Podcast
Questions and Answers
What is the hilum in a seed?
What is the hilum in a seed?
- The outer layer of the seed
- The scar left by removal of seed from its funicle (correct)
- The structure that transports nutrients
- The area where the seed undergoes photosynthesis
What role does the micropyle serve in a seed?
What role does the micropyle serve in a seed?
- It allows for nutrient absorption
- It protects the seed from pests
- It aids in water transport during germination (correct)
- It stores energy for the seed
Why is the micropyle an important feature of the seed coat?
Why is the micropyle an important feature of the seed coat?
- It prevents water loss
- It serves as a passage for water during germination (correct)
- It enhances seed color for attraction
- It allows air exchange
What results from the removal of a seed from its funicle?
What results from the removal of a seed from its funicle?
Which statement best describes the seed coat's apex?
Which statement best describes the seed coat's apex?
What is the primary transformation that occurs to ovules?
What is the primary transformation that occurs to ovules?
What happens to the ovary after the ovules transform?
What happens to the ovary after the ovules transform?
Which of the following best describes the relationship between seeds and fruit?
Which of the following best describes the relationship between seeds and fruit?
Which of the following statements about seeds is true?
Which of the following statements about seeds is true?
What is the role of the ovary in seed formation?
What is the role of the ovary in seed formation?
What is the main function of the endosperm in a typical seed?
What is the main function of the endosperm in a typical seed?
Which part of the seed is developed from the fertilized egg ovum?
Which part of the seed is developed from the fertilized egg ovum?
Which structure originates from the nucellus?
Which structure originates from the nucellus?
What does the testa in a seed refer to?
What does the testa in a seed refer to?
Which of the following statements about the kernel is correct?
Which of the following statements about the kernel is correct?
What are cotyledons commonly known as in the context of plant development?
What are cotyledons commonly known as in the context of plant development?
Which best describes fertilization in plants?
Which best describes fertilization in plants?
What is the primary function of the cotyledons during early seed development?
What is the primary function of the cotyledons during early seed development?
In the context of fertilization, what is the outcome of the fusion process?
In the context of fertilization, what is the outcome of the fusion process?
Which of the following statements about embryos and cotyledons is true?
Which of the following statements about embryos and cotyledons is true?
What is the primary difference between exalbuminous and albuminous seeds?
What is the primary difference between exalbuminous and albuminous seeds?
Which seed type is associated with the presence of a well-developed perisperm?
Which seed type is associated with the presence of a well-developed perisperm?
What structure in the seed is responsible for the seed's external appearance including the position of the radicle?
What structure in the seed is responsible for the seed's external appearance including the position of the radicle?
In which type of seeds does the endosperm develop?
In which type of seeds does the endosperm develop?
What is the role of the micropyle in seed anatomy?
What is the role of the micropyle in seed anatomy?
What is the primary distinction between exalbuminous seeds and albuminous seeds?
What is the primary distinction between exalbuminous seeds and albuminous seeds?
In the development of exalbuminous seeds, which part is typically absorbed during the process?
In the development of exalbuminous seeds, which part is typically absorbed during the process?
What is the characteristic feature of the zygote in exalbuminous seeds?
What is the characteristic feature of the zygote in exalbuminous seeds?
Which of the following seeds is an example of exalbuminous seeds?
Which of the following seeds is an example of exalbuminous seeds?
In the context of seed development, what role does the testa play in exalbuminous seeds?
In the context of seed development, what role does the testa play in exalbuminous seeds?
Flashcards
Ovule
Ovule
The female reproductive structure in a flower that contains the ovule.
Seed
Seed
The mature ovule after fertilization, containing the embryo and food reserves.
Ovule to Seed Transformation
Ovule to Seed Transformation
The process of an ovule transforming into a seed.
Fruit
Fruit
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Seed Function
Seed Function
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Cotyledons
Cotyledons
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Fertilization
Fertilization
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Embryo
Embryo
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Embryo development
Embryo development
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Fertilization of the egg
Fertilization of the egg
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Hilum
Hilum
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Micropyle
Micropyle
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Funicle
Funicle
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Seed Coat
Seed Coat
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Germination
Germination
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Testa
Testa
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Kernel
Kernel
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Endosperm
Endosperm
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Perisperm
Perisperm
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Exalbuminous Seeds
Exalbuminous Seeds
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Nucellus
Nucellus
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Embryo Sac
Embryo Sac
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Albuminous Seeds
Albuminous Seeds
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Study Notes
Course Information
- Course Name: Pharmacognosy II
- Course Code: PG303
- University: Egyptian Chinese University
- Faculty: Faculty of Pharmacy and Drug Technology
Course Grades
- Periodical exam: 20 marks
- Practical exam: 40 marks
- Oral exam: 15 marks
- Final exam: 75 marks
Week 1: Introduction to Seeds
- Topics Covered: Seed structure, diagram showing parts of pea flower and pea pod; different examples of seeds like dandelions, chestnuts, etc.
