Plant Structure, Growth, and Development

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Slide 1

Plastic Plants?

The fanwort plant exhibits developmental plasticity, the ability to alter itself in response to its environment.

Developmental plasticity is more marked in plants than in animals.

In addition to plasticity, plant species have by natural selection accumulated characteristics of morphology = form that vary little within the species.

Slide 2

The fanwort has two types of leaves -- developmental plasticity

Slide 3

Concept 35.1: The plant body has a hierarchy of organs, tissues, and cells

Like multicellular animals, plants have organs composed of different tissues, which in turn are composed of cells.

Three basic organs evolved: roots, stems, and leaves.

They are organized into a root system and a shoot system:

Roots rely on sugar produced by photosynthesis in the shoot system.

Shoots rely on water and minerals absorbed by the root system.

Slide 4

Flowering Plant Morphology

Reproductive shoot (flower)

Apical bud

Node

Internode

Apical

bud

Shoot

system

Vegetative

shoot

Leaf

Blade

Petiole

Axillary

bud

Stem

Taproot

Lateral

branch

roots

Root

system

Slide 5

The Three Basic Plant Organs: Roots, Stems, and Leaves

Roots are multicellular organs with important functions:

Anchoring the plant

Absorbing minerals and water

Storing organic nutrients

Slide 6

A taproot system consists of one main vertical root that gives rise to some large lateral roots, or branch roots.

Adventitious roots arise from stems or leaves.

Seedless vascular plants and monocots have a fibrous root system characterized by many thin lateral roots with no main root.

In most plants, absorption of water and minerals occurs near the root hairs, where vast numbers of tiny root hairs increase the surface area.

Slide 7

Root Hairs of a radish seedling

Slide 8

Many plants have modified roots

Prop roots

“Strangling”

aerial roots

Storage roots

Buttress roots

Pneumatophores

Slide 9

Modified roots

Prop roots - support tall top heavy plants