Plant Parts - StemsPlant Parts - StemsThe plant’s inner highwayThe plant’s inner highway

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Why do plants have stems?Why do plants have stems?

They have two functions:They have two functions: moving materials (water, minerals, food)moving materials (water, minerals, food) supporting the rest of the plantsupporting the rest of the plant

The stem has rings called “nodes”The stem has rings called “nodes” the space in-between is called the the space in-between is called the

“internode”“internode” At each of the nodes is a “bud”At each of the nodes is a “bud”

Stem Anatomy - ExternalStem Anatomy - External

Stem Anatomy - InternalStem Anatomy - Internal

When a plantlet develops from a seed, it may When a plantlet develops from a seed, it may have have oneone or or twotwo seed leaves or seed leaves or “cotyledons”“cotyledons” Plants with Plants with oneone are are “monocots”“monocots”

• Grasses - lawn grasses, corn, wheat, etc.Grasses - lawn grasses, corn, wheat, etc. Plants with Plants with twotwo are are “dicots”“dicots”

• Other plants - trees, beans, alfalfa, etc.Other plants - trees, beans, alfalfa, etc. Both types have different arrangements of Both types have different arrangements of

their their “vascualar bundles”“vascualar bundles”• These are the These are the veins and arteriesveins and arteries of the plant of the plant

Vascular BundlesVascular Bundles

Vascular BundlesVascular Bundles The arrangement of the bundles:The arrangement of the bundles:

Allows Allows dicotdicot stems to grow thicker & taller stems to grow thicker & taller• Trees have active, living tissue around the Trees have active, living tissue around the outsideoutside

of the trunk; inactive heartwood on the of the trunk; inactive heartwood on the insideinside. . • To make syrup, we tap the outside because it is To make syrup, we tap the outside because it is

busy moving sap (nutrients).busy moving sap (nutrients). Limits Limits monocotsmonocots to a certain size to a certain size

Inside the bundles:Inside the bundles: xylemxylem tissue moves materials tissue moves materials upup the plant the plant phloemphloem moves materials moves materials downdown the plant the plant

Plant Parts - RootsPlant Parts - Roots

Functions of the RootsFunctions of the Roots

Anchor the plantAnchor the plant Absorb water and Absorb water and

nutrientsnutrients

Different Types of RootsDifferent Types of Roots

Tap Roots – one main rootTap Roots – one main root Ex. CarrotsEx. Carrots Function – storage of excess foodFunction – storage of excess food

Fibrous Roots – branched rootsFibrous Roots – branched roots Spread out in the soil in search of water and Spread out in the soil in search of water and

nutrientsnutrients Root Hairs – tiny hair-like rootsRoot Hairs – tiny hair-like roots

Absorbs much of the water and nutrients for Absorbs much of the water and nutrients for the plant.the plant.

Parts of a seedParts of a seed

Embryo - develop into all the different Embryo - develop into all the different tissues that will ultimately make up the tissues that will ultimately make up the mature plant mature plant

Seed Coat - protects the internal parts of Seed Coat - protects the internal parts of the seed the seed

Endosperm - serves as a food source for Endosperm - serves as a food source for the developing embryothe developing embryo

Parts of the SeedParts of the Seed

endosperm

GerminationGermination

* When a seed sprouts and begins to grow

Monocot vs. DicotMonocot vs. Dicot

Dicot Germination Monocot Germination