Pharmacognosy II Week 9 Quiz
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Questions and Answers

The root of a plant develops leaves.

False (B)

The root-cap or calyptra is a specialized tissue that covers the growing point of the root.

True (A)

What type of root system is present in grass?

Fibrous root system

What type of root system is present in a carrot?

<p>Tap root system</p> Signup and view all the answers

Which of the following is NOT a type of root?

<p>Flowering root (C)</p> Signup and view all the answers

Match the following types of roots with their characteristics:

<p>Primary root = Develops vertically downwards and is the main root of the plant. Secondary root = Arises from the primary root. Adventitious root = Develops from the stem or other plant parts. Prop root = Provides support and stability to tall plants. Aerial root = Develops in the air and may be involved in anchoring or absorbing moisture.</p> Signup and view all the answers

What are the three main stages of root development, based on their age?

<p>Young root, intermediate, and old root.</p> Signup and view all the answers

What is the primary function of the root-cap?

<p>Protecting the growing point of the root (D)</p> Signup and view all the answers

Which of the following is a characteristic of the subterranean stems?

<p>They are fundamentally a mean of propagation and storage. (B)</p> Signup and view all the answers

Which of the following is NOT a type of subterranean stem?

<p>Leaf tuber (A)</p> Signup and view all the answers

What are the three main ways in which subterranean stems can grow?

<p>Horizontally, Vertically, Obliquely</p> Signup and view all the answers

Which of the following is a type of bulb?

<p>Both A and B (C)</p> Signup and view all the answers

What is the basic difference between a stem tuber and a root tuber?

<p>Stem tubers develop from swollen underground stems, while root tubers develop from swollen roots.</p> Signup and view all the answers

A corm is an erect, underground stem that is typically covered by brown scales, usually found at the base of the stem itself.

<p>True (A)</p> Signup and view all the answers

The presence of radial vascular bundles and pith is a characteristic that helps distinguish a subterranean stem from a root.

<p>True (A)</p> Signup and view all the answers

Which of the following is NOT a way to describe the condition of a subterranean stem for identification?

<p>Color of the external layer (D)</p> Signup and view all the answers

The presence of a root-cap or calyptra is characteristic of both subterranean stems and roots.

<p>False (B)</p> Signup and view all the answers

The vascular bundles in subterranean stems can be either open or closed.

<p>True (A)</p> Signup and view all the answers

The presence of scale leaves is only found in underground stems.

<p>False (B)</p> Signup and view all the answers

Adventitious roots are always found on the main root.

<p>False (B)</p> Signup and view all the answers

What are the two main categories of subterranean stems based on their position?

<p>Root stock and Stem tuber</p> Signup and view all the answers

What are the main differences between roots and subterranean stems from a morphological perspective?

<p>While both serve storage functions, roots are typically devoid of scale leaves and axillary buds, lack the growing point protected by root-cap, and have different arrangements of vascular bundles and pith.</p> Signup and view all the answers

Explain the difference between "root stock" and "stem tuber" as types of subterranean stems.

<p>Root stock, sometimes referred to as a 'root-stock', is a type of underground stem that serves as the base for a plant's growth, sometimes referred to as the base of the stem itself. A stem tuber is a swollen underground shoot of a stem that is formed for storage during propagation and is separate from the base of the plant.</p> Signup and view all the answers

The type of root system plays a role in the plant's ability to absorb water and nutrients.

<p>True (A)</p> Signup and view all the answers

What is the meaning of the term “endogenous” as applied to root branching?

<p>In the case of root branching, endogenous refers to the origin of the new branches forming within the tissues of the main root, inside the root structure.</p> Signup and view all the answers

What does the term ‘Sobole’ refer to?

<p>Sobole refers to a specific type of rhizome, a horizontal underground stem, which exhibits a long, slender structure and rapid growth with a dense, branched appearance.</p> Signup and view all the answers

What is the function of adventitious roots in a plant?

<p>Adventitious roots are specialized roots that arise from a plant's stem or leaves. Their primary function is to provide additional anchoring and support for the plant, particularly in environments that lack a firm rooting medium or if the main root system is damaged.</p> Signup and view all the answers

Which of the following types of subterranean stems is commonly found in potatoes?

<p>Stem tuber (D)</p> Signup and view all the answers

What are the key structural features of a corm?

