THE PLANT’S WAY OF LIFE

CHAPTER 5

PLANT

Fig. 5.1 Plant and its parts

Plants-eukaryotic, multi cellular, photosynthetic and non-mobile organisms-consists of various parts such as the root, stems, leaves and flowers- they make food- make oxygen- provide habitats and shelter for animals- help make and preserve soil- provide useful products for humans- beautify the environment

MODULE 1

The Plant as an Organism

Classification of Plants:

Angiosperms

- Flowering plants

- A typical plant body of an angiosperm is generally divided into two major systems ( Fig. 5.2 ):

root system- generally found below the ground

shoot system- all plant structures above the ground

A. General Body Plan

Fig 5.2 A Typical Plant Body

Two major groups of angiosperms:

• Monocots

• Dicots

Character Monocot Dicot

Leaf venation Parallel venation Netted venation

Number of seed cotyledon

One cotyledon Two cotyledons

Arrangement of Vascular Tissues-Stems-Roots

ScatteredForms ring

Forms ringForms in solid core

Petals In multiples of 3 In multiples of 4 or 5

Root type Fibrous root Tap root

Gymnosperms

- Cone-bearing plants

- any vascular plant that reproduces by means of an exposed seed, or ovule

ROOTS

- A cylindrical structure that originated from the radicle

- Typically a non- green structure usually found beneath the surface of the soil

Radicle- embryonic root

B. Parts of a Typical Plant

ROOTS

2 Major Root Types:

• Tap Root

• Fibrous Root

Tap Root

- Has distinct primary root

Fibrous Root

- The primary root is not well distinct from the secondary roots

Different Functions of Plant Roots:

• anchorage

• absorption

• support

• food storage

• photosynthesis

• reproduction

• protection

STEMS

STEM

- The continuation of the roots above the soil.

- Conducts water and minerals from the roots to other parts of the plant.

- Site for production and support of the leaves.

• node- swollen part of the stem where branches, buds and

leaves originate

• internode- portion between two nodes

• buds- Found at the tip of the stem, underdeveloped structures that typically give rise into leaves, shoots or flowers

• leaf axil- The angle formed between the stem and petiole of the leaf

Parts of the Stem

Some modifications in the stem of other plants:

a. Runners

- Allowed the stem to develop new roots and leaves wherein a node of the stem touches the soil

i. e. BERMUDA GRASS

b. Rhizomes

- underground, horizontal stem where new shoots develop

c. Tubers

- Have a short terminal portion of an underground stem that develop buds at the nodes

i. e. GINGER

i.e. POTATO

d. Bulbs

- Consist of small piece of stem that bears fleshy leaves

i.e.ONION

e. Corms

- short, bulky, vertical stem that can be differentiated from a bulb

i.e.GABI

f. Spines and Thorns

- sturdy, sharp-pointed structures for protection and modified outgrowth of the stem

g. Tendrils

- long, thin, coiling structures that attach the plant for support or adhere to surfaces

i.e.BOUNGANVILLA

i.e.GRAPES

LEAF

- An expanded, dorso-ventrally flattened structure attached to the node of the stem.

- Usually contains the green pigment(chlorophyll), others have yellow(xantophyll) and orange(carotene) used for photosynthesis.

a. Leaf Blade

- Also called as lamina (characterized by the presence of veins)

- thin, flattened part of the leaf

b. Petiole

- The cylindrical stalk or the narrow structure that supports the blade

c. Stipules

- Typically an outgrowth found at the base of the petiole in dicot plants

d. Ligules

- sheet-like extension at the base of the leaf blade of monocot plants

PARTS OF THE LEAF:

FLOWER

- Defined as a modified twig, derived from a bud.

- Highly adapted for reproduction.

Two Main Parts of a Flower:

• essential parts

•Accessory parts

( Pistil and Stamen)

(Sepals and Petals)

ESSENTIAL PARTS:

A. Pistil

- The female reproductive part of the flower.

- Consists of the following:

• stigma- Enlarged tip with opening for acceptance of pollen grains

• style- slender, tube-like part above the ovary where the

matured pollen grain traverses

• ovary - the swollen basal portion containing ovules

B. Stamen

- The male reproductive part of the flower.

- Consists of the following:

• anther- the site for pollen grain reproduction

• filament- the stalk that supports the anther

Accessory Parts:

A. Sepals

- Commonly green-colored, leaf-like parts that form the outermost floral whorl.

- Collectively known as calyx.

B. Petals

- Forms the floral whorl next to the sepals.

- Collectively known as corolla.

Complete flower

- Possesses the essential and accessory parts.

Incomplete flower

- Contains either only the female part or the male part of the essential parts.

• pistillate- contains the female part only.

• staminate- contains the male parts only.

POLLINATION

- The transfer of pollen grains from anther to the stigma of the same flower.

Meiosis- the process that the pollen grain mother

cell and the egg mother cell undergo.

• tube nucleus and two sperm nuclei- produced when the pollen grain haploids and

divides mitotically two times.

• eight-nucleated embryo sac- produced by the haploid egg cell.

Fertilization

- The union of the male and female gametes.

POLLINATION

The Plant’s Basic

Physiologic

Activities

The Water Transport Process in Plants:

1. Water and dissolved minerals from soil move into roots in the root hair region.

2. Nutrients then move through the cortex and into the stele via endodermis.

3. From the stele, most minerals move with water in the xylem, which is continuous throughout the plant.

Water Transport

- Governed by differences in water potential, the potential energy of water molecules.

• In order for the roots to absorb more water and minerals, large surface area is needed to be present in their surroundings.

• Water diffuses out of the plant during transpiration through the stomata.

Prepared by:

GROUP 2

Cueva, Juan Paolo

De Guzman, Lorenzo Miguel

De Guzman, Myquie Nicole