Plant Lab
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Transcript of Plant Lab
Plants LabSpring 2013
Radish Root Hairs
Question
• Newly-formed cells soon will differentiate into different types of cells and form tissues. Plant regions having undifferentiated cells are known as meristems. We find meristematictissues at root tips.
• Where else in a plant should you expect to find meristems?
Leaves
Dermal Tissue
Plant Crystals: Raphides
Plant Crystals: Druses
Question• Crystals in different plants occur as raphides
(sharp needles), druses (star shaped) and other forms. Most are composed of calcium oxalate.
• How might a plant benefit from having needles or other crystals in its leaves?
Lower Epidermis
Question
• Another way plants protect themselves against excessive water loss is by secreting a waxy sort of substance to form a cuticle on the surface of a leaf. The cuticle is quite apparent in some leaf peels and cross sections
• In which types of habitats do you think you’re most likely to find plants with significant cuticles?
Ranunculus Cross section
Xylem and Phloem
Plasmolysis
• Elodea leaves again!!
• This time concentrate on chloroplast
• Work in partners– One scope has water the
other has salt water
– Use the wet slide mount technique
– Wait 15 minutes for salt water drawing • While we wait lets move to
photosynthesis and respiration
Photosynthesis and Respiration• Recall from Window into a cell
• Plants contain chloroplasts and mitochondria
• While the chloroplasts are active during the day they are creating sugars in the form of glucose
• When the mitochondria are active they use the glucose (sugar) to produce energy in the form of ATP
Question
• Most living things require oxygen.
– How can we breathe during the winter months in temperate zones? How do polar organisms manage?
• Some people enjoy plants in a closed/sealed container called a terrarium.
– How can the plants thrive with no access to the outside air?
Plasmolysis
Before adding salt After adding salt
Why does this Happen? Osmosis
• Osmosis example animation:– http://www.stolaf.edu/people/giannini/flashanim
at/transport/osmosis.swf
– In addition to the molecules and other structures, cells contain lots of water. Water is made of two hydrogen's and one oxygen molecule
– Molecules are in constant motion. Molecules that are crowded into one area (higher concentration) will Spread out into an area of lower concentration
Elodea Osmosis Explanation
• Plant cell in salt water:– Water molecules Leave the cell
to the environment because it has a lower concentration due to the salt
– Result = cell membrane lacks water pressure and it appears to shrivel up
• Plant cell in water:– Water molecules Enter the cell
because the environment has higher concentration of water
– Result = cell membrane is pushed outward by higher water pressure, giving the appearance to be spread out
Starch and Plastids
• Crackers
• in finger bowl
– What color are the following items when Iodine is applied (iodine reacts with starch it turns blue-black)
• Potato
• Been
• Cornstarch
• sugar
Starch and Plastids
• Plastids are cells that store specific things
– Chloroplasts is a plastid that stores chlorophyll
– Amyloplasts are specific plastid and it stores starch grains
Amyloplasts
Reminders
• Lecture:
– Lecture Exam #1 Tuesday
• Lab:
– Quiz 5 – Take home quiz