1. Nicotiana tabacum Falak Bhatt IB 423 May 4, 2005

2. Classification Division Magnoliophyta Class: Magnoliopsida
Order: Solanales
Family: Solanaceae
Genus: Nicotiana
Dicot

3. History Indigenous to North and South America
1 BCE: Experts believe American inhabitants have begun finding ways to use tobacco, including smoking and chewing
Native Americans smoked before Europeans arrived in America, gave dried leaved as gift to Columbus
Settlers brought habit back to Europe
U.S. early colonies made most of internal revenue from tax of tobacco export
Say about different ways smoking was done…fires tobacco leaves dried, smoked with other leaves

4. Root Hair (w/ trichoblast)
Dicot-Open Root System, Fibrous
Root Hair (w/ trichoblast)
Rhizodermis
Apical Meristem
Restate difficulty of exact locations b/c of whole mount and small size of roots. Mention where vascular cylinder is…look at pg 3 of lab 11. Say where zones are pg 3 lab 11. mention total root length varied from widely with longest reaching 25inches.
Root Cap
Columella
Root tip 10x-TOL B

5. Root Tetrarch development Phloem Xylem Pericycle
Root stele has tetrarch development. Exarch young cells on inner part-centripetal. lab 11. endodermis ripped off
Pericycle
Root xs 20x Phloro.

6. Root: Secondary Growth
Ray
Secondary Xylem
Root xs 10x TOL B
Primary Xylem
Root xs 4x TOL B

7. Root
Vascular Tissue
Trichome
Whole root 10x TOL B

8. Continuous vascular tissue
Stem
Bicollateral phloem
Continuous vascular tissue
Crang and Vassilyev
Cortex- Parenchyma
External Phloem
Vascular Cambium
Xylem
Internal Phloem
cambium produces a continuous cylinder of secondary vascular tissues. Note the strands of internal phloem around the periphery of the pith marking the location of vascular bundles prior to stem secondary thickening. The internal phloem is preserved in its primary state because no vascular cambium is produced between it and the internal portion of primary xylem. Although internal phloem may be found in economically important plants, it is not the typical vascular pattern among angiosperms. Tobacco stem: Continuous vascular cylinder is derived from cambium
No isolated vascular bundles
No secondary growth of internal phloem
Pith
Stem xs 10x

9. Multicellular, uniseriate trichomes
Stem
Multicellular, uniseriate trichomes
Trichomes
Stem xs 20x
Name all the parts again…pith, parenchyma phloem. But Point out the trichomes and epidermis. Trichomes cover all of plant
Epidermis
Stem xs 10x

10. Next up…Leaves Bifacial Reticulate (netted) venation-Dicot Trichomes
Reticulate (netted) venation-Dicot
Trichomes
Trichomes cover leaves and all surfaces. Palisade has cholorplasts…unstained leaf looks green like above. Bifacial is also called dorsiventral
Palisade Mesophyll
Spongy Mesophyll
Leaf xs 10x

11. Leaves Abaxial Adaxial Amphistomatic Simple
Leaf peel 20x
Leaf peel 20x
Simple- single blade w/ petiole (stalk and major vein). Point out how there is no pattern in stomata, that’s why it is anomocytic. Some perpendicular surrounding cells, some parallel, sometimes 3, sometimes 4 surrounders.
Abaxial
Adaxial
Amphistomatic
Simple
Anomocytic stomatal arrangement

12. Major Leaf Vein…Bicollateral view
Leaves
Major Leaf Vein…Bicollateral view
Phloem
Vascular Cambium
Xylem
Phloem

13. Leaves: Gap and Trace Outer endodermis Inner endodermis Stem xs 10x
Mention trichomes still visible. Pith, outer and inner endodermis.
Stem xs 10x
Leaf trace
Leaf gap

14. Reproductive Structures
Optional Features
Reproductive Structures
Ovules
Locules
Ovary longitudnal
Ovary Wall
Sepal
Ovule Locule
Bud xs

15. Reproductive Structures
Endosperm
Testa
Integument will become seed coat. embryo is surrounded by three to five layers of rather thick-walled endosperm cells in the mature seed. The periphery of the endosperm is pressed against the thin seed coat (testa), consisting of cutinized and lignified dead cells
The embryo is surrounded by three to five layers of rather thick-walled endosperm cells in the mature seed. The periphery of the endosperm is pressed against the thin seed coat (testa), consisting of cutinized and lignified dead cells
Bud xs 10x

16. Reproductive Structures
EMBRYO
Cotyledons
Radicle
Endosperm
Testa (seed coat)

17. Secretory Structures & Nicotine
Tobacco leaves have 2 types of Trichomes
Short stalked
Nicotine
Organic alkaloid and powerful neurotoxin
Biosynthesis in roots, accumulate in leaves
Long stalked
Diterpeniods
Talk about new potent tobacco plants that can produce more nicotine by shutting diterpenoid secretion to allow for more nicotine biosynthesis.
Glover 2000

18. References Crang, R & Vassilyev A. Plant Anatomy CD. 2003.
Glover, Beverley J. Differentiation in plant epidermal cells.
Journal of Experimental Botany. Vol. 51, No. 344, pg , March 2000.