Plant Tissues and Organs Ch 35 and portions of Ch 36 & Ch 39 Tissues Part 22

True or False: The radicle is the first structure to emerge from a seed.

True

Where does water and mineral absorption primarily occur in roots?

Root hairs in the zone of maturation

Why can’t root hair cells directly control water movement?

Because water moves passively (osmosis), not by active control.

How do root hairs cause water to enter the plant?

They actively concentrate solutes (N, P, K), making the cell hypertonic, so water follows by osmosis.

What does “N” stand for in plant nutrients?

Nitrogen

In what forms is nitrogen absorbed by plants?

Nitrates and nitrite

Why are fungi important for nitrogen availability?

They help make nitrogen biologically available to plants.

What does “P” stand for?

Phosphorus (usually as phosphate)

What does “K” stand for?

Potassium (as potassium salts)

Why do plants need

so much H₂O (water)?

• Transpiration

• Cohesion/Tension “pulls” H₂O up to leaves  

• photosynthesis consumes H₂O splitting for energy and producing O₂ mitochondria in plant cells consume this

 

Plants use most of the water they absorb for metabolism. True or false

FALSE (they lose ~95% via transpiration)

Why is transpiration important beyond the plant itself?

It contributes to cloud formation and weather.

Both monocot and dicot roots have an endodermis around vascular tissues. True or False

True

How are vascular tissues arranged in monocot roots?

In a ring-like (radial) pattern inside the endodermis

How are vascular tissues arranged in dicot roots?

In an “X” or star shape at the center

In dicot roots, phloem is located between the arms of the xylem. True or False

True

What is the primary function of leaves?

Photosynthesis

What are the main tissues found in leaves?

Epidermis, mesophyll, vascular tissue, and sclerenchyma (structure)

What are guard cells?

Specialized epidermal cells that control stomata opening

What are stomata?

Openings that allow gas exchange

Why do plants need stomata?

Air flow CO₂ is a trace gas in “Air” plants need to move a lot of air to photosynthesize

Why must plants move large amounts of air?

Because CO₂ is present in very low concentrations in the atmosphere

What is mesophyll?

Photosynthetic group type tissue in the leaf containing many chloroplasts

Mesophyll is also called chlorenchyma in older literature. True or False

True

What are the two types of mesophyll?

Palisade and spongy

Function of palisade mesophyll?

Main site of photosynthesis (densely packed cells)

Function of spongy mesophyll?

Gas exchange (loosely arranged cells)

What do veins in leaves contain?

Xylem and phloem

Vascular tissues

xylem + phloem as “veins” that are defined by/protected by/given structure by sclerenchyma

Why is sclerenchyma associated with veins?

It provides structure and protection

What is the petiole?

is the leaf stem where veins coalesce

What is the blade?

The flat part of the leaf

What is a simple leaf?

One blade per petiole

What is a compound leaf?

Multiple leaflets per petiole

What type of venation do monocots have?

Parallel venation

What type of venation do dicots have?

Veins cross or Reticulate (net-like) venation

Monocot leaves have only spongy mesophyll. True or false

True

Dicot leaves have both palisade and spongy mesophyll. True or False

True

In monocots, stomata are found on both top and bottom leaf surfaces. True or False

True

In dicots, stomata are only on the bottom surface.

True

What are the two types of reticulate venation in dicots?

Pinnate and palmate