Too much lettuce…

• Someone’s group planted way too many lettuce seeds in their seedling trays.

• We’ll be taking some and making little self-watering planters (look to the right)

Self-Watering PlanterSupplies:

• Recycled Plastic Bottle• Lettuce Seedling (1 week old)• String (to act as a wick)• Worm Castings• Regular Soil• Fertilizer• Tape

Building Instructions:

• Remove the plastic label, and clean the inside and outside of the bottle.

• Cut the bottle in half at the 2nd ‘ring’ from the bottom.

• Puncture a hole through the lid of the bottle• Pull the wick through the hole.• Add some gravel to the bottom, then dirt on

top, and you’re done!

M5 Lesson – Plant growth, Flowers / Fruit, and Tropisms.

What is a tropism?

Root hairs

maturation / differentiation

elongation

division

Root cap

Review (Exit Slip Question)

• EXIT SLIPS: WRITE YOUR ANSWER IN COMPLETE SENTENCES ON THE EXIT SLIP PAPER. NO TALKING, COPYING, CHEATING.

• What is the importance of the root cap for the growth of roots through the soil?

Functions of the Root Cap

• 1) Protects the delicate meristem tissue.• 2) Secretes lubricants (called mucilage) to help the

root move through the soil more easily.• 3) The root cap produces hormones that guide the

root downwards. Growth in response to gravity is called gravitropism.– If the root cap is removed, sometimes the root will grow

in random directions.• Water / nutrients AREN’T absorbed by the root cap!

1) Fill in the Blank Notes: Root Growth Zones, Tropisms, and Flowers!

• The zone of division, just above the root cap, has meristem tissue; this is where new root cells are produced.

• These cells become specialized later (as part of the vascular chamber, root hairs, part of the Casparian strip, or replacing damaged cells on the root cap.)

• Water / minerals aren’t absorbed here either!

2) Further Notes: Growth Zones

• The zone of elongation is where cells produced in the zone of division start to grow and elongate. This growth pushes the root downwards through the soil.

• Water / minerals aren’t absorbed here either – it’s still a growth zone!

3) Zone of Differentiation / Maturation

• This is where cells from the zone of elongation become specialized.

• They will form the vascular cylinder, casparian strip, and other water-absorbing and transporting cells.

• The root hairs are structures in the ZoM that absorb water and minerals into the root of the plant!

4) Water movement through the plant!!

• Water loss through the leaves is known as ________________________, and is said to be the main driving force of water movement through the plant. As water evaporates out through the _________________ of the leaves, cohesive forces (water’s attraction to itself) bring water in through the root hairs!

transpiration

stomata

5) Growth in response to the environment

• The roots, to gain access to water, will grow in response to gravity; this is known as _____________________________ (Figure 1a). The shoot of the plant will sometimes grow against gravity, (negative gravitropism), and the root will usually grow towards the pull of gravity to dig deeper into the soil.

gravitropism

6) Growth in response to touch• When a plant grows in response to

touch, like those in Figure 1b, it is known as: ______________________________.

• What is the purpose of a plant growing in response to touch? What type of plants would utilize this type of growth the most? ______________________________

thigmotropism

Vines, creepers and other climbing plants.

Thigmonasty: the Sensitive Mimosa• As a defense

mechanism, the plant leaves of Mimosa pudia, a.k.a. “sensitive mimosa,” swell shut, to look ‘dead’ or unappetizing to predators.

ii) The Venus Fly Trap

• The ‘trap’ is a modified leaf.• Special hairs on the inside

act as a trigger; when more than one is touched, the trap snaps shut!

• It uses water pressure to increase the size of cells along the outer edges of the leaf, and the trap closes!

Other tropisms…

Growth in response to light is known as _______________________. A plant growth hormone produced near the meristem in the growth regions of a plant called ____________________ makes this happen, as shown in Figure 2. It is released or produced in response to light, and moves to the shaded side of the shoot; this can help the plant face towards a light source by growing in that direction!

phototropism

auxin

Growth in response to light:Auxin

Exit Slip Question

NO TALKING, NO COPYING. BOOKS AWAY!!• 1a) What’s the difference between

thigmotropism and phototropism? Give an example of each. (2 marks)

• 1b) How could these two tropisms work together to help a plant, like a vine, survive in a dense /shaded forest. (1 mark, 1 bonus mark)

Flower Diagrams – Observation and dissection