33. Plant Anatomy

Roots and Shoots

Phenotypic Plasticity | Plant Growth and Development (Part 4) | Class 11

Plant Anatomy and Structure

Plant Anatomy and Morphology

Plant Structure

Root apical meristems are found 
(A) only in taproots. 
(B) only in lateral roots. 
(C) only in adventitious roots. 
(D) in all roots

Describe the general function of the shoot and the general function of the root system. Which tissues are continuous throughout these two systems? Suggest a hypothesis to explain why the shoot and root systems of different species are so variable in size and shape.

A strawberry plant mutant that fails to make stolons would suffer from 
(A) too little mineral absorption. 
(B) a tendency to topple over. 
(C) too little water absorption. 
(D) a reduction in asexual reproduction

 a multicellular extension of the root epidermis 

 No. Root hairs are extensions of individual cells. 

 an extension of the endodermis of roots 

 No. Lateral roots are outgrowths of the pericycle. 

 a modified root that provides support and anchorage 

 No. Root hairs are not modified roots but instead a part of the root that helps with absorption, not anchorage. 

 an extension of an individual cell that absorbs water from soil 

Consider where root hairs are found.

A root hair is __________.

Plants: Developmental plasticity in plants, and Stems

Animation: Leaf Anatomy

Environmental Effects on Phenotype

 No. Tissues are at a lower level of organization. 

 No. Plants have dermal, vascular, and ground tissue systems. 

 None of the listed responses is correct. 

 No. One of the other choices is correct. 

Consider the place of leaves and stems in this hierarchy.

In the hierarchy of biological organization, what is the shoot?

Phenotypic Plasticity

Roots of Plants | Morphology of Flowering Plants | Plant Morphology | Don't Memorise

 No. The spines are modified leaves found along the paddles, which are modified stems. 

Consider where leaves attach to the plant.

The shoot system of a prickly pear cactus consists of broad paddle-like structures covered with clusters of spines. The spines are modified leaves, so the flat green paddles must be modified versions of what structure?

Environmental Effects on Phenotype | AP Biology 5.5

Animation:  Stem Cross Sections

The root pericycle is the site where 
(A) secondary growth originates. 
(B) root hairs originate. 
(C) lateral roots originate. 
(D) the endodermis originates

 No. The cortex is located between the stele and the epidermis. 

 No. The phloem is close, but the xylem is more centrally located. 

 No. The stele of roots is a centrally located cylinder. In monocots, pith forms the central core of the stele, but in eudicots, the vascular tissue, specifically the xylem, is in the center of the root. 

 No. The epidermis is the outermost tissue layer. 

How is vascular tissue arranged in eudicot roots?

Which of the following is closest to the center of a buttercup (eudicot) root?

 Additional organic material in a plant's cytoplasm 

 No. This does account for some cell expansion, but not 90%. 

 No. The question refers specifically to expansion at the cellular level. 

 Additional organic material stored in vacuoles 

 No. Additional organic material is not stored in the vacuoles. 

 No. Plants store most of the water taken up during cell expansion in a large central vacuole. 

 The uptake of water that is stored in a large central vacuole 

Consider the differences between animal and plant cell expansion.

What accounts for about 90% of a plant cell's expansion?

Plant Cells Review

 No. Opposite phyllotaxy appears to be advantageous in areas of high sunlight, where some shading of lower leaves is helpful. 

 Spiral (or alternate) phyllotaxy with an angle of 97.5 degrees between each leaf 

 No. Spiral phyllotaxy is correct, but the angle is incorrect. 

 No. Spiral phyllotaxy with a particular angle is most advantageous. 

 Spiral (or alternate) phyllotaxy with an angle of 167.5 degrees between each leaf 

 Spiral (or alternate) phyllotaxy with an angle of 137.5 degrees between each leaf 

This particular feature has evolved very precisely.

What type of phyllotaxy minimizes shading of lower leaves?

Genotype Expression

 Palisade mesophyll, spongy mesophyll, lower epidermis, upper epidermis, vascular bundle 

 Vascular bundle, lower epidermis, upper epidermis, spongy mesophyll, palisade mesophyll 

Review the anatomy of a leaf.

Which of the following is the correct arrangement of structures from the inside to the outside of a leaf blade?

 No. Only roots have a central cylinder of vascular tissue inside a cortex. 

 No. Meristems are undifferentiated tissues that divide to form new cells. 

 No. In stems there are several vascular bundles. 

 No. A section through a terminal bud would reveal meristematic tissues. 

Consider the arrangement of vascular tissues in various plant parts.

A cross section of a plant part exposes epidermis, a thick cortex, and a central cylinder of xylem and phloem. This part is a __________.

Animation: Leaf Abscission

Shoots and Leaves

 No. The internode is the space on stems between nodes. 

 No. The petiole is the structure that joins the leaf to the stem at the node. 

 No. The shoot apex contains developing leaves and a compact series of nodes. 

Review the structures of stems and leaves.

Leaves occur at intervals along the plant stem. What is the region where a leaf is attached to the stem?

Vascular Plants = Winning! - Crash Course Biology #37

 No. With the exception of guard cells, cells of the epidermis do not contain chloroplasts. 

 No. Pith is a feature of stems, not of leaves. 

In most leaves, chloroplast-containing cells are most closely compacted in the __________.

Root System

 No. Leaves consist of blades, and in compound leaves the blades consist of leaflets. 

Review leaf anatomy.

Leaves consist of __________.

Shoot system

Travel Deep Inside a Leaf - Annotated Version | California Academy of Sciences

 No. In most plants, roots are underground and have no need for chloroplasts because there is no light for photosynthesis. 

 Only the shoot epidermis gives rise to vascular tissues. 

 No. Dermal and vascular tissues are two different tissue systems, neither root epidermis nor shoot epidermis. 

 Only the shoot epidermis is replaced by periderm in woody plants. 

 No. Older regions of both the shoot epidermis and root epidermis are replaced by periderm. 

 Only the root epidermis contains guard cells. 

 No. Guard cells are found in the leaf epidermis. 

 Only the shoot epidermis produces a waxy cuticle. 

Consider the location and functions of each.

What is the difference between the root epidermis and the shoot epidermis?

What does the cuticle do? What do stomata do? Predict how the thickness of the cuticle and the number of stomata differ in plants from wet habitats versus dry habitats.

Internal Structure of Roots

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