<p>A corm is a shortened, swollen underground stem that often has brown, scale-like leaves attached, notably found at the base of the stem. It has an apical bud for producing new growth and axillary buds for lateral development.</p> Signup and view all the answers

A rootstock is essentially a vertically grown rhizome with shortened internodes.

<p>True (A)</p> Signup and view all the answers

Explain the function of a rootstock in plant cultivation.

<p>Rootstocks, which are thickened, vertically growing rhizomes, play a vital role in plant cultivation. They serve as a foundation for grafting, where cuttings or scions of a desirable variety are joined to the rootstock. This practice combines the root system from the rootstock with the desired growth features of the scion, resulting in a hybrid plant with enhanced characteristics or disease resistance.</p> Signup and view all the answers

The structure of older roots is almost identical to that of younger roots.

<p>False (B)</p> Signup and view all the answers

Stolons are underground stems that are primarily associated with waterlogged soil conditions.

<p>False (B)</p> Signup and view all the answers

What are the defining characteristics of a rootstock?

<p>Rootstocks are thickened, vertical rhizomes with shortened internodes, they are a common element for grafting in the manipulation of desirable traits in plants.</p> Signup and view all the answers

What type of plant is a good example of a plant with a rootstock?

<p>Gentian</p> Signup and view all the answers

The presence of axillary buds is a key distinction that allows for the differentiation of a subterranean stem from a root.

<p>True (A)</p> Signup and view all the answers

What are the main functions of a bulb in a plant?

<p>Bulbs serve as specialized underground stems used for storing food reserves, they also act as a means of plant propagation, enabling new plants to develop from the bulb.</p> Signup and view all the answers

All underground stems are specialized for propagation and food storage.

<p>True (A)</p> Signup and view all the answers

Which of the following statements best describes the term ‘Tunicated bulb’?

<p>A type of bulb composed of layers of thick fleshy scales that are more or less separate. (C)</p> Signup and view all the answers

Tunicated bulbs are easier to divide than scaly bulbs.

<p>False (B)</p> Signup and view all the answers

What are the key structural features that distinguish a corm from a bulb?

<p>A corm is a solid, upright, compact underground stem with small, scale leaves, while a bulb is primarily composed of fleshy scales that are more or less separate, forming a tunic or covering around the bud for propagation.</p> Signup and view all the answers

What is the main difference between a rhizome and a stolon?

<p>A rhizome is a horizontal, underground stem that typically grows deeper underground, often with lateral branches, and is commonly used for propagation. A stolon, conversely, is a horizontal underground stem that usually grows near the surface, and is often seen as an extension of a stem, also used for propagation.</p> Signup and view all the answers

What are the primary differences between a stem tuber and a root tuber?

<p>A stem tuber develops from a swollen underground stem, while a root tuber develops from a swollen root. Stem tubers are primarily used for food storage and propagation, and they can have small scales and buds, while root tubers are not used for propagation and typically lack these structures.</p> Signup and view all the answers

Which of the following is NOT a characteristic of a corm?

<p>It is always formed from the root system. (C)</p> Signup and view all the answers

What is the main function of a stolon?

<p>Stolons, as horizontal underground stems, are primarily used for propagation and spreading a plant. This is often achieved through the formation of new plants at points along the stolon.</p> Signup and view all the answers

All underground stems are typically devoid of chlorophyll.

<p>True (A)</p> Signup and view all the answers

Young roots are typically characterized by a more complex vascular system than old roots.

<p>False (B)</p> Signup and view all the answers

Rootstocks are typically used to create hybrid plants with desirable characteristics, such as disease resistance.

<p>True (A)</p> Signup and view all the answers

What are the two main functions of subterranean stems in plants?

<p>Subterranean stems serve two key functions: vegetative propagation and food storage. They help plants spread and reproduce asexually, and they provide essential nutrients and resources for future growth.</p> Signup and view all the answers

The type of plant's root system can significantly influence its ability to withstand drought conditions.

<p>True (A)</p> Signup and view all the answers

What is the difference between root stocks and root tubers?

<p>Both B and C (A)</p> Signup and view all the answers

Flashcards

Root

The portion of the plant axis that grows vertically downward into the soil, lacking leaves, buds, and chlorophyll, with a root-cap covering its growing point.

Rhizome

A thick, horizontal underground stem that stores food and serves for propagation. It has nodes, scale leaves, and adventitious roots.

