nd container, mix 15 ml (3 tbsp) of water and 5 ml (1 tbsp) of liquid dishwashing soap.
3. Take 2 ml of the salt water solution from the first container and swirl it in your mouth for 30 seconds.
4. Spit the salt water and whatever contents are moving around in your mouth into the 3rd container.
5. Transfer about 1 ml of the spit into a test tube.
6. Add 1 ml (1 tsp) of the soap solution to the test tube and mix by gentle swirling for 1 min
7. After swirling, pour 15 mL (3 tbsp) of alcohol gently to the side of the test tube without mixing so that it floats.
8. After 1 minute, a cloud of bubbles will be seen at the bottom of the layer of alcohol and attached to it are transparent to whitish strands and that it is your DNA.
9. Remove your DNA and place it on a slide. Examine under a microscope. How does it look like?

QUESTIONS
1. Why should the alcohol be cooled first before using it the experiment?
2. Why do we need to use salt solution for swirling? Can’t we use other just plain water?
3. What is the purpose of the soap solution? How does the soap solution able to do it?
4. Is your DNA as seen in microscope the same as the theoretical double-stranded helix coil? Why?

EXERCISE 3. BACTERIAL STAINING

PROCEDURE
1. Swipe a toothpick in your cheek cells. Use another toothpick for your tongue and in between your finger toes.
2. Apply the swiped toothpick into the slide, air dry for 60 seconds.
3. Apply crystal violet. Wait for 60 seconds then rinse completely with water. Be sure that the bacteria is stained otherwise you have to repeat step 1 to 3.
4. Add gram’s iodine, then wait for 60 seconds.
5. Rinse completely with water.
6. Add safranin and wait for 45 seconds
7. Then rinse and dry over heat.
8. View the slide under microscope.

QUESTIONS
1. What is the color of gram-positive bacteria? How doest it differ with the color of gram-negative?
2. Why are the colors of the two bacteria different? How did it happen?
3. What is the purpose of the gram iodine?
4. Why do we need to dry the slide over a heat rather than just simply air-drying?