FRST 303 Space

What is a tree?

A woody plant that is perennial (lives multiple years) with a single stem and lateral branches, reaching at least 8 m and largest 116 m

How is the scientific name of a tree written?

Genus name then species name in italics or underlined

What is the name of this Tree Of The Day?

Western redcedar (thuja plicata) [Despite the name, it’s actually a cypress cause of its “needle” leaves]

What makes the Western redcedar unique?

It has the widest diameter of any tree species in BC and is resistant to terpenes (naturally occuring compounds)

How are Western redcedars used by BC First Nations?

To make canoes, hats, baskets, and for carving totem poles

What are four ways that forests are important to humans?

1. Carbon uptake reduces greenhouse gases in the atmopshere

2. Produce oxygen for us to breathe

3. Wood is a sustainable building material

4. Forest bathing improves human mental and physical health

Why are forests important for biodiversity?

Provide them habitat

What is the name of this Tree Of The Day?

Ginko (Ginko biloba)

What makes the Ginko unique?

It is the only living species in its phylum and its seeds have medicinal properties

Early bacteria (prokaryotes) used chemical energy, so what was the first photosynthetic organism?

Cyanobacteria (“blue-green algae”) were the first photosynthetic organism around 3.5 billion years ago (SHEESH)

Why is the term “blue-green algae” not quite correct?

Algae are plants, which are eukaryotes while cyanobacteria are prokaryotes

What evidence do we have for cyanobacteria?

Fossilized stromatolites formed by cyanobacteria

What is the endosymbiotic theory for chloroplasts about?

The chloroplast evolved from being a cyanobactereum that was engulfed by a single-celled prokaryote and became an organelle inside the cell

What were the first plants?

Single-celled algae living in aquatic environments

Which kingdom of eukaryotes was last to evolve?

The best one kingdom Plantae

Where was the first place evolving plants inhabited before moving on land?

Intertidal zones (sometimes wet and sometimes dry) and estuaries

How is temperature different in aquatic environments versus on land?

Narrow temperature variability in water versus extreme high and low temperatures possible on land

How are nutrients different in aquatic environments versus on land?

Nutrients/CO2 are accessible (in the photic zone) in water versus CO2 is in the atmosphere and nutrients buried in the soil on land

How is light different in aquatic environments versus on land?

Not too harsh light exposure and decreases with depth in water versus harsh light and UV exposure on land

How is weight different in aquatic environments versus on land?

Plants are supported by water versus both gravity and wind can bring a tree down on land

What are the four important features of a plant cell?

1. Cell wall made of cellulose that provides structural support and rigidity

2. Chloroplast for photosynthesis

3. Other plastids for pigment and starch storage

4. Vacuole for containing water, sugars, and salts to provide turgor pressure for the plant

What were the early terrestrial plants?

Mosses and liverworts which were small, non-vascular plants that could not actively transport water and nutrients

What was the first major step in plant evolution?

Vascular tissue: xylem transports water up and phloem transports nutrients up and down

What is the difference between a moss and a club moss other than size?

Mosses are non-vascular while club mosses are vascular

What was the second major step in plant evolution?

Larger leaves = more SA to absorb sunlight = more photosynthetic potential

What was the third major step in plant evolution?

Gymnosperms and angiosperms reproducing through seeds

What are four advantages seeds have over spores?

1. Protection by seed coating

2. Can be transported via animals eating them

3. Have nutrients to help plant embryo grow

4. We eat seeds (rice, corn, and beans)

What is an advantage spores have over seeds?

They are much cheaper to produce than seeds

What was the final major step in plant evolution?

Flowering plants with fruits and flowers

From Quiz 1, apparently this is important

This too; does NOT increase ozone levels

What Tree of the Day is this?

Monkey puzzle or pehuen (Araucaria araucana)

Why is the tree important to the Pehuenche people in Chile?

The seeds are a staple part of their diet and they considered it sacred

True of False: All gymnosperms (naked seeds without fruits) are conifers

False. All conifers are gymnosperms, but not all gymnosperms are conifers

True or False: Most conifers, but not all, are evergreens (have leaves on throughout the seasons)

True

True or False: Not all evergreens are conifers

True. There are evergreen angiosperms

True or False: All conifers have cones

False. Most, but not all, conifers have cones

What are the 2/4 phylum of gymnosperms that we are expected to know?

Ginkophyta (1 species remember) and Coniferophyta (600 conifer species)

What is the seed structure of conifers (5 things)?

1. Embryo (2N)

2. Megagametophyte (N): Provides nutrients for the seed to germinate and us if we decide to eat the seed

3. Nucellar cap

4. Cotyledon

5. Seed coat

Where are seeds cones and pollen cones located relative to each other?

On the same tree, with the pollen cones lower on the tree for the wind to carry pollen up to the seed cones

True or False: This is a pine cone

False. A pine cone can only come from a pine tree

Most conifers have “wings” for wind dispersal; what is an advantage of this?

The tree does not have to spend resources on attracting animals

As we know most, but not all, conifers have cones, how are Yew tree seeds dispersed?

By birds, not the wind

Why is it better to call pine nuts “pine seeds”?

Nuts are a type of fruit and only angiosperms produce fruits; pines are gymnosperms

True or False: 99% of all tree species are angiosperms

True

What is the structure of an angiosperm seed (4 things)?