Stem tuber

A swollen underground stem, primarily its tip, full of food materials and serving for vegetative propagation. They have buds and small scales.

Rootstock

A vertical rhizome with short internodes and ring-shaped leaf scars, often with transverse wrinkles due to growth.

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Corm

A swollen, erect underground stem formed from the base of the plant. It's covered by scale leaves and has an apical bud.

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Bulb

A reduced underground stem with fleshy scaly leaf bases that store food. They are typically crowned with a bud.

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Sobole

A type of rhizome that is long, thin, grows rapidly, and has extended internodes. It acts as a creeping stem.

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Sucker

A branch growing from the stem or root below the ground, commonly associated with propagation.

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Prop root

Adventitious roots arising from the stem, growing down to anchor the plant in the soil. Often seen in plants growing in shallow soil.

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Aerial root

Roots that grow from the stem above ground, often for absorbing water.

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Fibrous root

Roots that are very slender and numerous, forming a fibrous network.

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Storage root

Roots that are swollen with stored food material, such as in carrots.

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Young root

A young root with distinct zones of growth, including the root cap, meristem, elongation zone, and maturation zone.

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Old root

A root that has undergone secondary growth, developing a vascular cambium and cork cambium.

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Primary root

A type of root that develops directly from the seed during germination, forming the main root.

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Secondary root

Roots that grow laterally from the primary root, branching from the main root.

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Adventitious root

Roots that develop in locations other than the main root or its branches, typically arising from the stem.

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Tap root

A root that develops a tap root, a single dominant root extending vertically downward.

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Tegumentry layer

The outer protective layer of a subterranean stem, composed of either epidermis or cork.

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Cortex

The layer of cells that lies beneath the epidermis or cork of a subterranean stem.

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Endodermis

A layer of cells that separates the cortex from the vascular bundles in a subterranean stem.

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Vascular bundles

The vascular bundles arranged in a circle in the subterranean stem.

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Pith

The central core of a subterranean stem, usually filled with parenchymatous cells.

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Open vascular bundle

A type of vascular bundle that remains open, allowing for secondary growth of the stem.

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Closed vascular bundle

A type of vascular bundle that remains closed, preventing secondary growth of the stem.

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Dictyostele

A type of vascular arrangement, forming a network of interconnected vascular bundles in the stem.

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Radial vascular bundle

The presence of a central solid mass of xylem in the root.

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Collateral vascular bundle

A type of vascular bundle that is not arranged in a radial pattern, found in stems.

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Secondary growth

The process of growth in which a plant increases in thickness due to the activity of the vascular cambium and cork cambium.

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Primary growth

A type of growth in which a plant increases in length due to the activity of apical meristems.

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Vascular cambium

A layer of cells that forms between the xylem and phloem in stems and roots, responsible for secondary growth. The vascular cambium cell division is the primary reason for secondary growth.

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Cork cambium

A layer of cells that is responsible for producing the cork, a protective outer layer in stems.

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Cork

The outer layer of a plant stem, primarily composed of cork cells.

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Phelloderm

The layer of cells that is found beneath the cork in plant stems, formed by the cork cambium.

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Study Notes

Course Information

  • Course Title: Pharmacognosy II
  • Course Code: PHG 213
  • Week Number: 9
  • Lecture Number: 7
  • Lecturer: Dr. Hanan Samir Marzouk
  • Academic Year: Fall 2024/2025

Classroom Etiquette

  • No Talking

Subterranean Organs (Under Ground Organs)

  • Subterranean organs are primarily storage organs.
  • They store reserve food materials.

Main Characters of Subterranean Organs

  • Subterranean organs lack chlorophyll.
  • Food storage occurs as starch in Filixmas and Rhubarb
  • Sugars are stored in Gentian
  • Inulin is stored in plants from the Asteraceae family (Compositae)

Roots

  • Roots grow downwards, never developing leaves.
  • Roots have a root cap (calyptra) that protects the growing point
  • Roots lack nodes and internodes.
  • Lateral roots originate endogenously.
  • Lateral roots arise from the pericycle or endodermis of the stem.
  • Lateral roots appear in rows, either equal to or double the number of primary xylem groups.

