Plant Anatomy and Photosynthesis

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Questions and Answers

What primary function do stomata serve in a leaf?

Gas exchange and transpiration (correct)

Water storage

Nutrient absorption

Photosynthesis

Which layer of the leaf is primarily responsible for photosynthesis?

Lower epidermis

Palisade layer (correct)

Spongy layer

Upper epidermis

What is the primary function of roots in plants?

Produce flowers

Store sunlight

Conduct photosynthesis

Absorb nutrients and anchor the plant (correct)

What percentage of plant water is typically lost through transpiration?

90% Signup and view all the answers

What is the role of the endoderm in a plant's root structure?

Select minerals entering the vascular cylinder Signup and view all the answers

Which part of the root is directly responsible for increasing the absorption surface area?

Epidermis with root hairs Signup and view all the answers

What type of root system is characterized by a single, large root?

Taproot Signup and view all the answers

Which layer of the root covers its entire surface and is modified for absorption?

Epidermis Signup and view all the answers

What process is facilitated by the spongy layer of the leaf?

Gas exchange Signup and view all the answers

For which type of plant root system is soil erosion minimized?

Fibrous root Signup and view all the answers

What is the primary function of xylem in plants?

Transport of water and nutrients from soil Signup and view all the answers

Which characteristic distinguishes sclerenchyma cells from other plant cells?

They have thickened secondary cell walls Signup and view all the answers

What process describes the evaporation of water from leaves, which helps in water transport in plants?

Transpirational pull Signup and view all the answers

Which type of plant tissue is protective and covers the outer surface of the plant?

Dermal Tissue Signup and view all the answers

How do parenchyma cells support the plant when they are turgid?

By providing structural support and storing nutrients Signup and view all the answers

What defines long day plants?

They need more light than their critical photoperiod Signup and view all the answers

What role do guard cells play within dermal tissue?

They control the opening and closing of stomata Signup and view all the answers

Which plant hormone is primarily responsible for growth elongation and tropism?

Auxin Signup and view all the answers

What is the purpose of chromatography in botanical studies?

To identify plant pigments Signup and view all the answers

What does turgor pressure indicate in a plant cell?

Cell under water pressure Signup and view all the answers

Study Notes

The Leaf

The leaf is the site of photosynthesis in plants.
It is composed of an upper and lower epidermis, a mesophyll layer, and vascular tissue.
The upper and lower epidermis are covered by a waxy cuticle that prevents water loss.
Stomata, tiny openings in the epidermis, allow for gas exchange and transpiration.
Guard cells, containing chloroplasts, regulate the opening and closing of stomata.

Mesophyll

The mesophyll layer is divided into the palisade layer and the spongy layer.
The palisade layer, containing many chloroplasts, is responsible for photosynthesis.
The spongy layer, with large air spaces, facilitates gas exchange.

Roots

Roots anchor the plant, absorb nutrients from the soil, and store food.
The root structure consists of an epidermis, cortex, vascular cylinder, and endoderm.
The epidermis, with root hairs, increases the absorptive surface area.
The cortex contains parenchyma cells with plastids for starch storage.
The vascular cylinder, containing xylem and phloem, is surrounded by the pericycle, which gives rise to lateral roots.
The endoderm, with a Casparian strip, controls mineral entry into the vascular cylinder.

Nutrient and Water Absorption

The symplast, a continuous cytoplasmic network connected by plasmodesmata, allows for cell communication.
The apoplast, a network of cell walls and intercellular spaces, facilitates water movement within the plant.

Root Types

Taproot: A single, large root with lateral branches, common in dicots.
Aerial Root: Roots that grow above water in swampy or salt marsh environments, like mangroves, to aerate root cells.
Fibrous Root: Many thin roots, common in monocots like grasses, providing strong anchorage and minimizing soil erosion.

Stems

Stems support the plant, transport water and nutrients, and store food in some cases.

Plant Tissue Types

Dermal Tissue: The outermost protective layer of plants, typically composed of epidermal cells.
- Cuticle: A waxy layer protecting the leaf surface.
- Trichomes: Spike-like projections providing protection.
- Guard Cells: The only dermal cells with chloroplasts, regulating stomata.
Vascular Tissue: Responsible for transport.
- Xylem: Transports water and nutrients from roots to leaves.
  - Tracheids: Cells with thickened, lignified secondary cell walls for structural support and water transport.
  - Vessel Elements: Also thickened with lignin, contribute to water transport.
- Phloem: Transports sugars and other organic compounds throughout the plant.
  - Sieve Tube Elements: Lack a nucleus, forming chains for long-distance transport.
  - Companion Cells: Adjacent to sieve tube elements, providing metabolic support.
Ground Tissue: All other plant tissues besides vascular and dermal.
- Parenchyma Cells: Traditional plant cells, with some containing chloroplasts for photosynthesis.
- Collenchyma Cells: Have unevenly thickened primary walls, providing structural support.
- Sclerenchyma Cells: Very thick primary and secondary walls fortified with lignin, purely for support.

Additional Notes

Symbiotic organisms (Mutualism): An example is lichen, a combination of a fungus (absorbs water) and algae cells (photosynthesize).
Turgor Pressure: Pressure inside a cell caused by water or other factors.
Light Spectrum:
- Red light has the longest wavelength, while violet light has the shortest.
- Green plants reflect green light, which is why they appear green.
Photoperiodism: The flowering response of plants to the length of daylight. Plants are categorized as:
- Long-day plants: Require more light than their critical photoperiod to flower.
- Short-day plants: Require less light than their critical photoperiod to flower.
- Neutral-day plants: Flowering is independent of daylight length.
Auxin: A plant hormone involved in elongation and tropism.
Chromatography: A technique used to separate pigments.
Plasmodesmata: Narrow cytoplasmic threads connecting adjacent plant cells, facilitating communication.

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Description

This quiz covers the essential components of plant anatomy, focusing on leaves, mesophyll, and roots. Explore how these structures function in photosynthesis and nutrient absorption. Test your knowledge of the unique layers and processes that support plant life.