1. Embryo (2N)

2. Endosperm (3N): Provides nutrients for the seed to germinate

3. Cotyledon

4. Seed coat

What are monocots and dicots?

Monocots have one cotyledon and dicots have two cotyledons

Examples of monocots?

Rice, wheat, and palm trees (which are not actually trees because they don’t have a woody stem)

Examples of dicot?

All angiosperm trees are dictos where they store resources in their two cotyledons

Where are nutrients found in an angiosperm seed?

In both the endosperm and cotyledons

What is the #1 method to disperse angiosperm seeds?

Animal transport because it can usually go farther

What are the other methods?

Light hairy seeds blown by the wind, hooks to attach to things, and transport by water

What is seed dormancy?

It is when a seed is dispersed and mature yet does not grow despite favourable conditions

What about embryo dormancy (a type of seed dormancy)?

Requires exposure to low T to get out of dormancy and then heat and moisture to germinate

What is the purpose of embryo dormancy?

So the seed doesn’t grow during winter and die; rather it grows during spring to summer time

What is seed coat dormancy (another type of seed dormancy)?

When a seed coating’s impermeability to water and gasses cause it to remain dormant that can only be broken by physical damge or low T

What is the purpose of seed coat dormancy?

Same as for embryo dormancy

C

Why have trees evolved to grow tall

Better access to sunlight (competition)

What tree of the day is this and what makes it special?

Coast redwood (Sequoia sempervirens) and it is the tallest tree species in the world

Why is Coast redwood (Sequoia sempervirens) used for fences, decks, and outdoor furniture?

Because it is decay resistant

What tree species do these seeds and cones belong to?

Of course, coast redwood

What are stem cells and what are they called in plants?

Undifferentiated cells that can continue to divide for hundreds or thousands of years that are called meristematic cells in plants

Where are the two types of meristematic cells?

Shoot apical meristems at the stem and branches and root apical meristems

True or False: The root apical meristems are at the root tips just comme how the shoot apical meristems are at the tip of stems and branches

False. While the shoot apical meristems are at the tip of stems and branches, the root apical meristems are not at the root tips so as to not get torn by the soil

So, what is at the root tip?

Slimy cells called mucilaginous cells

What grows first?

The roots

What does mutualistic mycorrhizal relationships involve?

Plant roots access more water and nutrients due to the fungi while the fungi receives food from the plant (Win-Win)

What other type of mutualistic relationship can roots have?

With bacteria that fix nitrogen from the atmosphere into its available nutrient forms in exchange the bacteria receives sugars

What does it mean that roots are gravitropic and shoots are anti-gravitropic?

Roots grow down and shoots grow up

What four resources do roots need to grow?

1. Water

2. Nutrients in the soil

3. Nitrogen

4. Space to anchor

True or False: Roots grow in a set pattern

False. They grow where resources are available

What is the name of this stem?

The main stem aka the leader stem and is where the shoot apical meristem is at the tip

True or False: There are other shoot apical meristems at the tip of every branch

True

In what interval do shoot apical meristems produce new leaves?

At a fixed pattern arrangement (phyllotaxy) for best sunlight access

What is the phyllotaxy of this plant?

1,3

How do lateral branches form?

When a new shoot apical meristem forms in the axil of a leaf (where a leaf joins the stem aka the V shape)

What is the phyllotaxy of this Hazelnut tree?

1,2

Name the arrangement patterns from left to right

Alternate, Opposite, and Whorled

This plant produces leaves in opposite pairs: Which is the younger pair and which is the older pair

(This shows the shoot apical meristems and developing leaves of coast redwood) Which is the youngest pair?

The ones closer to the centre aka the shoot apical meristem

True or False: Trees can get taller by dividing at the branches and at the top

False. Trees can only get taller by dividing at the top from the shoot apical meristem tip of the leader

True or False: Branches move up in height as the tree grows taller

False

What is this Tree of the Day?

Giant sequoia (Sequoiadendron giganteum)

What makes it unique?

Tallest tree species by main stem

What is similar between Giant sequioa, Coast redwood, and Western redcedar?

They are all in the cypress family

What do Herbaceous (non-woody plants) only have?

Primary vascular tissue: xylem and phloem

Why is secondary vascular tissue important for trees to grow tall?

For support and water conduction/transport

What is the vascular cambium?

A circle of meristem that produces secondary growth in width by dividing to form the secondary xyelm (wood) to its inside and secondary phloem (inner bark) to its outside

What is wood?

Cells with thick and strong secondary cell walls

True or False: Most wood cells die immediately after they mature

True; due to apoptosis

What are wood cells called in conifers and what do they do?

Tracheids that are involved in water transport and support (think hollow straws)

What do wood cells do in angiosperms?

They are more specialized for water transport and support

What does wood formed in the spring/earlier in the year do for non-tropical trees?

Water conduction/transport up

What does wood formed in the summer/later in the year do for non-tropical trees?

Support

What are four useful properties of wood for us?

1. Sustainable building supply

2. Paper

3. Fire/heating

4. Cellulose as a bulking agent in food

How do tree rings look in the growing season (spring)?

Thinner due to the wood cell walls being less dense at the time and a large lumen (opening) for water conduction/transport

How do tree rings look in the summer?

Thicker due to the wood cells walls being denser for support

What do Earlywood tracheid and Latewood tracheids do?

Earlywood tracheid (spring) conduct water and Latewood tracheid (summer) support [Pattern]