- Seed Definition: A seed is a plant part derived from a fertilized ovule. It is a mature fertilized ovule containing an embryo.
- Ovule Transformation: Ovules transform into seeds.
- Ovary Enlargement: The ovary swells and enlarges to form the fruit that encloses the seeds.
- Parts of a Flower: Images displaying the stigma, ovary wall, ovule (with a focus on pea flower and pea pod)
Introduction to Seeds
- Key facts about Seeds: A mature fertilized ovule with an embryo inside.
Structure of the Ovule
- Key Parts of a Mature Ovule:
- Integuments: protective outer covering
- Testa: Protection of the seed
- Micropyle: Opening for pollen tube entrance.
- Nucellus: nutritive tissue, often contains perisperm
- Endosperm: nutritive tissue.
- Embryo sac/Megaspore: Contains the embryo.
- Embryo: the developing organism.
- Funicle: small stalk that attaches the ovule to the placenta.
- Chalaza: The basal part of the nucellus where the integuments attach
Structure of the Ovule (Continued)
- Parts and their Roles: Each part has a specific function.
Pollination and Fertilization
- Pollination Details: Pollen landing on the stigma of the flower starts the process. The pollen tube grows down in the style to the ovule.
- Double Fertilization: One sperm fertilizes the egg cell, and the other sperm fuses with polar nuclei to form endosperm.
- Seed Formation: The seed develops from the fertilized ovule, after pollination and fertilization. The embryo sac (inside the ovule) develops into embryo.
Function of Seeds
- Key Functions of Seeds:
- Ensure continuation and distribution of the species.
- Facilitate transportation to new locations.
Fertilization and Development of Embryo
- Fertilization Definition: The fusion of male and female nuclei.
- Pollen Tube Entry: The pollen tube enters the ovule through the micropyle. Inside it enters the embryo sac.
- Embryo Development: The embryo's formation causes changes in the ovule and ovary.
- Seed Development: The ovule's swelling and development into a seed.
- Testa Function: The testa protects the embryo from injury and drying during this process.
The Mature Ovule
- Â Nucellus: Parenchymatous tissue
- Â Chalaza: Basal part of the nucellus.
- Â Funicle: Stalk attaching ovule to placenta.
- Embryo Sac: Contains cells crucial for future development.
Raphe
- Raphe formation: Fusion of the funicle with the integument.
Types of Ovules
- Anatropous: Ovule flipped 180 degrees with the micropyle adjacent to the hilum and the chalaza at the distal end.
- Â Orthotropous: Straight ovule, funicle runs in a straight line with micropyle, chalaza, and hilum in same straight line (no raphe).
- Amphitropous: Ovule is bent so that micropyle and chalaza are on a line perpendicular to the funicle.
- Â Campylotropous: Bent ovule with micropyle and chalaza close to each other.
External Appearance of a Seed
- Markings: Hilum (scar) where seed was attached to funicle, Micropyle (opening), position of the radicle.
- Testa: Seed coat.
Types of Seeds
- Exalbuminous: Non-endospermic (e.g. beans)
- Albuminous: Endospermic (e.g. grasses)
- Perisperm: Perisperm is a nutritive tissue that arise from cells of the nucellus.
Types of Embryo
- Orthotropous, Accumbent, Incumbent, Coiled
Types of Outgrowths
- Arilus (from funicle/hilum), Arillode (from micropyle), Caruncle (from the tissue surrounding micropyle), Strophiole (local enlargement over position of raphe) , Wing (membranous), Tuft of hairs (sessile/stalked)
The Testa (Texture and Shape)
- Â Membranous (Almond)
- Â Leathery (Linseed)
- Â Hard (Nutmeg)
- Â Woody (Calabar bean)
- Â Fleshy (Mangolia)
- Â Longitudinally striated (Almond)
- Smooth (Linseed)
- Papillosed (Grain of paradise)
- Pitted (Digitalis)
- Reticulated (Poppy)
- Hairy (Nux vomica)
- Rugged (Cardamom)
Microscopical Characters
- Testa: Layers (e.g., epidermis, sclerenchyma, nutritive)
- Perisperm: Parenchyma cells with starch.
- Endosperm: Parenchyma cells with starch, protein, and fixed oils.
- Embryo
- Cell Contents: Starch, protein, fixed oils
Reserved Food Materials
- Carbohydrates: Starch, cellulose, and hemicellulose
- Fixed oils and proteins (aleurone grains)
Types of Aleurone Grains
- Simple: Amorphous protein mass surrounded by membrane (leguminous seeds).
- Complex: Crystalline (e.g., crystalloid), Globose (e.g.,globoid) embedded in protein.
Ground and Globoids Substance
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