Lecture 7: Famine and Slavery; structures and functions of stems Flashcards
What type of division do lateral roots do, and from where?
from the percycle; perclinal division occurs; that is division that is parallel to the meristem
Where are all the tissues of stems derived from?
the shoot apical meristem
What does the shoot apical meristem look like?
- a dome or cone at top of plant
- region of rapidly dividing cells
true or false; stems do have zones?
false, they do not
Are the cells further from the peripheral zone more mature?
yes;
Where does the main cell division occur?
the peripheral zone
L1 how doe sit divide?
anticlinal manner
How does L2 divide?
either anti or periclinal
Where do leaves begin?
leaf buttresses
Where is vasculature formed?
from the procambium
- this differentiated as the lead matures
What are the 3 basic types of stem structure
once differentiated
- ) a continuous cylinder eg. magnolia
- ) a discontinuous cylinder (vascular bundles) eg. bean
- ) in bundles scattered throughout ground tissue (monocots) eg. maize
What has continuous cylinders?
magnolids, conifers, eudicots
What do monocots stem structure look like?
vascular bundles (scattered)
true or false; gas exchange can occur in stems
true
What are stems made up of?
Cortex (outer region)
Pith (inner region)
- contain parenchyma, usually with chloroplasts
- intercellular air spaces
-periphery often contains collenchyma
- may contain starch, crystals, glands, laticifers (latex exuding),
- sclereids may be present
What do laticifers produce?
- latex; an emulsion that hardens in air
What are the functions of stems (6)?
- ) production and elevation
- ) Long- distance transport
- ) storage
- ) perennating organs
- ) Dispersion
- ) symbiosis
Describe production and elevation
- applies to leaves, flowers and fruit
- for light capture
- advertising to insects and birds
Describe long distance transport
- long distance transport of water, minerals, photosynthates, nutrients, signals
What happens when a caterpillar wounds a plant( a type of plant?)
wounding sends signals to the plant via signal transduction pathway (as the saliva of the caterpillar stimulates it); the phloem will release volatile attractants to the atmosphere which will signal to a parasitoid wasp to lay their eggs in the caterpillar.
What does it mean by stem storage
- short term (annuals)
- long term (perennials)
What does it mean by perennating organs
- eg. rhizome, tubers, corms, bulbs
- are usually modified vegetative parts of the body (can survive for more than one year)
what does it mean by dispersion function
eg. water plants, stems break apart, carried by water currents
What does it mean by symbiosis
eg. cow wheat and ants
- seeds develop to resemble ants’ cocoons; carried to ants nest
- sweet liquid is released from the underside of the leaf; and ants feed
What are branches
- formed from outgrowth of axillary buds
- outgrowth of axillary buds are controlled by shoot apical meristem
- topping of the shoot releases bud from apical dominance
true or false; branches can form complex canopies
true
- short shoots
- long shoots
- vertical shoots
- horizontal shoots
What is sugar cane
- perennial grass
- thrives in moist, lowland tropics
- produces thick, stemmed canes
When did sugar can spread, and where to?
400-100 BC
- SE Asia, China, India
Why is sugar cane important?
- important source of sugar
- 1.2 Billion tonnes produced annually (Cuba, USA, Australia, India)
How much sucrose makes up the weight of sugarcane?
12- 15%
What is the correlation between slavery and sugarcane?
- it is the sugarcane cultivation that is responsible for slavery in the Americas
Who introduced sugarcane to Europe and when?
Columbus (1493)
Why is sugarcane favored?
it is an expensive commodity, favored as substitute for honey in Europe
What is the sugar can triangle?
- 17th century
- salt, cloths, firearms were traded for slaves in West Africa
- Slaves were sold to provide labour for the cane fields
- Britain- West Africa- West Indies- Britain
What was raw sugar/molasses shipped to England for?
to make processed sugar and rum
true or false; slaves died on the ships and the cane fields?
true
- populations had to be replenished constantly
How many slaves were shipped to work in the cane fields
10- 20 million
What made up the sugar cane triangle of the 18th century?
- West Africa - West Indies - Connecticut
When did the British impose the sugar tax on Americans and why?
1764
- they smuggled sugar into Connecticut
Who led the burning of the Gaspee
John Brown
True or false; the burning of the Gaspee pre-dated the Boston tea Part as action leading to American revolution
true
When did the Gaspee burn?
June 9 1772
What is the significance of the potato?
it is major staple food
Where was the potato first cultivated?
S. America 7000 years ago
When was the potato introduced to Europe?
16th century
Where is the potato mostly cultivated?
- cultivated throughout temperate regions and upland tropics
What was the significance of the potato to the Irish?
- Irelands’ soil and climate were ideal for growing potatoes
- could be hidden from British tax collectors
- staple diet until the 19th century
Why did the potato Blight come about?
due to monoculture
when was the potato blight?
1843
- phytophthora infestans
Within 5 years of the potato blight how many people have perished in Ireland?
5 million
How many people emigrated to the USA because of the potato blight?
1.5 million
How much % did the Irish population decline due to the potato blight of 1843?
30%
Which countries are now the major potato producers?
almost 1/3 of potatoes is harvested in China and India
