Plant Structure, Growth, and Development

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Slide 10

Modified Roots

Pneumatophores - “air roots” enable root systems to capture oxygen

Slide 11

Modified Roots

Buttress roots - support tall trunks of some tropical trees “like butresses.”

Slide 12

Stems = organs consisting of nodes & internodes

Nodes, the points at which leaves are attached.

Internodes, the stem segments between nodes.

An axillary bud is a structure that has the potential to form a lateral shoot, or branch.

Apical bud, or terminal bud, is located near the shoot tip and causes elongation of a young shoot.

Apical dominance helps to maintain dormancy in most nonapical buds.

Slide 13

Many Plants have Modified Stems

Rhizomes

Bulbs

Storage leaves

Stem

Stolons

Stolon

Tubers

Slide 14

Leaves = the main photosynthetic organs

Leaves generally consist of a flattened blade and a stalk called the petiole, which joins the leaf to a node of the stem.

Monocots and eudicots differ in the arrangement of veins, the vascular tissue of leaves:

Most monocots have parallel veins.

Most eudicots have branching veins.

Slide 15

Simple vs. Compound Leaves

(a) Simple leaf

Compound

leaf

(b)

Doubly

compound

leaf

(c)

Petiole

Axillary bud

Leaflet

Petiole

Axillary bud

Leaflet

Petiole

Axillary bud

Slide 16

Some plant species have evolved modified leaves that serve various functions

Slide 17

Some plant species have evolved modified leaves that serve various functions

Tendrils

cling

Spines “prickly” Photosynthesis is

carried out mainly by the fleshy stems

Storage Leaves succulent

plant leaves store water

Reproductive leaves

Little plantlets fall off

and take root in the soil

Bracts

Look like petals

Attract pollinators

Slide 18

Tendrils = Modified Leaves

Tendrils -- cling --> thigmotropism

Slide 19

Ice Plant Leaves Store Water: Succulent Plants: Desert Adaptation

Storage leaves

Slide 20