Plants 2c:Plant Parts

PPt. by, Robin D. Seamon

ROOTS & STEMS

ROOTS:

ROOTS:Activity

•Root Hunt Lab

•Grow a potato

•Grow seeds in a bag

•Carrot Top growing

•Root a cutting in water

ROOTS:

•hold the plant in the ground (anchor)

•Stop erosion

•Take in water & minerals for the plant

•Parts of a root:

Root cap: thin covering, protects root tip

Root hairs: threadlike parts of cells on surface of root

Phloem: path that food from leaves take down the plant to roots

Xylem: path that water & minerals take up the plant

Cortex: stores food in roots & stems

Taproot

Grows straight down with a few side branches

Fibrous Root

Grows more shallow, ‘hairy’; many fine- branching roots

foxtail

dandelion

Tuber: modified plant structure enlarged to hold nutrients

•stem tuber, (onion)

•root tuber, (sweet potato)

•potato tuber (potato)

•Bulbs: underground shoot that stores food; roots grow underneath (stem tuber)

Buttress Roots grow from the trunk for added support

Epiphyte: strangler

Fig

•Special kinds of ‘roots’: Link

Mangrove roots grow negative geotropism (up!) and then back down.

See LINK

In the Garden:

(Special roots & stems)

Carrots and BeetrootCarrots and beetroot are thickened tap roots which have very few lateral roots. Both are biennials i.e. they only grow for two years. In the first year they store food manufactured by their leaves in their tap root, and in the second year they use the stored food to produce flowers (called bolting). We harvest the carrots or beetroots before they bolt.   

GingerGinger is a rhizome - a type of stem which grows horizontally just under the surface of the ground. Leaves grow from buds at the nodes on the stem. The stem is thick and fleshy and stores reserve food for the plant.

  

PotatoesThis is likely to trick many people. Potatoes are not roots but underground storage stems which are formed when the growth point of an underground stem, a  rhizome, almost stops lengthening and increases greatly in thickness. This forms an underground storage organ which stores large quantities of starch.  

 

Sweet PotatoesSweet potatoes are the greatly thickened roots of the fibrous root system of the sweet potato plant which contain reserves of starch.  

  

Onions and GarlicOnions and garlic are bulbs. A bulb is an underground storage organ which consists of a very short stem on which fleshy bases of the leaves store food for the plant.    

STEM:

PPt. by, Robin D. Seamon

STEM:

Activity•Stem Hunt Lab

•Stem Rubbing

•Flower Chains

•Celery Dying

•Tropism experiments

•Woody stems & soft stems

•Carry water & minerals up and food down

•Hold the plant up (leaves & flowers)

•A tree’s stem is called a trunk

•Some grow underground (potato)

TROPISMS: movement of a plant

Positive tropism (moving toward the stimulus)

Negative tropism (moving away from the stimulus)

•Geotropism: all above ground plant parts grow away from gravity (up)

•Phototropism- all stems bend towards the sunlight-

•thigmotropism: response to physical contact- Vines: special kind of ‘climbing’ stem

•Some grow along the ground (runners) like strawberries ADVANCEVIDEO Creeper vines climb

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•Vine:

Runner

A special kind of stem that grows up and sideways; it climbs

A runner produces an identical plant to the mother

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PLANT LABS:1. Leaves: Identify & graph your collection into journal; view & draw fern spores;

Answer questions in Plant Journal.

2. Flowers: identify & draw 5 local spring flowers on white paper. Glue into journal.Roots: identify fibrous & taproots; draw 7 label root parts in journal; Answer questions in Plant Journal.

3. Seeds: seed dissection: label 3 parts of the seed into journal; observe pine nuts in pinecones-- sketch into journal; Answer questions in Plant Journal.

4. Stems: Compare three different types of bark. Notice the color & texture. How do the grains run? Is there a pattern? Create a bark rubbing with a dark crayon (rubbed sideways). Sketch the three specimens.

Header:

LAB: ROOTSRULES: BE GENTLE WITH THE ROOTS. They are wilting!

• What is the purpose of a root for a plant? ____________________, __________________________________

• What part of the root that carries water up the plant? _____________

• What part of the root carries water & nutrients down the plant? _____________

• Sketch & label the roots you have in your station into your journal. (root hairs, rootcap, fibrous root, taproot)

• What is the difference between a fibrous root and a taproot? _______________________________________________________________________________________________________

• Name some roots that we eat. _________________________________________________________________________

Header:

LAB: STEMRULES: BE GENTLE WITH THE BARK SPECIMENS.

• What is the purpose of a stem for a plant? ______________________________

• Compare three different types of bark. Notice the color & texture. How do the grains run? Is there a pattern? Sketch the three specimens.

• What is a vine?___________________________________

• What is a runner? __________________________________

Header: