Botany: Stems

What is the name for A?

Terminal Bud

Located on A, what are these leaves called?

Bud Scales

What is the name for B? Note: imagine there is a leaf.

Axillary Bud

What is the name for C?

Node

What is the name for D?

Internode

Give three locations where you can find the apical meristem.

Tips of shoots, tips of roots, and axillary buds

What is the arrangement of leaves called?

Phyllotaxy

What is one leaf per node called?

Alternate

What is two leaves per node called?

Opposite

What is three or more leaves per node called?

Whorled

What is it called when there are two rows of nodes?

Distichous

What is it called when there are 4 rows of nodes?

Decussate

What are the 3 names of the node arrangements?

Distichous

Decussate

Spiral

Name 5 of the Special Stems

Stolen/runners

Bulb

Corm

Rhizome

Tuber

What is a stolen/runner?

They have long and thin internodes with minimal leaves and found above ground.

What is a bulb?

Has short roots with thick fleshy leaves.

What is a corm?

Has a thick stem with papery leaves

What is a rhizome?

Has fleshy horizontal stems that spread underground

What is a tuber?

has underground storage (think of potatoes)

In a stem, what is the epidermis made out of?

Parenchyma Cells

What is cutin? What does it do?

Cutin is a fatty substance that can build up to make a cuticle that is covered in wax.

A stem has cutin, but because it needs to breathe, what does it have?

It has guard cells

What do guard cells do?

A guard cell lets CO2 in but because it is open, it’ll also let water vapor and oxygen out.

What is a cuticle for?

It prevents against water loss and bacteria and fungi from getting in.

What is a trichome?

A trichome is an elongated epidermal cell that is also called plant cells

What does a trichome do?

A trichome decreases water loss, reflects excessive light, slows down air flow outside of the plant, and helps deter against herbivores (mechanical or chemical)

Where is the cortex?

Underneath epidermis

What is in vascular tissue?

Xylem and Phloem

What does a xylem do?

Xylem moves water up the plant

What does a phloem do?

Phloem moves sugar solution down the plant

What is a xylem?

They are dead hollow cells that makes water move up the plant using conduction by hydrogen bonds.

What is in a xylem?

There are tracheary elements that have tracheids and vessel elements

What are tracheary elements?

They are in the xylem and consist of tracheids and vessel elements.

What are tracheids?

are in the xylem and have pits that slow movement

What are vessel elements?

they are in the xylem and they are complete holes/ perforations that decrease friction

What are the cells in the xylem?

Dead at maturity sclerenchyma cells

What cell walls do xylem have?

Both Primary and secondary

What is the phloem?

Parenchyma tissue with only a primary cell wall that are alive

What are sieve elements?

They are sieve cells and sieve tube members

What are sieve cells?

Sieve cells have an elongated spindle shape

What are sieve tube members?

Sieve tube members are short, fat and stacked

What is the difference between the stems of monocots and herbaceous dicots?

Monocot stems have their vascular bundles scattered randomly and in the dicots they are in a ring.

In the dicots their ground tissue is separated by the ring of vascular tissue into an outer cortex and central pith.

What is found at the center of a eudicot stem?

The pith.