Plant Growth and Development Part I

Whole Plant

Organs

Macromolecules

Organelles

Tissues

Cells

Levels of Organization

Whole Plant

Organs

Macromolecules

Organelles

Tissues

Cells

Levels of Organization

Plant Cells

Differentiation in Cells➢ Refers to the process by which distinct

plant cells arise from precursor cells and become different than each other

➢ Unique adaptation of plants

Whole Plant

Organs

Macromolecules

Organelles

Tissues

Cells

Levels of Organization

Plant Tissues – Xylem and Phloem

= xylem•Transports water and minerals

from the roots to the plant parts

•Moves only in one direction

= phloem•Moves photosynthates (sugars)

throughout the plant

•Moves both directions

These internal tissues are also important for

supporting the plant….

http://www.fairchildgarden.org/EduProfDev/Leaf_anatomy.html

Movement of water through the plant: Transpiration

Heat

Stomata – microscopic openings, usually

on the bottom of a leaf, important for gas

exchange and transpiration

Vascular cambium

Vascular cambium

•Located between the xylem

and phloem

•Produces new xylem and

phloem tissue

•Responsible for increasing

stem diameter.

Phloem, Xylem and the Cambium Layer

Knowing the cambium layer is important when looking at wood boring insects

and disease – such as mountain pine beetle

Knowing the Cambium Layer is Important for Plant Grafting

Or, why leaving trees tied for too long or

Why letting the 13-year-old weed whip around trees

Is a bad thing…

XYLEM

PHLOEM

VASCULAR BUNDLE

http://www.fairchildgarden.org/EduProfDev/Leaf_anatomy.html

CAMBIUM

PITH

EPIDERMIS

Vascular Bundle Arrangement

Un

der

stan

din

g C

rop P

roduct

ion, S

tosk

opf.

, 1981

Monocot (grass) Dicot (broadleaf)

Whole Plant

Organs

Macromolecules

Organelles

Tissues

Cells

Levels of organization

Vegetative Organs (plant parts)

➢Stem➢Leaf➢Root➢Shoot➢Bud

Asexual (vegetative)

Reproduction

The Function of Stems

➢Mechanical support and display

➢Movement of water and minerals up to the leaves

➢Movement of photosynthates (sugars) to other parts of the plants

➢Asexual propagation

➢Storage

http://www.gimcracker.com/blab/archives/2002_12.html

Modified Stems

➢ Crown

➢ Stolon

➢ Rhizome

➢ Corm

➢ Bulb

➢ Tuber

➢ Spur

Can grow above

and below ground

Woody Stems

➢Shoot

➢Soft young stem with leaves

➢Twig

➢Dormant stem one year old

➢Branch

➢Stem over one year old

➢Trunk

➢Main stem of a woody plant

21

The Parts of a Woody Stem

Parts of a Plant Shoot

➢Leaf primordia

➢Shoot apex

➢The tip of the shoot

➢Axillary bud

Parts of a Plant Shoot

➢Node

➢Area on the stem where a leaf, another stem, or flower bud is located

➢Internode

➢Space between the nodes on a stem

Vegetative Buds➢A bud is an undeveloped

shoot that produces leaves and/or flower parts

Determining One Year’s Growth

A Plant’s Life Cycle – Annuals

➢Annuals

➢Completes life cycle in 1 year

➢Grow, mature, bloom, produce seed and die

➢ Summer annuals complete their life cycle in spring and summer

➢Winter annuals complete their life cycle during the fall and winter.

Usually easy to pull

out of the ground

Summer Annual Weeds

➢Black medic

➢Pigweed

➢Pineapple weed

➢Purslane

Winter Annual Weeds

➢Chickweed

➢Henbit

➢Penny cress

A Plant’s Life Cycle – Biennials

➢ Biennials➢Requires all or part of 2

years to complete its life cycle

➢Vegetative 1st year

➢Overwinters

➢ Flowers and fruits 2nd year

➢Bolting (flowering in one year) may occur in extreme environmental conditions

A Plant’s Life Cycle – Perennials

➢Perennials➢Live for many years

➢Woody➢Trees and shrubs

➢Herbaceous➢Die back to the ground

in Montana

What are the issues

with reading about

herbaceous perennials

on the Internet or in

popular publications?

How about leaves?

Dartmouth.edu

The inside

story

http://www.fairchildgarden.org/EduProfDev/Leaf_anatomy.html

Functions of Leaves

➢Food manufacture – photosynthesis

Functions of Leaves

➢Protection of delicate tissues like buds

➢Bud scales

➢Floral bracts

➢Sepals

➢Storage – Cotyledons, bulbs

Plant Identification Key

Blade (lamina)

Apex

Vein

Margin

Base

Petiole

Leaf

Structure

Types of Leaves – Venation

Monocot (grass) Dicot (broadleaf)

Types of Leaves – Simple Leaves

Types of Leaves – Compound Leaves

Opposite Whorled Alternate

Leaf Arrangement

Leaf Shapes and Margins

Plant Identification Key

Roots

➢Anchorage➢Nutrient and water absorption➢Storage➢Aerial support➢Propagation (sometimes)

➢Roots that are not growing cannot absorb nutrients

Cross Section of a Root➢ Root cap

➢ Protection

➢ Apical meristem region➢ Cell division

➢ Elongation➢ Pushes root through soil

➢ Differentiation➢ Root hairs and secondary

roots

➢ Root hairs➢ Absorb water and

nutrients

Roots

Modified Roots➢Swollen root

➢Prop roots

➢Radicle

Reproductive Organs

➢Flowers

➢Fruits

➢Flower buds

➢Seeds

Sexual Reproduction

Parts of a Flower➢Sepal

➢Usually green; protect the flower

when it is in bud

➢Petal➢Attract pollinators

➢Pistil ♀

➢Stigma➢Pollen falls and develops

➢Style➢Stalklike part between the stigma

and ovary

➢Ovary➢Enlarged part of the Pistil that

containing ovules

➢Stamen ♂

➢Anther ➢The part of the stamen that

contains the pollen

➢Filament➢Stalk of the stamen

Parts of a Flower

♀ - Pistil

Stigma

Style

♂ - Stamen

Anther

Filament

How about flowers . . .

♂ ♀

“My squash is putting out a lot of

flowers, but I am not getting any fruit…”

How about flowers . . .

♂ ♀

How about flowers . . .

➢Not all flowers have both male and female parts

➢Some plants may contain only male or female flowers

➢We will discuss this more in following classes

♀

♂

Composite Flowers

Inflorescence (Flower) Types

Plant Identification Key

Questions?