Types of Roots

  • Primary root (e.g., Senega)
  • Secondary root (e.g., Krameria)
  • Adventitious root (e.g., Ipecacuanha)
  • Prop root (e.g., Maize)
  • Fibrous root (e.g., Grass)
  • Aerial root (e.g., Ficus, Hedera)
  • Respiratory root (e.g., some plants in waterlogged soil)
  • Storage root (root tubers; e.g., Belladonna, Umbelliferous, Calumba)
  • Taproot
  • Additional root types (e.g., Fibrous, storage, aerial) are elaborated.

Types of Roots: (More detailed description)

  • Primary roots, develop into taproots in some species.
  • Secondary roots are lateral roots emerging from the primary root.
  • Adventitious roots grow from the stem or branches.
  • Prop roots grow from the stem, partially above ground.
  • Fibrous roots are slender, common in grasses.
  • Aerial roots are specialized for various purposes.
  • Storage roots are swollen for food storage.

General Scheme for Description of Roots

  • Condition: Dry or Fresh, Entire or sliced, Peeled
  • Shape and Size: Cylindrical, Subcylindrical, Teret, Twisted, Obconical, Fusiform, Napiform
  • Type: Classification of root types (e.g., tap, fibrous, etc.)

Structure of Roots (Histology or Microscopical Characters)

  • Young roots: Monocot and Dicot roots are contrasted.
  • Monocot: A characteristic ring of vascular tissues in the center.
  • Dicot: Vascular tissues form a star-shaped pattern.
  • Old roots (Secondary Structure): Older roots exhibit the development of secondary tissues.

The following T.S. categorization question:

  • Determine if the provided transverse section (T.S.) is from a young monocot, old monocot, young dicot, or old dicot root.

Activity I (Identify Root Types)

  • Identify root types based on descriptions and diagrams provided.

Subterranean Stems

  • Functionally, subterranean stems are important for propagation and storage.
  • Distinguished from roots by scale leaves, axillary buds, and adventitious roots.
  • They lack a central solid xylem mass, typically having a parenchymatous pith instead.

Subterranean Stem Features and Distinctions from Aerial Stems

  • Scale leaves instead of foliage leaves.
  • Adventitious roots arising typically from nodes.

Direction of Growth: (Subterranean Stems)

  • Horizontally
  • Vertically
  • Obliquely.

Types of Subterranean Stems (Detailed listing)

  • Rhizome (e.g., Rhubarb)
  • Root Stock (e.g., Senega)
  • Sobole (e.g., Couch Grass)
  • Sucker (e.g., Mentha, Rose)
  • Stem Tuber (e.g., Potato)
  • Corm (e.g., Colcasia, Colchicum)
  • Bulb (scaly bulb or tunicated bulb)

Additional Features and Activities of Subterranean Stems:

  • Rhizomes exhibit nodes and internodes.
  • Suckers come from the stem or roots.
  • Stem tubers (e.g., Potato) are swollen underground stems, differentiated from root tubers.
  • Corms (e.g., Colocasia, Colchicum) are thickened stem bases enclosed by fleshy leaves or scales.
  • Bulbs are stored food structures with leaves or fleshy scales.

General Scheme for Describing Subterranean Stems

  • Condition: Dry/Fresh, entire/sliced, pealed, broken pieces.
  • Shape and Size
  • Direction of Growth
  • Mode of branching
  • Kind: Categorization of subterranean stem types.

Structure of Subterranean Stems

  • The Tegumentary Layer: Epidermis, Cork.
  • Cortex
  • Endodermis
  • Vascular Bundles: Open/closed dictyostele.

Differentiating Subterranean Stems from Roots

  • Presence/Absence of pith
  • Presence/absence of radial vascular bundles

Activity II (Identify Stem Types)

  • Identify types of subterranean stems (e.g., corm, rhizome, etc.) from cross-sections (transverse sections).

Differences Between Roots and Subterranean Stems (Table Format)

  • Morphological differences
  • Histological differences

Homework Assignments

  • Differentiate between subterranean organs and other plant organs.
  • Differentiate between subterranean roots and stems.
  • Differentiate between young and old roots.
  • Differentiate between young monocot and dicot roots.
  • Differentiate between young and old stems.

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Pharmacognosy II Lecture Notes Fall 2024/2025 PDF

Description

Test your knowledge on subterranean organs in Pharmacognosy II. This quiz covers the characteristics, functions, and types of roots as well as their role in food storage. Ensure you are familiar with key terms and concepts discussed in Week 9.

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