Posts Tagged ‘dicot’

Bio 11 – Exercise 7 – The Leaf

August 8, 2009

1.2 Give examples of monocot plants with netted venation

Taro

1.3 Give examples of dicot plants with parallel venation

Nerium oleander

2. Examine prepared slides of monocot, dicot and gymnosperm leaves.

Dicot:

Mesophyll (palisade, spongy) – present

Vascular tissue – enlarged vascular bundle in midrib; bundle cap

Midrib – present

Monocot:

Others – bulliform

Gymnosperm:

Epidermis – upper and lower indistinguishable

Stomata – sunken

Mesophyll – lobed mesophyll cells

Vascular tissue – presence of transfusion tissue

Blade – none

Others – resin duct

4. Examine several modified and specialized leaves and complete Table 7.3

Plant Specimen – Modification – Function

Onion – Bulb – Storage

Poinsettia – Bract – Attract agents of pollination

Pitcher plant – Insect trapping leaves – Nutrition

Peas – Tendril – Support stem

Notes:

Some answers differ for each class/group. You need to do the experiment.

For Table 7.1, specimens given might differ.

For Table 7.2, in some monocot specimens/slides the palisade and spongy might be indistinguishable.

Bio 11 – Exercise 6 – The Stem

August 8, 2009

1. Study a freshly cut stem of an herbaceous and woody dicot and a monocot plant

1.2 What stem has the most prominent node and internode? Why?

Dicot.

2. Study a vigorously growing coleus plant.

2. 1 Where do new leaves and internodes originate?

Nodes.

3. Study a longitudinal section of a coleus shoot apex under the LPO and observe the following: promeristem, leaf primordium, and primary meristems.

3.1 Tabulate the differences between a shoot tip and root tip.

Root tip has neither a leaf primordia nor axillary buds. Shoot tip has no root cap.

5. Follow the subsequent development of the stem tissues by examining cut sections from the uppermost to the lowermost internodes of coleus.

5.1 In which internode do you find differentiated tissues?

Lower internodes.

6. Study a prepared slide or free-hand section of a monocot stem.

6.2 How do primary tissues of this stem differ from those in coleus?

Monocot vascular bundles are scattered and the ground tissue isn’t partitioned into pith and cortex.

7. Focus on a single vascular bundle of a monocot stem under the LPO.

7.2 What is the pattern of xylem differentiation in the stem?

endarchy

7.3 Tabulate the anatomical differences between a monocot and dicot stem.

Monocot: scattered vascular bundles, no distinction between pith and cortex, no cambium, no secondary thickening.

Dicot: vascular bundles in a ring

8. Examine prepared slides of a woody dicot and pine stems. Study the different tissues under a compound microscope.

8.1 Which tissues constitute the bulk of the stem?

Secondary xylem

8.2 What tissues may have produced the additional cells? How do you account for this?

Vascular cambium. Secondary growth.

8.3 What protective tissue)s) is/are present in your specimen?

Periderm

8.4 What do you call the region with the loosely arranged parenchyma cells? What is its function?

Lenticel for gas diffusion.

8.5 Do you see companion cells and vessel elements in the pine stem?

Yes

8.6 Do you observe resin ducts and secretory cells in your specimens?

Yes

9. Examine cross, radial and tangential sections of a dicot and pine wood.

9.1 Differentiate the arrangement, shape and size of the wood rays in each section of the two specimens.

Cross section: Thin strands

Radial: Box-like

Tangetial: Pod-like

9.2 Tabulate the similarities and differences between a dicot and pine stem

Dicot: No resin canal

10. Examine various modified stems

Plant Specimen – Modification – Function

Water hyacinth – Enlarged – Buoyancy

Potato – Tuber – Storage and Vegetative reproduction

Ginger – Rhizome – Storage

Grass – Stolon – Vegetative reproduction

Cactus – Photosynthetic stem – Photosynthesis

Notes:

Some answers differ for each class/group. You need to do the experiment.

For Table 6.1: Only monocot has leaf sheath and no petiole, only woody dicot has lenticels.

For 7.1:

From subtlerainbows Multiply album.

From subtlerainbow's Multiply album.

Bio 11 – Exercise 5 – The Root

August 8, 2009

1.1 Classify the specimens according to their types of root systems:

corn (Zea mays L.) – fibrous

mung bean – tap

carrot (Daucus carota L.) – tap

radish (Raphanus sativus L.) – tap

sweet potato – tap

ginger (Zingiber officinale Roscoe) – fibrous

ginger lily (Hedychium coronarium Koen.) – fibrous

taro (Colocasia esculenta (L.) Schott.) or any Araceae – fibrous

onion or any Liliceae or Amaryllidaceae – fibrous

roots or leaves of life plant (Kalanchoe sp.) – fibrous

cuttings of begonia (Begonia sp.) – fibrous

bowstring hemp – fibrous

3. Examine the root system of water hyacinth and note the sequential development of tissues from the tip to the base.

3.1 Where are the youngest roots located? the oldest?

Youngest located at the tip of the root. Oldest located that the base of the root.

3.2 Identify the structure covering the root tip.

Root cap.

4. Examine under the microscope a cross-section of a young monocot root of spiderwort, Commelina benghalensis L. or corn and any dicot root. Locate and note the following primary tissues: epidermis, cortex, stele and pith.

4.1 Do you see the sub-epidermal cells (hypodermis or exodermis) in your specimen? If so, how many layers?

Yes

4.2 In which tissue are the intercellular spaces evident?

Sclerenchyma

4.3 What features make the endodermis morphologically distinct?

Casparian strip

4.4 Determing the number of layers and cell types in the pericycle

Single layer.

4.5 How many protoxylem poles do you see in your specimen?

4.6 Is the pattern of xylem differentiation endarch or exarch?

Exarch.

4.7 Is there a pith in the root core of your specimen?

Yes.

4.8 What tissue gives rise to the lateral root?

Pericycle

4.10 Differentiate a root hair from a branch root

Root hairs are unicellular, epidermal outgrowth which are only temporary. Branch roots are multicellular, endogenous, long lasting and develop from mature roots.

4.11 What region occupies the largest in the root?

Region of elongation

4.12 Tabulate the anatomical differences between monocot and dicot root.

Dicot – tetrarch, shows second growth, phloem between arms of xylem

Monocot – polyarch, vascular bundles arranged in a ring

5. Examine the cross section of a woody dicot root

5.1 Enumerate the cell components of the bark and wood

5.2 Do you find root hairs? Why?

No. Epidermis, where root hair is found, is sloughed off during secondary growth.

5.3 Which tissue usually functions in food storage in an old root? Young root?

Parenchyma

6. Examine the intact (entire) and cross-section of the root or radish, turnip, Pachyrrhizus erosus (L.) Urb. and sweet potato.

6.1 What tissues of these roots are edible?

Secondary tissue produced by cambia and upper part of root

7. Examine other specialized roots and tabulate their functions.

Plant Specimen – Specialized Part – Modification – Function(s)

Radish – Tap – Enlarged, fleshy – Food storage

Carrot – Tap – Enlarged, fleshy – Food storage

Sweet Potato – Tap – Enlarged, fleshy – Food storage

Turnip – Tap – Enlarged, fleshy – Food storage

Mangrove – Fibrous – Aerial root – Support

Pandan – Fibrous – Prop root – Support

8. Examine the cross section of the root of an aerial orchid and study the tissues

8.1 How does its morphology compare with the corn root?

Orchid has velamen which protects the aerial roots.

Notes:

Some answers differ for each class/group. You need to do the experiment.

For 4.1, 4.4 & 4.5, answers depend on your specimen/slide.


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